The Audio Critic: Web ’Zine - Page 2
26 April, 2007
Electronic Signal Paths Do Not Have a Personality!
I keep forgetting that my newer readers outnumber the old-timers and that some of the basic truths about audio that are old hat to me and to the regulars are new and fresh to the recent arrivals. Here is something, therefore, worth repeating for the nth time.
Every low-distortion electronic signal path sounds like every other. The equipment reviewers who hear differences in soundstaging, front-to-back depth, image height, separation of instruments, etc., etc., between this and that preamplifier, CD player, or power amplifier are totally delusional. Such differences belong strictly to the domain of loudspeakers. Depending on the wave-launch characteristics, polar pattern, or power response of the loudspeaker (those are overlapping concepts), the stereo presentation of the program material can vary greatly. It cannot vary as a result of the properties of a normal (i.e., low-distortion) electronic signal path. The only exception I can think of would be totally inadequate channel separation (less than, say, 30 dB) between the left and right channels of a stereo device, which is hardly ever the case—and certainly not when high-end components are being discussed by said reviewers.
Beware, therefore, of electronic audio components with a personality. If they have a personality, they are either defective or the brainchild of a reviewer without accountability.
27 February, 2007
A New, and in Some Ways Preferable, A/B Comparison Technique
I have believed for decades now that the only scientifically valid technique of A/B-ing two audio components against each other was a double-blind ABX listening comparison at matched levels. Now Bill Waslo of Liberty Instruments has come up with a new methodology that has the potential of being more widely used because it is simpler, takes less time and less fussing, and is basically automated.
The essence of the process is this: Record the output of an audio component when playing any piece of music, or even a test signal. Then change something in the system—a cable, an amplifier, any other component, or apply an audiophile tweak of any kind. Next, record the output again with the same piece of music or the same test signal. Then, using Bill Waslo’s “Audio DiffMaker” software (which has not been commercially released yet but can be downloaded in a trial version), align the two recorded tracks to the same gain level and timing. Finally, subtract one from the other and listen to the difference recording. If it is basically silent, then the change has clearly done nothing. No sound in the difference recording means that the change has made no difference. If the track is not silent, then a difference may have been made by the change, and further investigation is warranted.
A simple schematic of the process is the following, courtesy of Liberty Instruments: Now, I am not saying (and neither does Bill Waslo) that Audio DiffMaker will convince the flat-earthers who remain unconvinced by ABX listening comparisons. There is such a thing as invincible ignorance. What I am saying is that AudioDiffmaker is scientifically sound, more convenient than ABX (automatic level matching, no endless iterations, etc.), and considerably more sensitive than the human ear. The difference recording may in some cases have a tiny signal on it below the threshold of audibility. The important thing from the audio point of view is—can you hear the difference? Listening directly to the difference, and only the difference, instead of iterated A/B comparisons is the main advantage of Audio DiffMaker. It will be interesting to see whether this new technique takes off, at least in electroacoustically sophisticated circles. Much more detailed information is available by going to http://libinst.com/Audio%20DiffMaker.htm.
01 January, 2007
As always, I am reviewing only those CDs, new or fairly recent, that I found interesting. (Sometimes even a bad performance can be interesting.) Just because they sent me a review copy is insufficient reason for a review in this Web ’zine; there are plenty of other reviewers out there who will oblige.
SACD from Channel Classics
Gustav Mahler: Symphony No. 2 in C Minor (“Resurrection”). Birgit Remmert, mezzosoprano/alto; Lisa Milne, soprano; Hungarian Radio Choir; Budapest Festival Orchestra, Iván Fischer, conductor. CCS SA 23506 (2 SACDs, recorded 2005, released 2006).
“A symphony should be like the world: it must embrace everything,” Mahler is supposed to have said, and the Second is the earliest gigantic work reflecting that creed, still completely free from the mannerisms and self-indulgence of some of the later symphonies. You don’t have to be a Mahlerian to love the Second (or the Third). This recording by Iván Fischer is a sequel to that of the Sixth reviewed here about a year ago, made with the same orchestra and technical crew in the state-of-the-art Béla Bartók National Concert Hall in the Palace of Arts in Budapest. I will not repeat my encomiums regarding the hall, suspect as they were of Hungarian chauvinism, but I must reluctantly admit that the Mahler recording in Philadelphia’s comparable Verizon Hall (see below) sounds even a little better, especially the 5.0 layer, although this one too is very high-class audio. Fischer’s performance once again emphasizes the big line, the totality of the work; he conducts the forest, not the trees (again, see below). The soloists and the choir are excellent. Of course, the competition in Mahler Seconds is huge. Speaking of Philadelphia, Fischer guest-conducted the Philadelphia Orchestra recently and made a tremendous impression. The musicians loved him. Does this mean he is a dark horse to follow Eschenbach when the latter retires after the 2007-08 season? No one says so, but you heard it here first…
CD from EMICarl Orff: Carmina Burana. Sally Matthews, soprano; Lawrence Brownlee, tenor; Christian Gerhaher, baritone; Rundfunkchor Berlin; Berliner Philharmoniker, Sir Simon Rattle, conductor. 7243 5 57888 2 5 (recorded 2004, released 2005).
A poor performance of Carmina Burana is almost impossible; everybody employing the required forces does a more or less decent job because the piece is totally simplistic—no harmony, no counterpoint, simple rhythms, unison singing, unsubtle aggressive percussion. That the piece is so effective is utterly amazing (must be the catchy tunes). The best performances are characterized by high energy to the point of wild abandon, combined with precise execution plus superior singing. This is definitely one of those best performances, and since the live stereo recording is also excellent, one of the better efforts in the tricky Philharmonie, the whole production must be rated as top rung. The awesome competence of Rattle and the Berlin Philharmonic is almost overkill for the piece. Baritone Christian Gerhaher is a standout, better than most singers in the role. If you don’t have a recording of this oddball quasi-masterpiece, you might as well get this one.
SACD from the Fry Street QuartetJoseph Haydn: String Quartet in D Minor, Op. 9, No. 4; String Quartet in F Major, Op. 77, No. 2. The Fry Street Quartet (Jessica Guideri, violin; Rebecca McFaul, violin; Russell Fallstad, viola; Anne Francis, cello). FSQCD4 (recorded 2005, released 2006).
This is another IsoMike recording by Ray Kimber under the Fry Street Quartet label. The first one I reviewed here some time ago and declared it to be the new “state of the art” in chamber-music recording, surpassing all previous efforts in realistic, lifelike string sound. This one is even a little better, if such a thing is possible. The warmth, the presence, the sheer you-are-thereness of the violins, viola, and cello are unprecedented. (Yes, Ray, your cable marketing sins are forgiven.) Op. 77, No. 2, dating from 1799, is one of the greatest, if not the greatest, string quartet of Haydn, an absolutely stunning work surpassed only by the best of Beethoven (whose earliest quartets are roughly contemporaneous). Op. 9, No. 4, composed some thirty years earlier, is good music but not quite in the same league. The Fry Street Quartet, as I wrote before, is as good as some of the big names that are much better known. They play with superb musicality and unfailing beauty of tone. For a wonderful musical experience and a unique audio treat, get this CD. (I like the stereo layer at least as much as the 4-channel surround layer.)
CD from Harmonia Mundi
Anton Bruckner: Symphony No. 4 in E-flat Major (“Romantic,” 1878/80 revision, ed. Nowak). Orchestre des Champs-Élysées, Philippe Herreweghe, conductor. HMC 901921 (recorded 2005, released 2006).
This one is controversial. Like Herreweghe’s recording of the Seventh reviewed here several installments ago, it is “Bruckner Lite,” and you have the right to love it or hate it. I happen to think that the added transparency achieved with 19th-century instruments and the nonpompous treatment of the musical material yield a highly viable alternative to the monumental Bruckner style. Bruckner may have been a Wagnerian but he was no Wagner; the Götterdämmerung approach to some his passages runs the risk of self-parody if the conductor isn’t careful. Emphasizing the classical side of the music isn’t such a bad idea. I still want to hear the Karajan kind of Bruckner from time to time, but Herreweghe’s approach is refreshing. The stereo recording in a smallish auditorium in Dijon is very realistic of its kind.
CDs from Naxos
Béla Bartók: Mikrokosmos (Complete): Books 1–6. Jenö Jandó, piano. 8.557821-22 (2 CDs, recorded 2005, released 2006).
Not for the fainthearted—153 increasingly complex piano pieces, ranging from the naïvest simplicity to diabolic virtuoso exercises, the shortest lasting 16 seconds, the longest over 4½ minutes. No other composer has tried anything remotely like it; most of it is of pedagogical importance rather than concert-hall material, but Books 5 and 6 contain some brilliant performance pieces. Bartók’s utter devotion to the essence of music, without the slightest attention to the possibility of worldly success, could not be better exemplified than by this monumental work. Jandó is a well-established Bartókian, and I hear nothing to fault in his performance, right up to the virtuoso rendering of the terminal complexities. The recording of the piano is close-up and extremely real, typical of the work of the excellent Phoenix Studio in Budapest.
Aaron Copland: Prairie Journal (1937); Rodeo: Four Dance Episodes (1942); Letter from Home (1944); The Red Pony—Film Music: Suite (1948). Buffalo Philharmonic Orchestra, JoAnn Falletta, conductor. 8.559240 (recorded 2005, released 2006).
Big surprise. The Buffalo Philharmonic is a very high-quality orchestra; JoAnn Falletta is an excellent conductor; Kleinhans Music Hall in Buffalo is a world-class venue. Others may know these things; I didn’t. To perform Copland’s rural/cowboy/American/pop pieces with maximum impact, you have to swing it, not just a little (like, for instance, Michael Tilson Thomas) but a lot. Falletta and the Buffalo musicians dig into it with real gusto, maximizing the rhythms, and it makes a difference. They sound great. As for the audio, my jaw dropped when I listened to the reproduction of the Kleinhans acoustics. How come they don’t make more recordings here? What a great hall! The bass is especially fabulous. This is definitely a CD which is more than meets the eye.
Franz Schubert: Piano Trio No. 2 in E-flat Major, D. 929, Op. 100; Sonatensatz in B-flat Major, D. 28. Kungsbacka Piano Trio (Malin Broman, violin; Jesper Svedberg, cello; Simon Crawford-Phillips, piano). 8.555700 (recorded 2003, released 2006).
If you have seen Barry Lyndon, Stanley Kubrick’s great 1975 movie, you probably remember from the soundtrack the haunting andante con moto of the E-flat trio, even if you are unfamiliar with the whole work. It is late Schubert, and that means sublime music, regardless of Deutsch number or opus number. In the last few years of his short life Schubert was in a zone of transcendence. D. 28 is a work of adolescence and not comparable. The Kungsbacka trio, a youngish ensemble that started in Sweden and is based in England, provides an alert and highly transparent performance, maybe a little too foursquare for my taste—I can imagine a more poetic interpretation—but their intonation is flawless. They play every repeat of the sprawling work, stretching it to nearly an hour (not that I’d want it to stop). The violin tone of Malin Broman is occasionally a little wiry, emphasized by the superbly lifelike English recording.
SACD from Ondine
Gustav Mahler: Symphony No. 6 in A Minor; Piano Quartet movement in A Minor (1876). The Philadelphia Orchestra, Christoph Eschenbach, conductor; in the quartet, members of The Philadelphia Orchestra (Christoph Eschenbach, piano; David Kim, violin; Choong-Jin Chang, viola; Efe Baltacigil, cello). ODE 1084-5D (2 CD/SACDs, 2005-2006).
Some conductors conduct the forest, others the trees. Toscanini is a good example of the former, Eschenbach of the latter. That’s an oversimplification, of course, because both kinds of conductors, if they are worth their salt, conduct with full awareness of the overall sweep and structure of the piece as well as its details. It’s a question of emphasis. Eschenbach doesn’t reveal anything we didn’t already know about the Mahler Sixth as a totality but he brings out every little detail with amazing lucidity and differentiation. Call it “overconducting”—I love it! I happen to disagree with those who consider this to be Mahler’s greatest symphony but I can’t think of another version I would rather listen to. When Eschenbach leaves Philadelphia at the end of the 2007-08 season, I wonder what great improvements will follow. The sound, too, is superb, the best of the Philadelphia/Ondine series so far. The tunable Verizon Hall has finally been optimized to the nth degree. There are still too many microphones but they are needed for safety; you can’t gamble with “purist” techniques when recording live before an audience. I am completely happy with both the stereo and the multichannel versions; the 5.0 layer is particularly successful in rendering a 3-D space rather than just directional cues.
CD from Profil
Franz Schubert: Symphony No. 9 in C Major, D. 944. Münchner Philharmonker, Günter Wand, conductor. PH06014 (recorded 1993, digitally remastered and released 2006).
Günter Wand has been dead almost five years, but various record labels keep issuing late-in-life recordings by him. This one he made when he was 81 (he died at 90), and for sheer musicality and echt Schubert style it’s a hard-to-beat performance. Wand was a musician’s musician to the end of his life. The tempi are leisurely (Toscanini’s famous Philadelphia Orchestra recording of 1941, for example, is nine minutes faster), but that’s a German super-Kapellmeister’s way with Schubert—noble might be the best word for it—and it works. There are too many recordings of this stupendous symphony to rank this one (Wand alone made several) but it clearly belongs in the upper percentiles. The Munich Philharmonic was not one of Wand’s regular (contractual) orchestras, but he guest-conducted it frequently throughout his life and had an excellent rapport with it, although his Munich recordings could not be legally released before his death. It is an excellent orchestra, just short of world-class, and the stereo recording is also very good, without any eccentricities or exaggerations. The whole effort is an exercise in superior taste.
SACD from RCA Red Seal
Johann Strauss Jr. et al.: “Vienna” (waltzes by Johann Strauss Jr., Josef Strauss, Carl Maria von Weber, and Richard Strauss). Chicago Symphony Orchestra, Fritz Reiner, conductor. 82876-71615-2 (recorded 1957 and 1960, remastered and released 2006).
You think you know how a Viennese waltz should sound? Don’t be too sure. Listen to the very first track on this disc, Morning Papers, Op. 279, of Johann Strauss Jr. Who else beside Reiner conducts a Strauss waltz with this kind of Viennese lilt, with exactly the right hesitation on the second beat and with that infectious exhilaration in the fast passages? Not many, not even most of the conductors of the Wiener Philharmoniker’s annual New Year’s concert (certainly not Zubin Mehta on Jan. 1, 2007). Of course, it helps to have been born in 1888 in Austria-Hungary under Franz Josef. Strauss died in 1899, so little Fritz grew up hearing the real thing. All in all, this is perhaps my all-time favorite Strauss waltz recording, comprising seven pieces by the immortal “Schani” (yes, all the big ones are here), and it even offers extra goodies like the Weber-Berlioz Invitation to the Dance and the Rosenkavalier waltzes. The orchestral playing is awesome, needless to say; the midcentury Chicago orchestra has never been surpassed. As for the audio (this is, after all, an audio journal), it is equally amazing. Lewis Layton, maybe the greatest recording engineer of all time, knew more about microphone placement, hall acoustics, and tape editing fifty years ago than most of today’s top guns with their state-of-the-art equipment. As a result, the soundstage, the instrumental timbres, and the hall effects are as good as today’s best (with maybe just a tad more distortion) and a lot better than today’s average. Orchestra Hall in Chicago, before they renovated it, was probably the most “phonogenic” venue in the United States. The SACD multichannel remastering preserves the original three-channel (left/center/right) recording; the rear channels are silent. I don’t think the center channel makes a huge difference, but the hi-rez DSD technology effects a clear improvement over previous editions. Bottom line: can’t ask for better Strauss or better sound.
25 December, 2006
A Note About Loudspeakers
I have written about this many times before but I keep forgetting that more of my readers are first-timers than longtime habitués. So, even if you know little or nothing else about audio, be aware of this:
The loudspeaker will determine how your music system sounds. Not the amplifier, not the preamplifier, not the CD or DVD player, nothing but the loudspeaker. Speakers, even the finest, are far less accurate in terms of output compared to input than any of those other components. The speaker will be invariably the weakest link in the chain, the link that limits the quality of sound reproduction.
I am always cynically amused when an audiophile brings home a shiny new amplifier in his hot little hands, breathlessly connects it to the dinky little box speakers anything larger than which his spouse won’t allow, and turns on the music. The sound is exactly the same as it was before with his older, cheaper, less fancy amplifier, but of course he will not admit it. If he had spent his money on better loudspeakers instead, the improvement in sound would have been inarguable.
But what is a “better” loudspeaker? The standard model, employing forward-firing dynamic drivers with a passive crossover in a closed box, has been refined to the point where further improvements are most unlikely. There are small ones and big ones, simple ones and elaborate ones, $600 ones and $45,000 ones, but if they are correctly designed (admittedly not always the case), the sound will always be of the same general quality—wide-range, smooth, effortless, but not quite real, with a slightly closed-down, boxy characteristic that says: loudspeaker, not live. There’s a ceiling in performance with this type of loudspeaker, maybe at three or four thousand dollars, above which you get very little, if anything, regardless of the hyperbolic claims and insane prices of some ultrahigh-end models. I have revived the old-time “monkey coffin” label, used by 1970s hi-fi salesmen, for this category of box speakers. There are dinky little monkey coffins and huge expensive monkey coffins, but they all sound like monkey coffins, more or less. If you seek sound that more closely resembles live music, you have to look into loudspeaker designs that depart from the standard model. Two of these have been reviewed in this Web ’zine, the Bang & Olufsen BeoLab 5 and the Linkwitz Lab “Orion.” They are the two best speakers known to me at this juncture, but that doesn’t necessarily mean there aren’t others. I shall try to explore the newer electrostatics, full-range ribbons, powered dynamics with electronic crossovers, etc. Some are not so easy for a reviewer to obtain on loan, especially if he isn’t one of those thinly disguised handmaidens of the industry. We shall see. At any rate, I am through with monkey coffins.
21 October, 2006
A Fraud that Anyone with Common Sense Can See Through
Longtime readers of The Audio Critic are fully aware that many of high-end audio’s articles of faith are bogus. Most of these fraudulent pronouncements about cables, tubes, vinyl, etc., require a little bit of engineering science to refute. A typical example is the absurd practice of biwiring, whose futility is made obvious by the superposition principle, a law of physics not known to everyone (see under downloadable Sample Articles, “The Ten Biggest Lies in Audio,” on this website).
There is one particular audio fraud, however, that requires no science but just ordinary common sense to see through. I’m talking about power cords—yes, those short lengths of flexible insulated cable that go between your wall outlet and your audio gear. The big lie is that they hugely affect the sound. The ads tell you that if you pay $499 or $995 or some such insane amount for a specially designed super cord, you will get a bigger soundstage, better transients, tighter bass, smoother highs, etc., etc., blah, blah, blah. Amazingly, quite a few nonthinking audiophiles with deep pockets buy these fantasy cords.
Now, just think about it. The AC current comes into your residence over miles and miles of wire. After it enters the walls of your house or apartment, it again traverses huge lengths of BX cable or similar wiring. After it comes out of your wall outlet through the power cord and enters your amplifier or other equipment, it again goes through a maze of wiring before activating the devices that affect the sound. So, tell me, how does the electricity know where the nondescript lo-fi wiring stops and the super wire—just six feet of it—starts and leaves off? Does the current say, hey, I’m coming out of the wall now, the next six feet are crucial? Come on. The power cord represents an infinitesimal fraction of the AC current’s total path. Even if the wire in the power cord were so much better, it would have to be stretched all the way back to the power station to make a difference! It’s pure bull on the face of it; no science needed. The fact is that any power cord rated to handle domestic AC voltages and currents is as good as any other. The power cord that came with your amplifier or receiver will give you optimum performance. If you have to buy an extra one, just make sure it’s thick enough in gauge for heavy-duty equipment. If you pay more than a few bucks, you’ve been had. (Besides, as I’ve stated a number times before, your audio circuits don’t know and don’t care what’s on the AC side of the power transformer. What they’re interested in is the DC voltages they need. But that’s engineering science…)
09 October, 2006
8-Channel Digital Power Amplifier
Designed by AudioDigit (www.audiodigit.com) in Italy. Manufactured by Autocostruire di Melani Antonella, Via A. Modigliani 27/B, 51100 Pistoia, Italy. Voice: +39 335 290925. Fax: +39 0573 31018. E-mail: email@example.com. Web: www.autocostruire.com. AudioDigit MC8x100 eight-channel “digital” power amplifier, 480 euros (c. $610) plus shipping and import duty. Tested sample on loan from manufacturer.
As I have stated before, I’m not really interested anymore in testing parity products (such as, let us say, the 217th multichannel receiver to come on the market) but would greatly prefer to explore new and different, or at least unconventional, designs that point to the future. I was very excited, therefore, to discover on the Internet this strictly 21st-century low-cost amplifier from Italy. It uses special audio-amplifier IC’s manufactured by Tripath Technology Inc. of San Jose, California, which employ a technology Tripath calls Digital Power Processing. DPP-based amplifiers are “Class-T” designs, which are not quite like class D pulse-width-modulation amps but still have similar modulated switching carrier outputs. The claimed benefit is tremendous power efficiency without any tradeoffs in audio quality plus unequaled power/size ratio. I asked for and obtained a review sample of the amplifier, possibly the first Italian MC8x100 to reach the United States.
The amplifier uses two Tripath TAA4100A four-channel Class-T audio amplifier IC’s, for a total of eight channels. This IC was originally designed for automotive head-unit applications, and pressing it into service to drive domestic high-fidelity speakers is a bit of a stretch, but that was the Italians’ idea. A single toroidal transformer feeds all circuits. The entire eight-channel unit is 17½" wide, which is standard, but only 2" high and 9½" deep. It weighs just a little over 13 pounds. Not even Bob Carver’s famous magnetic field amplifiers of the early 1980s, considered disturbingly small and light by the high-end audiophile press, achieved this kind of size reduction. The amplifier has no controls of any kind, just an on/off switch. There are eight unbalanced RCA-jack inputs and eight speaker connectors of the type that accepts banana plugs, bare wire, or spade lugs. Unfortunately, the binding posts are just a tad too widely spaced to accept dual banana plugs; this is some kind of European hang-up about safety. (They have AC plugs whose dimensions fit the standard dual banana jacks—only an idiot would plug one of these into an amplifier’s output.). Class-T operation isn’t really digital in the sense that 0’s and 1’s are processed in the signal path, but the waveform before the output filter is a complex “digital” waveform (i.e., pulses) of varying frequency. By contrast, the corresponding waveform of a class-D PWM amplifier is fixed in frequency (generally between 100 kHz and 200 kHz). The difference lies in the architecture of the Tripath IC, which we won’t go into here (it involves DSP and “predictive processing,” among other things). The chief benefit is claimed to be power-conversion efficiencies of 80% to more than 90%, while yielding audio quality approaching class A and class AB. (I said, “claimed to be.”)
The frequency response of two of the eight channels, at 1 watt into 8Ω, is shown in Fig. 1. The bass rolloff starts at a higher frequency than is normal in standard high-fidelity amplifiers. Down by more than 0.4 dB at 20 Hz is not a very good spec. As for the 0.36 dB rise at 20 kHz, it is almost certainly inaudible but also abnormal. Our analog expectations may be too sanguine in the case of this “digital” amplifier. Let’s not exaggerate, though; this is still a very acceptable frequency response.
Fig. 1: Frequency response of channel 1 (cyan) and channel 5 (red) at 1 watt into 8Ω.
The distortion curves depart significantly from the one in the instruction manual. That one bottoms out at 0.009% (–81 dB) with a 1 kHz input into a 4Ω load and clips at 45 watts, with very high-distortion output available up to 110 watts. My measurement of the same frequency into the same load shows an absolute minimum at –72 dB (0.025%), clipping at 40 watts (in the better of two channels), and maximum available output of 61 watts at sky-high distortion. Big difference. This is basically a low-powered amplifier. (The word I have from Italy is that the power supply in my test sample was set at a lower voltage, for safety reasons, than the one belonging to the amplifier spec’d in the manual.)
Fig. 2 and Fig. 3 show the THD+N into 8Ω and 4Ω, respectively, at three different frequencies each, for two of the eight channels. Radical filtering above 20 kHz was applied to remove all out-of-band noise, since the out-of-band switching carrier components invariably affect the accuracy of the measurements. That is the reason for the change to 6 kHz from the usual 20 kHz as the highest test frequency; the second harmonic (12 kHz) and third harmonic (18 kHz) are included that way, whereas the use of a 20 kHz fundamental would be meaningless. As can be seen, the curves are pretty much clustered together and stay below –60 dB (0.1%) at all levels, except the 20 Hz curves, which are quite horrible. This amplifier is incapable of genuinely clean 20 Hz output beyond a couple of watts. Maybe the assumption is that a multichannel system driven by the amplifier will have a separately powered subwoofer.
Fig. 2: THD+N vs. power of two channels into 8Ω. Channel 1: 20 Hz (red), 1 kHz (cyan), 6 kHz (magenta). Channel 5: 20 Hz (yellow), 1 kHz (green), 6 kHz (blue).
Fig. 3: THD+N vs. power of two channels into 4Ω. Channel 1: 20 Hz (red), 1 kHz (cyan), 6 kHz (magenta). Channel 5: 20 Hz (yellow), 1 kHz (green), 6 kHz (blue).I wanted to investigate the 20 Hz distortion further. Fig. 4 is the FFT spectrum of a 20 Hz tone at 10 watts out, the level of maximum distortion, into a 4Ω load. Two of the eight channels are shown. The curves prove that the high distortion consists largely of second harmonic (40 Hz) and third harmonic (60 Hz), with a little fourth harmonic (80 Hz) thrown in. Nothing mysterious or exotic there; this is absolutely classic low-frequency distortion.
Fig. 4: Spectrum of a 20 Hz tone at 10 watts into 4Ω, two channels (channel 1, cyan; channel 5, red).Channel separation, on the other hand, is very good indeed, as shown in Fig. 5. Even at 20 kHz, the crosstalk is of the order of –68 dB, and over most of the audio spectrum it is –80 to –98 dB. That’s right up there with the best. It needs to be pointed out, however, that I measured channels 1 and 5, which are on two separate IC’s. My test setup was wired that way, and I saw no compelling reason to change it. If I had measured two channels on the same IC, the results may not have been quite as impressive.
Fig. 5: Separation between channels 1 and 5 at 1 watt into 8Ω.
Finally, the PowerCube test was a total bust—not because of bad results but because it could not be performed. As I’ve explained many times before, the PowerCube test measures the ability of an amplifier to drive widely fluctuating load impedances. As far as I know, The Audio Critic is the only American audio journal to publish PowerCube measurements. The instrument for the test is made in Sweden; it produces repeated 1 kHz tone bursts of 20 ms duration into 20 different complex load impedances across the amplifier (magnitudes of 8Ω/4Ω/2Ω/1Ω and phase angles of –60°/–30°/0°/+30°/+60°). The graphic output of the instrument shows the 20 data point connected to form a more or less cubelike polyhedron. The test shows up the differences between otherwise similar amplifiers when it comes to real-world loudspeaker loads rather than just resistances. The AudioDigit amplifier went into protection in the earliest part of the test, on the 3rd of the 20 loads (–60°/2Ω). Obviously, the protection thresholds are set all wrong, in the expectation of 8Ω to 4Ω nonreactive, or mildly reactive, loads only. It is possible that the amplifier could draw a good PowerCube if the protection circuits were set differently.
As I have pointed out innumerable times, a properly designed amplifier has no sound of its own. It is impossible for two amplifiers to sound different at matched levels if each has high input impedance, low output impedance, flat frequency response, low distortion, low noise floor, and is not clipped. The MC8x100 is a special case because of its peculiar THD+N vs. power curves, allowing considerable high-distortion output beyond the clipping point. The expectation of some sonic anomalies is therefore not altogether unreasonable. For a quick check, I connected the amplifier to a pair of floor-standing wide-range speakers of decent quality (Sony SS-K90ED’s), with channels 1 and 5 feeding left and right. I thought I heard a few subtle, momentary sounds I didn’t like. An ABX comparison with a conventional amplifier of comparable power would definitely be in order. That takes time, and I want to post this already delayed review forthwith. I’ll do the ABX tests later and append the results here when I am done. (Don’t expect anything revelatory.)
The AudioDigit Class T-Amp MC8x100 is a minor technological tour de force—with warts. I decided not to use it between the electronic crossover and the eight drivers of my pair of Linkwitz Lab “Orion” speakers, which was my original plan before I did the measurements. There just isn’t enough power before clipping, and after clipping the bizarrely available power appears to be unacceptable because of high distortion. Too bad—I would have liked to tell the high-end fanatics that I am using a really cheap amplifier to drive a state-of-the-art loudspeaker. The amplifier may still be perfectly adequate in a surround-sound system using conventional speakers, but we’d better wait for the ABX tests to confirm that.
PS: No ABX Test
Well, I set up an ABX test. Very carefully. (The identity of the other amplifier is at this point irrelevant, as you will see.) When I switched on the AudioDigit amplifier, it started to smoke and smell, and blew its power-supply fuse. Removing the cover, I identified the cluster of power-supply capacitors as the culprit. They smelled smoky; the rest of the amplifier did not. I think what happened was that my line voltage was a little high that afternoon, and the amplifier could not take the turn-on surge. Of course, one or more capacitors could have been faulty to begin with. Maybe it was pure luck that the measurements could be completed. The rest of the equipment plugged into the same power strip—and that includes the other amplifier—did not bat an eyelash. Nor have I had a similar problem with any piece of gear in the 18 years I have lived in my house. Draw your own conclusions. The amplifier is going back to Italy. Maybe they’ll send me an improved version. I still think it’s a very intriguing design that breaks with the past and looks ahead.
09 August, 2006
A Note on NXT Distributed Mode Loudspeakers
This was an attempt to investigate the high-fidelity possibilities of a radically new and different transducer technology.
NXT is a fairly young but rather large company based in Huntingdon, England. They are responsible for the development of the Distributed Mode Loudspeaker (DML), which is a flat-panel transducer that can assume innumerable different shapes and forms, both opaque and transparent, and is not based on the piston concept but on bending-wave physics. A DML panel vibrates in a large number of modes instead of moving back and forth as a rigid piston-like unit. I have never seen a formal mathematical analysis of the basic design, but there are literally hundreds of products out there, large and small, using the NXT patents, from “talking” TV screens to cheap little surround-sound satellites. Everything except high-end audio—and I wondered why. (Actually, I witnessed a CES demo of a high-endish prototype a few years ago, but it never flew.)I managed to get my hands on a two-foot by one-half-foot transparent NXT panel, which had been part of a discontinued mass-brand compact music system. I know that this panel does not represent the state of the art in DML technology, but it was intended to reproduce music and therefore promised to give me a minimal indication of the hi-fi possibilities of the DML concept. I connected it to my bench amplifier (no EQ, as there may have been in the commercial system) and set it up to run a frequency-response curve with the MLS (quasi-anechoic) method. The result is shown in Fig. 1.
Fig. 1: Frequency response at 1 meter on axis (amplitude blue, phase green).
As can be painfully seen, the response is horrible—so horrible, in fact, that I do not believe it. It is possible that the bending-wave/multimodal sound propagation cannot be accurately measured with the MLS method. I am just speculating because, as I said, I have not seen a formal analysis of the system. Maybe some kind of averaging measurement at a large number of points would be more valid. I just don’t know. My reluctant conclusion, tentative as it is at this juncture, has to be that the hi-fi potential of the DML concept is extremely limited and that the absence of high-end applications is inevitable. I hope to change my mind if and when contrary evidence becomes available to me.
18 July, 2006
Back to CD/SACD Reviews
As our regular readers know, I am neither a professional musician nor a tweako audio cultist. You won’t find either one of those perspectives here. I just listen to CDs (mostly classical), look at and listen to DVDs (mostly opera), and pick a few interesting ones for my brief and modestly offered reviews here. The assumption is that music-loving audiophiles and audio-savvy music lovers will find at least some of my stuff worth reading because I try to engage them on their level.
CD from/by The Fry Street Quartet
Ludwig van Beethoven: String Quartet in A Major, Op. 18, No. 5; String Quartet in A Minor, Op. 132. Igor Stravinsky: Three Pieces for String Quartet (1914). Ned Rorem: String Quartet No. 4 (1994). J. Mark Scearce: String Quartet 1o (Y2K). The Fry Street Quartet (Jessica Guideri, violin; Rebecca McFaul, violin; Russell Fallstad, viola; Anne Francis, cello). FSQCD3 (2 CD/SACDs, 2004).
If this release had come from Sony BMG or Deutsche Grammophon or EMI, there would have been a lot of rave reviews by now. But since it was self-published by The Fry Street Quartet, it attracted no attention from music critics, at least the critics I keep track of. Too bad, because in my humble opinion (IMHO is the oh-so-hip Internet shorthand) these discs are both an artistic and an audio event. The Fry Street Quartet is right up there with the best, both technically and musically, and Ray Kimber’s IsoMike technique, used here for the first time in a full-length classical release, appears to be a significant step up from conventional miking approaches. I say that knowing full well that Ray Kimber’s main business is selling obscenely overpriced fantasy cables to gullible audio neurotics. His recording of a string quartet, on the other hand, is simply the best I’ve ever heard, surpassing even the best work of Max Wilcox and John Eargle. The sound has a lifelike presence, effortless fullness, and natural resonance unequaled in my experience. IsoMike (“Isolated Microphones”) is a system that separates the recording microphones by means of huge, oddly shaped baffles of complex mechanical design (see www.isomike.com). How and why this works need not be discussed here, but the resulting acoustic detail is uncanny. The DSD recording uses 4.0 channels, but I liked the plain stereo layer best through my Linkwitz Lab “Orion” speakers. The rear channels contribute relatively little. As for the music, the Beethoven Op. 132 is one of the pinnacles of Western art, a desert-island Top Twenty, completely dwarfing the quite wonderful but very much earlier Op. 18, No. 5; the Stravinsky piece is a short exercise in Sacre-like rhythms and sonorities, mighty stylish; the Rorem quartet is a highly listenable romantic/acerbic “Pictures at an Exhibition,” this time anent ten paintings by Picasso; the Scearce quartet is reminiscent of Bartók without the latter’s originality and loftiness of purpose. Throughout, the ensemble playing, phrasing, and tone of the Fry Street Quartet are on the highest professional level, in a league with the big-name quartets of the world. That the FSQ is three quarters female has an effect on their style (again, IMHO); their playing is simply beautiful rather than pointed. I am fully aware that this exposes me to the wrath of feminists who don’t believe in vive la différence! At any rate, this recording is a major sleeper.
CD from Harmonia Mundi
Frédéric Chopin: The Complete Waltzes. Alexandre Tharaud, piano. HMC 901927 (recorded 2005, released 2006).
I knew it. If anyone was going to rival the Dinu Lipatti 1950 and Artur Rubinstein 1963 recordings of the Chopin waltzes, it would be Alexandre Tharaud. He is the young French pianist of impeccable taste and superior intellect whose Ravel recording I raved about a while ago and whose name ought to be a lot more famous than it is. (Not that great Ravel playing automatically implies great Chopin—it did not, for example, in the case of the fabulous Ravel interpreter Walter Gieseking—but what we have here is the French Connection!) On this CD Tharaud presents all 19 of the waltzes, including the 6 posthumous opuses, in a nonchronological sequence that constitutes a neatly balanced one-hour program. His technical fluency, his carefully judged rubato, his elegant yet often passionate phrasing, his dynamics are all on a level that, to my ear, threatens to set a new standard. The Grande valse brillante, Op. 34, No. 1, had me wildly applauding the CD player! I have a theory that the very best efforts of the present, in any field, inevitably surpass the best efforts of the past. Roger Bannister ran the mile faster than Paavo Nurmi, and Hicham El Guerrouj runs it a lot faster than Roger Bannister. Time marches on; techniques are refined; benchmarks are reevaluated; nothing is sacred. I think that Tharaud probably has a better intellectual grasp of what the Chopin waltzes are all about than previous generations of pianists. Sue me if I’m wrong. As for the audio, the sound of the piano is as good as it gets; the correct setting of the volume control brings the Steinway D right into your room. In every way, a triumph!
CD from Naxos
W. A. Mozart: Eine kleine Nachtmusik (Serenade in G Major), K. 525; Serenata notturna, K. 239; Divertimento in F Major (Lodron Night Music No. 1), K. 247. Swedish Chamber Orchestra, Petter Sundkvist, conductor. 8.557023 (recorded 2004, released 2006).
“Eenie kleenie” used to be everybody’s introduction to classical music, including mine. It is hackneyed, yes, but still a gem, full of unforgettable melodies and possessing great formal structure. Amazingly, I’ve never had the opportunity to write about it; this is the first time. This version is exactly right, played by a double or at most a triple string quartet plus one contrabass; the piece sounds bloated and unnatural when the whole string section of a huge symphony orchestra plays it. Basic Mozart doesn’t require great virtuosity to be played elegantly, just some taste, musicality, and an understanding of style. The Swedish Chamber Orchestra has all those qualities in abundance. You don’t need a better performance, even if better ones exist (after all, the competition is huge). The gorgeous stereo recording reinforces that conclusion, presenting a thoroughly palpable soundstage and superb string sonorities. The other two serenades fall short of immortality, being much earlier Mozart, but that doesn’t mean they aren’t utterly delightful. The man was, from day one, genetically incapable of composing mediocre music. K. 239 has some startlingly colorful instrumentation in the last movement, with flashy timpani rolls. K. 247 has some lovely passages for two horns. When he was not being original, Mozart was merely beautiful. His music is sometimes transcendently great, sometimes just routinely wonderful, never negligible.
SACDs from Ondine
Bohuslav Martinu: Memorial to Lidice, H. 296. Gideon Klein: Partita for Strings (arr. Saudek). Béla Bartók: Concerto for Orchestra, Sz. 116. The Philadelphia Orchestra, Christoph Eschenbach, conductor. ODE 1072-5 (2005).
The great Philadelphia Orchestra, my special favorite, had to go to a Finnish label to have its new recordings published and marketed—a sign of the times. No special recording sessions, either; all releases are edited from live recordings of scheduled concerts in Verizon Hall. The centerpiece of this CD is the Bartók, which at 63 years old is—believe it or not—the youngest composition to become a regular repertory item of every major orchestra in the world. Nothing composed even 50 years ago is played as regularly, over and over again. Amazing. The Bartók, Martinu, and Klein pieces were all composed within a few months of each other, in 1943-44, which appears to be the “album concept” here (as if we needed one). The latter two did not become repertory items—I give you three guesses why. They’re moderately interesting and beautifully performed by Eschenbach, and that’s that. The Concerto is of course a masterpiece, fully deserving its fame, with superior performances under every major conductor of the 20th century in the catalog. Reiner/Chicago 1955 is still considered a benchmark; it combines authenticity, intensity, elegance, virtuosity, and great sound by Lew Layton—all in all, hard to beat. Eschenbach presents a 21st-century performance, in which all the traditionally emphasized Bartókian savagery has been subsumed under a more comprehensive scheme of balance, structure, transparency, and sheer beauty. It becomes clear that the music is no longer “modern.” The exquisite Philadelphia woodwinds, the golden brass, the plush strings seem to imply that a gut-wrenching approach would be downright vulgar. I find this level of orchestral playing utterly disarming—“do anything you want” is my emotional reaction. Eschenbach totally sells me gorgeous Bartók over exciting Bartók. Such is the power of a stupendous orchestra under a strong-willed conductor. Not that certain passages are lacking in excitement; the last-movement presto, for example, is taken at breakneck speed, almost flirting with danger. The recorded sound is also magnificent; the tunable hall’s resonance chambers are in finer adjustment than in the Sawallisch/Schumann recordings I reviewed some time ago, and everything is in superb balance. That goes for the stereo layer as well as the SACD 5.1-channel layer, which for once provides excellent localization and envelopment. You should own more than one recording of this piece, and this should be one of them.
Peter Ilyich Tchaikovsky: Symphony No.5 in E Minor, Op. 64; The Seasons, Op. 37b (January-June). The Philadelphia Orchestra, Christoph Eschenbach, conductor & piano (in The Seasons). ODE 1076-5 (recorded 2005, released 2006).
I looked forward to this release because in March 2006 I heard a very beautiful performance of Tchaikovsky’s Fourth Symphony at the Kimmel Center by the Philadelphia Orchestra under Eschenbach. Their recording of the Fifth is a disappointment. The orchestral playing is magnificent, as usual, but Eschenbach’s concept of the symphony departs radically from my musical expectations. A tight, sinewy, fairly swift performance, as in Mravinsky’s unforgettable 1960 recording on Deutsche Grammophon, still preserves all the romanticism of the music because it’s built into the score; indeed, the romantic phrases remain more coherent if you don’t slow them down but get on with it. Eschenbach lingers meltingly over every lovely phrase, producing an almost whiny effect. His performance is 50½ minutes long as against Mravinsky’s 43! Admittedly, there’s more than one way to skin a cat, especially when it comes to Tchaikovsky, but Eschenbach’s way is too much for me. (I’m reminded of the great—and notorious—Willem Mengelberg’s precept: “In Tchaikovsky, everysing a leettle exagéré.”) The relatively lightweight Seasons, for piano solo, is tossed off prettily and unpretentiously by Eschenbach, but why play only the first 6 of the 12 pieces? Because that’s all that fits on the CD after the symphony? Come on! As for the recorded sound, the stereo layer is not quite as precisely delineated and transparent as in the Bartók recording above, with somewhat attenuated highs and slightly congealed climaxes. The balance engineer was not the same on an otherwise identical recording team, which could be the reason. In this case I actually prefer the SACD multichannel layer through my Waveform home-theater system because the climaxes are cleaner, and both the localization and envelopment are excellent. (Can’t each layer be totally optimized?) I would rate this whole effort on the low end of the scale for the three Phidelphia/Verizon Hall recordings released so far.
07 May, 2006
Floorstanding 3-Way Loudspeaker System
Canton Electronics Corp., 1723 Adams Street NE, Minneapolis, MN 55413. Voice: (612) 706-9250. Fax: (612) 706-9255. E-mail: firstname.lastname@example.org. Web: www.cantonusa.com. Vento 809 DC floorstanding 3-way loudspeaker system, $5000.00 the pair. Tested samples on loan from manufacturer.
Canton is not a Chinese brand, the name notwithstanding. The speakers are made by the Canton Elektronik company in Germany and distributed in this country by the company’s U.S. affiliate. Even the earliest print issues of The Audio Critic, back in 1977, contained some Canton reviews, but the Vento Series is relatively new.
As readers of this Web ’zine know, I am not very interested in “monkey coffins” anymore (a monkey coffin being a rectangular box with passively crossed-over forward-firing drivers), and the Vento 809 is still basically a monkey coffin despite its gracefully rearward-curving sides. So why am I reviewing it? Mainly because it’s roughly the same size at the same price with the same number of drivers as my Linkwitz Lab “Orion” reference speaker, and by contrast it’s quite conventional in engineering. A valid comparison of good standard vs. maverick design.
The Vento 809 is a little under four feet high and takes up less than a square foot of floor space. Its horizontal cross section is two thirds of an ellipse with the tip chopped off. The bass-reflex enclosure houses two 8" aluminum-cone woofers, a 7" aluminum-cone midrange, and a 1" aluminum-manganese dome tweeter. The crossover frequencies are 250 Hz and 3 kHz. The cabinet, made with a multilayer lamination process, is exceptionally solid and acoustically dead. Two pairs of terminals are provided for biamplification, which has certain advantages, or biwiring, which is utter nonsense. Unfortunately, the manual does not make that distinction—the tweako/cultist tradition is honored.
I took three quasi-anechoic (MLS) frequency-response curves at a 1-meter distance: on the tweeter axis (Fig. 1), 45° off axis horizontally (Fig. 2), and 45° off axis vertically (Fig. 3). As I have pointed out before, quasi-anechoic measurements with the Maximum Length Sequence technique are not as reliable and accurate as measurements made in an anechoic chamber or outdoors under windless conditions. The former, however, are a lot faster and more convenient, and they indicate the overall trends more than adequately for our purposes. What are those trends in the case of the Vento 809? Not good, I’m afraid. The three curves clearly show that the power response into the room is rather heavily skewed toward the higher frequencies, from about 2 kHz on up. Below that frequency the response is reasonably flat; above it there’s a lot more output no matter where the measurement microphone is placed. This is not a peak but an excess of energy distributed over several octaves. If the only problem is that the tweeter is set too high (“I vant more brilliantz, Helmut”), it’s easily remediable. As it is, it’s highly audible (see below).
Fig. 1: Frequency response (amplitude blue, phase red) at 1 meter on tweeter axis.
Fig. 2: Frequency response (amplitude blue, phase red) at 1 meter 45° off axis horizontally.
Fig. 3: Frequency response (amplitude blue, phase red) at 1 meter 45° off axis vertically.
The bass response can be accurately measured with the nearfield technique (originally developed by our sometime contributor Don Keele). Fig. 4 shows the nearfield response of the two woofers and the bass-reflex vent. The curves are highly accurate from 100 Hz on down. Fig. 5 shows the summed nearfield curve, taken at a point experimentally determined to yield the flattest and deepest response. It appears that the box is very loosely tuned to around 32 or 33 Hz and that the –3 dB frequency (f3) of the summed response is 42 Hz. The –6 dB frequency, generally considered the limit of bass response, is 38 Hz. I expected deeper bass from a $5K-a-pair loudspeaker.
Fig. 4: Nearfield frequency response of the two woofers (blue and red) and the vent (magenta).
Fig. 5: Overall nearfield bass response.
Fig. 6 shows the distortion products of a 45 Hz tone played at a 1-meter SPL of 96 dB. That’s the lowest frequency within the ±1 dB flat response of the speaker, and 96 dB is about as loud as it gets that low in the bass. The 2nd harmonic (doubling) distortion is –35 dB (1.78%), the 3rd harmonic –53 dB (0.22%), the 4th harmonic –72 dB (0.025%), the 5th harmonic –60 dB (0.1%), the 6th harmonic –73 dB (0.022%), the rest totally negligible. I would call that an excellent result, confirming the quality of the 8" drivers. Generally, bass distortion is by far greater than midrange or treble distortion, so this is the only THD measurement I took.
Fig. 6: Nearfield spectrum of a 45 Hz tone at a 1-meter SPL of 96 dB.
The impedance of the Vento 809 is shown in Fig. 7. (Ignore the curves below 35 Hz; they are irrelevant.) The magnitude dips as low as 3.4Ω at 45 Hz and 130 Hz, and peaks to 9Ω at 67 Hz and to 7.1Ω at 1.35 kHz. The phase fluctuates between –35° and +21°. Any half decent amplifier can happily drive a speaker with that impedance.
Fig. 7: Impedance magnitude (blue) and phase (red).
Speakers that measure poorly but sound great exist only within the pages of Stereophile. The Vento 809’s excessive output of high frequencies above 2 kHz is not only measurable but readily audible. If a recording is on the bright side to begin with, its reproduction through the Vento 809 will be downright unpleasant. If it is a well-balanced recording, it will merely sound overbright. The effect is most obvious on axis but is still clearly perceptible no matter where you sit. By contrast, the Linkwitz Lab “Orion” is gorgeously listenable on recordings with a wide range of brightness; they will simply be reproduced with varying degrees of presence. (Of course, the Orion doesn’t really “exist” in the commercial sense.)
As I suggested above, the fault may be only skin-deep; perhaps the tweeter just needs a little more padding. The speaker appears to be well-engineered overall; the bass is on the light side but the sound is quite transparent and spatially detailed. I really doubt if the engineers are responsible for the exaggerated high frequencies; they know better. Probably some higher-up decision maker wanted that sound for marketing reasons, thinking it will sell better. (Jawohl, Herr Generaldirektor!) He overlooked the fact that the Vento 809 is not a kitchen radio. I seem to remember that the Canton speakers I reviewed in 1977 were also overbright. Corporate culture?
Pad out that tweeter, Ingenieure, and send the speaker back to me. (Fat chance…) I think I’ll like it then.
13 April, 2006
Your Editor, Revealed
An Unprecedented Interview
Editor’s Note: The following interview was conceived, produced, and edited by a longtime subscriber to The Audio Critic who wishes to remain anonymous. It was conducted by e-mail over a period of a few weeks in March/April 2006. The questions were entirely the interviewer’s choice; your Editor merely answered them as best he could.
In 1977 I came across an advertisement within the pages of the erstwhile Audio magazine, an advertisement for a new audio publication promising reviews of high-end gear based on a kind of technical competence not found elsewhere. The price seemed high, but who could resist? I sent my check never expecting that, almost 30 years later, I’d still be reading. Over the years I purchased equipment based upon the Editor’s recommendations, never dissatisfied. And over the years, although the format changed, editorial standards set forth for all to read in Volume 1, Number 1 were maintained. Equipment reviews were factual, and presented with a unique and literate flair not found elsewhere. As time passed I often wondered about the man responsible for The Audio Critic. I knew what he thought about audio but I never really knew much about him as an individual—that is, his background and the thinking leading him to publish The Audio Critic. In any case, my own thinking evolved as I read the Editor’s writing, and the writings of his contributors.
After reading his musings on the audio scene as he reflected upon what it all meant, especially in anticipation of his 80th birthday, I decided to track him down. My idea was that, to commemorate his birthday, he ought to put down in his own words his personal story for the benefit of his readers. Once I’d caught up with him he told me he was, frankly, not interested. His view was that The Audio Critic’s purpose was to highlight the audio scene. It was about music, the equipment we use, and the technology. It was not about him. Nevertheless, I was persistent—more persistent than I had a right to be—and he finally decided to give it a go. Thus it is, after all these years, we finally have our Editor, Peter Aczel, the man, in his own words, and within his own pages.
Finally, a brief disclaimer regarding what you are about to read: I am no technologist, nor am I associated with anything or anyone related to the audio industry. I am simply a longtime subscriber. The questions are my own, and the Editor had no input or foreknowledge about what I asked. However, he candidly answered whatever I put to him. The questions cover a variety of topics and, while they may not be questions you would ask, they were questions that, for me, I always wanted to ask.
Q. Some time ago you published a very funny cartoon that, in many ways, captured the irony of the hi-fi scene. It featured an audiophile with a very expensive “high-end tweako” system demonstrating it to a music-loving acquaintance. After the listening session ended, the gearhead wanted to know his friend’s opinion. The music lover thought a minute, then replied, “He conducts it a lot faster than Bernstein, doesn’t he?” Since oftentimes the music seems to take a back seat to the equipment, but since the music is really what our hobby is all about, I thought it might be best to begin by asking you about your early musical influences.
A. When I was eight years old, in Hungary, my mother decided I should have piano lessons. She sent me to a minor-league concert-pianist lady (the mother of one of my elementary-school classmates, actually), who turned out to be an unpleasant and unpersuasive teacher. I hated every minute of it. I was then switched to an amateur pianist lady, who was on the other hand a wonderful teacher. She had me playing simple pieces by Schumann and Bartók (this was in the mid-’30s!) in no time. She even took me to a children’s concert where a women’s chamber orchestra played Eine kleine Nachtmusik and Béla Bartók himself played some of his Hungarian folk-song arrangements on the piano. No big deal, just one of the two greatest composers of the 20th century noodling around on the piano to entertain the kids. (The other, Igor Stravinsky, was I am sure too stuck-up to have done the same. Besides, Bartók was also a world-class pianist; Stravinsky wasn’t.) By then I was hooked on music for life. By the time I left Hungary for the USA at the age of 13, I had been to the opera numerous times and tried to catch every classical-music broadcast on the radio. In the USA I started to collect 78-rpm shellac records, sporadically paid for out of my very meager allowance and played on an absolutely miserable portable phonograph with steel needles. At 16, my favorites were Wagner’s “Magic Fire” (Philadelphia/Stokowski) and Beethoven’s Op. 132 string quartet (Budapest Quartet). From there on, my musical development was more or less inevitable.
Today, a child not only attending the opera but enjoying it, is a bit out of the ordinary. Was this kind of “classical education” typical at the time? Also, were there any particular performances that made a lasting impression on you?
It wasn’t altogether typical, but there were a lot more kids who enjoyed classical music than in today’s hip-hop generation in America. Among the performances I remember, there was a Rigoletto with the almost forgotten world-class tenor Kálmán Pataky singing the Duke, and of course the Béla Bartók concert I have already talked about.
You came to the US in the late ’30s? Was this due to the political situation in Europe?
Yes and no. My father was the managing editor of a liberal daily newspaper in Budapest (not excessively left-wing, actually). When Hitler occupied Austria in 1938, he said, “This is it, it’s all over for Europe.” We had a good life and could have stayed there for a number of years, but he decided, with a good deal of prescience, to take the family to the United States, where he had sisters living since the 1920s. In 1944, after the Germans had occupied an insufficiently cooperative Hungary, the Hungarian Nazi thugs had free reign and turned the country into a nightmare. The entire staff of my father’s not-very-left-wing newspaper, without exception, ended up in a concentration camp. It wasn’t a death camp, and they all came back after the war, but most of them were walking skeletons. So my father ended up having been right, and how!
Most audiophiles recall the first time they heard hi-fi sound. It is usually a defining moment and one that sets in motion a desire to pursue the hobby. Can you tell us about the first time you experienced high fidelity sound, and what impression this had on you?
It was in 1948, when I was 22. I went to an electronics show in New York and heard an early Magnecord tape recorder play a live recording of the Air Force Band through an Altec Lansing theater speaker. I was blown away. The sound had real-life dynamics and harmonic detail. I hadn’t thought until then that this was possible. Again, the consequences were inevitable.
What about your first stereo system?
I go much further back than the dawn of stereo. My first mono system was assembled in 1948 (shortly after the New York show experience) and consisted of an 8-inch Altec Lansing full-range speaker in a bass-reflex enclosure, a 10-watt all-triode amplifier designed by Consumer Research (the now-extinct rival of Consumers Union), a Meissner FM tuner (ever heard of it?), and a cheap record changer with an Astatic crystal pickup. I tried to figure out whether the dimensions of the ready-made bass-reflex enclosure were correct for the Altec Lansing driver; they seemed to be close according to the rudimentary Novak formulas (Thiele-Small came much later).
As a kid, were you an electronic tinkerer? Did you take things apart in order to see how they worked?
No, I was into chemistry. An 11-year old kid could walk into a pharmacy in those days (at least in Hungary) and purchase concentrated sulfuric acid or pure sodium hydroxide. If my mother had known what I was concocting in the bathroom, she would have had a fit.
Early on it seems that you were interested in the art (or should I say, science) of speaker design theory, and from your writing it’s evident that you’ve a pretty solid grasp of electronic theory. Are you self-taught? Did you learn all of this on your own, in your “spare time,” as they say?
Not quite. At Columbia College of Columbia University (Class of ’49) I majored in physics and mathematics, getting a good foundation in the scientific fundamentals. The specifically EE-oriented information I absorbed gradually on my own, prompted mainly by my interest in audio, but I knew from the start what an ohm and a volt and an ampere were, and I even had an adequate entry-level knowledge of calculus. The finer points of speaker design I became aware of only after getting involved with Ohm.
How did you become associated with Ohm Acoustics?
A self-taught audio engineer by the name of Marty Gersten had been fired by Rectilinear (a loudspeaker company that no longer exists) and needed a job. I was doing Rectilinear's advertising (on the side, not through my ad agency) and knew Marty from there. He had some interesting ideas about speaker design and persuaded me to make a small investment in a new loudspeaker company, along with a number of other partners. It was I who actually named the company.
You later reviewed the Ohm F. At the beginning of the review you stated up front that you had been, but were no longer, associated with the company. You came down pretty hard on the speaker, even though you admitted respect for the Walsh design theory. From a personal standpoint, was it difficult to show the kind of candor found in your review (that is, your highlighting all the speaker’s shortcomings), given your prior professional association with the company?
Not at all. By the time I was divorced from the company it was entirely owned by Tech HiFi, and the divorce had been rather unpleasant, although in the end I got a reasonably fair deal. Years later, when I did the review, I had no emotional ties to the company; furthermore, the Ohm F design ended up with huge compromises I had nothing to with.
When The Audio Critic arrived, there were three widely circulated audio magazines—Stereo Review, High Fidelity, and, to a lesser extent circulationwise, Audio. Of the limited distribution “undergrounds,” Gordon Holt published Stereophile, and Harry Pearson had founded The Absolute Sound. The contrast between the first group and the second was quite pronounced. When did you first get the idea that a new publication was necessary?
A friend suggested it. Underground audio journalism was in the air, an emerging phenomenon, and the existing undergrounds did seem a little bit fantaisiste. I was fed up with my career as an ad agency creative director, so I tested the waters. I ran a half-column ad in Audio with the headline “The Audio Critic is coming!” The ad promised equipment reviews based on measurements, not opinions. I got 1200 advance subscriptions before anyone saw the first issue. I quit my job and retired from Madison Avenue.
A friend first suggested you start The Audio Critic, and this seemed to you like a good idea? Forgive me if your answer sounds like you are glossing a bit. Surely there must have been more to your decision by way of background than simply picking up on a friend’s suggestion? After all, going from Madison Avenue to audio equipment reviewing is not a casual career decision.
I was fed up with Madison Avenue. I was looking for an excuse to quit. Initially I thought I would do The Audio Critic on the side, but when those 1200 subscriptions came in without anyone having even seen the first issue, I decided to take the plunge. At first it was exhilarating, but then in the 1980s, when the whole audio scene had slowed down and not much was happening, I actually tried to get back to Madison Avenue. I went to see my former boss, the great adman Ed McCabe (of Scali, McCabe, Sloves, later absorbed by the ever-larger corporate structures of the ad world), who said he considered me a very good copywriter but the business had changed and good writers were no longer needed. (He was right, too; look at today’s TV commercials). All in all, I think I had a better life sticking with The Audio Critic.
In your first issue you began a review of two dozen preamps. Most were paid for out of pocket—your pocket. How long did it take to actually get all of this gear together, and how long was it from your initial purchase until you could get the first issue out the door?
I started assembling the preamps in October 1976, and the first issue was mailed February 1, 1977.
What the hell did you do with all those preamps once you were finished with them?
I had an arrangement with a Long Island hi-fi store. I bought all the preamps from them, and they committed themselves to buying them all back at a reduced price. The spread wasn’t particularly great, but when multiplied by 22 it was still very good business for them.
After the public had digested the first few issues of The Audio Critic, you had pretty much polarized the audio scene. It seemed as if people either loved what you were doing, or they reacted with a kind of visceral animosity towards you, personally. Did you expect this kind of reaction, or were you surprised?
I always knew that audiophiles were emotionally challenged, but the intensity of their reactions did surprise me. After all, it wasn’t about the honor of their wives or the talent of their children or their next salary raise, but a freakin’ preamp, for crying out loud.
When it comes to hi-fi, most people usually think only of the end product—that is, how the music sounds in one’s living room. However, it was clear from early on that your interest was not merely one of end results but the entire recording chain. For instance, from day one you featured Max Wilcox as an associate editor. When did you first become interested in the back-end process, as opposed to the mere recreation of the recorded event in a domestic setting?
I was always aware of differences in recording technique, even in the shellac days, but did not give them too much thought until I had fairly high-resolution playback systems. It was a gradual process. Actually, it is only now, listening to my Linkwitz Lab “Orion” speakers, that I realize just how much better Lewis Layton was in the 1950s than nearly all recording engineers with their fancy equipment in the 21st century. It’s kind of depressing. By the way, I think the three greatest recordists of the modern audio era were Lew Layton, John Eargle, and Max Wilcox. There is a serious quality difference between their recordings and just about all others, to this very day. Some of the others are pretty good, but as Voltaire said, the best is the enemy of the good.
It is interesting that you quote Voltaire, a figure from the French Enlightenment, and a thinker who reacted strongly against the old scholasticism. If we view scholastic thinking as a way of holding up prevailing ideas based on faith, then we can contrast this with a new method where scientific thinking displaces a more naïve view of what has come before. The key, I think, is in method. You were always interested in formulating a precise methodological approach to reviewing equipment. In 1977 you discussed in print how listening tests should be conducted. For example, you wrote, “...you can’t compare the sound of something like, say, the Mark Levinson JC-2 and the DB Systems preamp by testing one unit in August and the other in November.” You then went on to discuss A/B testing in detail. Would it be wrong to conclude that, over the years, methodology has been your overriding concern in audio reviewing?
Audio reviewing comes down to method and not much else. Audio is in itself a method, a means to an end (which is reproduced sound in the listening room), and to evaluate a method without a methodology is an absurdity. What audio journalists without a methodology are engaged in is mere opining, not reviewing or evaluating. (Stereophile is a special case because they have a methodology but exhibit a total disconnect between their methods and their opinions.) I must add that all this was much more important in the early days of audio, when electronic signal paths were significantly different from one another and required a rigorous methodology for meaningful evaluation; today there is a convergence toward a single standard that makes comparative methodology more or less moot. I find myself using the ABX double-blind comparator much less often than I used to, because in most cases I know exactly what the outcome will be; of course, I still have to measure everything to make sure that I am not overlooking significant differences.
Long before you embraced A/B testing, it was clear that you had been seriously thinking about this as a means of comparing gear. Indeed, in the early days of The Audio Critic, you probably devoted more words to discussing this methodological approach than anyone in the audio press—and all this before you were actually conducting level-matched tests. Once you began precise level-matched testing, did you immediately come to a conclusion that all previous thinking had to be revised, or did your conclusions develop in a more gradual manner?
Actually, it was a coup de foudre, or almost. Someone had lent me a simple A/B switching box, without the possibility of level adjustments. I was trying to compare the sound of two completely different preamps which, by a huge coincidence, happened to have exactly the same gain. I couldn’t hear a difference! At first I firmly believed that the A/B box was covering up the difference, but upon further reflection that appeared most unlikely—totally passive, extremely short signal paths, no inductive or capacitive elements to speak of. It dawned on me that the two preamps must actually sound exactly the same. Paul on the road to Damascus... Of course, Mark Davis had told me years before that this is precisely the case, but I made fun of him in print. (Many years later, I met him at an Audio Engineering Society convention and apologized profusely. He didn’t even remember what I was talking about!)
Mark Davis used a pair of AR-11 box speakers and a Shure M-91E cartridge. You were using gear such as the Harold Beveridge electrostatic speaker and more expensive moving-coil cartridges. So at least there was a reasonable presumption that differences in results could have been related to source components. At the same time Davis was matching levels to within 0.3 dB; you indicated that you had level matched to about 1 dB. At the 0.3 threshold he claimed that “differences” were moot. Most audiophiles have absolutely no means to level match components, and hi-fi dealers are not going to do it for obvious reasons. So even though the psychoacoustic literature is clear, the average audiophile is left only with his or her experience. When presented with all the marketing baggage that comes with the territory, it is no wonder that things have not really changed much in the typical audiophile’s thinking. That leaves the burden of getting the message out to the press. You have written about this many times and offered your own reasons for the current state of affairs in audio journalism. Other than the fact that it is often difficult to change one’s way of thinking, is the bottom line simply that it would be bad for business if the truth were known and accepted?
Of course it would be bad for business, at least for the business of Halcro, Mark Levinson, Pass Labs, et al., whose astronomically priced products sound the same as a $200 Pioneer receiver. It wouldn’t be bad for Pioneer, but they don’t absolutely need the publicity of the high-end press. You are mistaken, however, when you say that most audiophiles have no means to level match. A very simple (and superbly ironic) method suggested many years ago by Larry Klein requires no instrumentation and no special expertise. Just play with the level controls of A and B until you can hear absolutely no difference between them. At that point the levels are matched within ±0.15 dB, guaranteed! I still groove on that one.
Your reviews were always different in style than anything else out there. The undergrounds often wrote pages and pages of mind-numbing verbiage. The major publications seemed like they couldn’t wait to finish a review, and they all pretty much read the same. Your style was a mix ranging from humor (the Janis subwoofer) to shock-and-awe total devastation (Infinity QLS). For the subscriber it all made good sense and interesting reading. Do you consciously try and mix your reviewing style for overall effect?
It depends on how I feel. Some audio components elicit from me the utmost seriousness, others contempt or pity, still others laughter. I don’t try to be consistent in my reviewing style. As Bismarck said, konsequent ist ein Ochs—an ox is consistent.
You often had at your disposal gear many audiophiles had heard of but had no reason to own. I’m reminded of your Levinson-modified Studer A-80—a deck one typically finds in a professional recording studio. In a response to a letter from a subscriber you mentioned you once owned Pearl microphones. I take it that over the years you’ve experimented with live recording?
Just a little, on a very few occasions. I don’t consider myself a recordist. That fancy equipment appealed to my gearhead side; the Studer/Levinson was mainly for playing borrowed master tapes. Anyway, nearly all amateur recordists are totally outclassed by the top pros, and I don’t like to be outclassed.
Nothing set apart The Audio Critic from the “undergrounds” like its contributors. I remember reading an issue of The Absolute Sound—it was an article by Enid Lumley. I actually thought it was Harry Pearson writing under a pseudonym in an effort to share some humor at his own expense. I thought he was just being funny... his way of telling everyone not to take it all so seriously. Only later did it occur to me that Ms. Lumley was an actual person, and that she was serious about whatever buffoonery she was writing about. The Audio Critic, on the other hand, offered writers like Richard Modafferi, David Rich, and guest articles by folks like Bob Adams. Occasionally, Stereophile will run an article by someone who knows what they are doing, but it all seems a bit out of place given their editorial slant. Now that your format has changed, do you foresee a place for third-party contributors?
Yes, Tom Nousaine and David Rich have already contributed, and I’m ready for others. The blog format, however, is much more casual and spontaneous than the print format, and I have less patience than I used to with the endless back-and-forth occasioned by contributors. As for Enid Lumley, I actually met her once on some audio occasion, and to my great surprise she treated me with the utmost deference.
No technology has created more misunderstanding and, frankly, more plain weirdness on the part of audiophiles than digital recording. We all agree that many of the first digital releases (both analog vinyl and CD) were not very good, sonic-wise. But time marches on and things change for the better. At the same time, some voices seem to have never recovered. To cite one example, Mark Levinson once went around (maybe he still does?) telling anyone who would take the time to listen to him that not only does PCM-encoded music sound bad, but it is bad for your physical health. This is clearly moonbat territory, and to a thinking person is clearly an embarrassment. On Mark’s Red Rose website (since removed) he was once thinking of hawking compact cassettes, clearly an inferior medium, inasmuch as, in his opinion, they sound better than CDs. Where do you suppose this disconnect from reality, among people who should know better, comes from?
There are people who are unable to change their opinion once they commit to it, even in the face of overwhelming evidence. Originally it may have been snap judgment, but then stubbornness sets in. Also, how do you know what Mark Levinson really hears? You’re not inside his head. He may have funny ears. I sometimes have the feeling that one particular person or another hears something totally different from what I hear. Of course, most of us hear pretty much the same thing and are able to come to an agreement, but some people... Do you think Rimbaud, with his dérèglement de tous les sens, would be an antidigital, CD-hating cultist today?
You are correct that no one can, strictly speaking, “get into another’s head.” But Mark, unlike Rimbaud before him, hasn’t abandoned his own poetic quest—the quest for good musical reproduction—and as long as he doesn’t take up gun running, I am fine. On the other hand, it seems to me that the idea of methodological investigation into the listening experience can determine, if not what the other feels inside, at least what the other can show on the outside—that is, what can be proved experimentally using controlled listening tests. To make a blanket statement that all PCM recording sounds bad, and that this is due to the PCM process, is strange. All it takes is one good recording to demonstrate that it is not the process that is at fault, but the application of the process. Does his musical city exist on the plain, and can he not find one good recording? When people confuse a general recording method with specific examples, a fallacy occurs. It seems that what Mark, and the others, are actually saying is simply that it is not pleasant to listen to a bad recording. And it is easy to fool oneself in these matters. I’m sure you’ve had the experience of listening one day and thinking all is well, and listening again another day, and thinking something is, if not quite right, at least different. But has anything really changed externally, or is it just the vagaries of our moods?
I agree with you totally that one good recording exonerates the process. There’s nothing wrong with Red Book, 44.1/16 CDs. When properly implemented, they can render absolutely lifelike sound. Some early 1980s CDs perversely incorporated LP-type equalization, which made them sound zippy. Mark Levinson appears not to have noticed that things have changed. As for things sounding good one day and not so good the next day, it’s probably due to volume changes. Peter Walker proved long ago that with a given recording played in a given room through a system with a given gain, only one setting of the volume control results in genuinely lifelike reproduction. Observing that rule could eliminate a lot of grief.
In the letters section, you once told the story of a man married to a lovely movie star, perfect to look at, but a woman he was unable to really get physical with. So, instead, he wound up consummating some hot action with a less visually attractive woman, but one he could definitely get his hands on. He was then happy. In a similar way, digital takes the audiophile out of audio; that is, one can hear, but one cannot touch. With records you can really fool around. You can change cartridges, adjust tone arm settings, worry about damping mechanical resonances, and so forth. Then, once done, you can actually see the thing spinning around in your living room. Due to the LP form factor, you can actually read liner notes and, at least in the old days, maybe hang a poster on your wall. It was all so interactive. Unfortunately, the sonic problems associated with vinyl remain. With CD you just plop the disc inside a black box and watch it disappear. There is nothing more to do. To a certain degree, could antidigital reaction simply be a tactile/psychological problem?
First, I have to correct you on that story (which of course was a fabrication to illustrate a point I was trying to make). The problem of the Hollywood sex symbol’s husband was that he could not concentrate on his pleasure while making love to her because, in his mind, he was constantly congratulating himself on his number one ranking on the erotic status scale. It had nothing to do with the tactile vs. nontactile issue. As for your question, I suppose some people need something to fuss with in order to love the whole process, but are these music people? I don’t think so. A genuine music person (and I consider myself to be one) would gladly just clap his hands and have superb music reproduction appear out nowhere without any equipment. And I say that even though I admittedly have a gearhead side.
I’d like to share an experience. Once, while listening to the Levine/Met Ring, I immediately became aware of something unusual, something I’d not really thought about before. The sound coming from my speakers had absolutely no background artifacts. With records, there is always something extraneous going on in the quiet passages. At a live performance there is always something in the background, even if it is just audience noise. On the various Bayreuth live recordings one hears stage artifacts, most notably within quiet passages. However, the sound of my “studio” Ring, while pristine, seemed almost artificial—artificial not because of what was there musically, but because of what was not there. Also, with, say, an LP record, dynamics are compressed. Yet, with the DGG Levine Ring I can listen at relatively loud levels in order to enjoy quieter passages. As the music grows louder, I must adjust the volume down. You speak of this latter situation in your review of Mr. Alexander’s recordings for Water Lily Acoustics. Could it be that PCM technology is, in a strange way, too good? Or is this maybe just an argument for more “live” recording, and recordings where the engineer, to use your words, employs a “judicious raising of the dynamic floor and lowering of the ceiling”?
Your Levine/Met recordings of the Ring sound a bit sterile because they were made in Manhattan Center (New York), which is an acoustically rather dead venue. In 1989, Max Wilcox produced a wonderful-sounding recording of the Mahler 5th (Mehta/NY on Teldec, released 1990) in that same Manhattan Center. He added some very subtle artificial reverb, which is not at all perceptible as such but makes the sound come alive. Now, compression is a highly complicated issue. The dynamic range of the human ear is more than 120 dB. The dynamic range of 16-bit digital recording is theoretically 98 dB. The difference between the absolute softest audible music in a concert hall and the loudest climaxes is of the order of 60 to 70 dB because of the ambient noise floor. Let us say you need 1 milliwatt of amplifier power, in a given installation, to play the softest passages (I am just guessing), then 70 dB above that would come to 10,000 watts. Any domestic loudspeaker would go up in smoke with that kind of input. With extremely high-efficiency horn-type theater speakers the numbers change; it is actually possible to produce levels of 110 or 115 dB or even more in a single installation, and here’s the remarkable thing—you can tolerate it because the distortion is low. We tend to judge loudness by the amount of distortion we hear, not by SPL! You wouldn’t adjust the volume control if you heard no distortion. So, you could have your “too good” 98-dB balls-to-the-wall digital recording without compression, if the efficiency and power-handling capability of your system were adequate—which they generally are not.
In a blog on the Bob Adams website he has an interesting but brief discussion of live sound versus recorded sound, our perceptions of the differences, and what this means for designers. When discussing what a recording ought to be, it is impossible to approach this question without having a model, or an idea of the form that the musical event should take in a domestic environment. There are those who argue that the goal of hi-fi is the recreation of the actual event in one’s living room. Setting aside the question as to whether this is even possible, I’d like to ask whether you think this is desirable? Let us not think right now about a symphony orchestra, but, even on a small scale, does anyone really want John Coltrane in their living room actually playing the saxophone? Inasmuch as the dynamics of just one instrument can be overpowering, should we not simply admit that what we really want is just a small—a very very small—illusion of reality, and not the reality?
Yes and no. I don’t mind at all having John Coltrane life-size in my listening room; my equipment can handle it. Single instruments, single voices, and very small instrumental/vocal groups can be reproduced as an actual event in a domestic environment, as long as the equipment is good enough. Of course, the illusion is still only 95% and not 100%, for reasons too numerous to discuss here. There is still the problem of whether the acoustics of the recording venue or of the listening room will prevail; in large listening rooms such as mine a somewhat dead recording can pick up the local acoustics; in small listening rooms there are problems with all but the “smallest” music. As for recreating a symphony orchestra or an opera-house performance in anything but a comparably large listening space, forget about it. The best we can hope for is an unobstructed window on the music, as if we were outside the concert hall or the opera, looking in through an enormous opening. (That model corresponds more closely to stereo than to surround sound, but for classical music a proper surround-sound recording is mostly stereo, anyway.) Also, don’t forget that a very good recording reveals more detail than one can hear from most seats in a dreadful concert hall like Avery Fisher Hall in New York’s Lincoln Center!
Have there been any particular items you wanted to review but, for whatever reason, never had the chance?
The latest incarnations of the Quad ESL (Models 988 and 989) have somehow eluded me; I never had a look at the famous Ionovac tweeter; I would have liked to test the Audio Artistry “Beethoven” speaker before it disappeared from the market because it was the largest-scale execution of the principles on which Siegfried Linkwitz based the “Orion,” my present reference speaker. It would also have been fun to look at the insanely priced power amps and preamps that Boulder switched to a number of years ago, because of the near-zero distortion, but I know that they wouldn’t have sounded different from “normal” equipment.
Thinking back, what three or four groundbreaking components changed the course of hi-fi, or your thinking about hi-fi?
The earliest Ampex and Magnecord tape decks because they demonstrated for the first time just what genuine high fidelity sounded like. The Dynakit 60 of the early 1950s because it was the first adequately powered high-quality amplifier at an affordable price. A. Stewart Hegeman’s Lowther-Brociner corner horn (c. 1951, also its plaster-of-Paris-and-plywood prototype) because no loudspeaker ever sounded as good before. The original Quad ESL, for obvious reasons. Bob Carver’s “Amazing Loudspeaker” because it was so amazingly clever (why did it have to disappear?). And, in a more fundamental sense, the Westrex stereo cutter head because it made stereo sound easily available in every home.
When The Audio Critic began, hi-fi was in its heyday. The Japanese offered relatively inexpensive gear for the masses, and there was a real excitement coming from the smaller “high end” manufacturers. In the mid-’70s the Pioneer Electronics company offered a wide range of integrated amps, FM tuners, even more receivers, and everything else in between. Their current lineup consists of six receivers and one modest integrated amp. Today, Yamaha makes only one integrated amp, and only one tuner. The market has definitely changed. On the other hand, in 2006, the emerging audiophile’s component of choice is likely to be the personal computer and whatever pocket appliance Apple comes out with. Home theater and television appear to have captured consumer imagination. In many respects those topics that were once so important, topics The Audio Critic wrote about, seem, now, to be surrounded in nostalgia. Do you think that the desire among consumers for the recreation of music in a home environment is waning? Are audiophiles as a distinct group becoming extinct?
I discern a distinct graying of the audiophile community. I think your 60-year old audiophile dentist still dreams about his next speaker system and is willing to spend money on it. The 20-year olds who used to build Dynakits are extinct. Between the computer and the iPod, their electronic thirst is quenched. The kind of music they favor doesn’t require very accurate reproduction, in any case. An altogether different trend, of course, is the home theater. When it comes to video with sound, I think the interest is at an all-time high.
Given what you describe, along with what you have written over the years, I guess we must conclude that the two most important people in hi-fi today are the recording engineer and the loudspeaker designer. As consumers, the former is really out of our reach. But, as you said, many audiophiles still think about their next set of speakers. At the same time, you’ve written that you’re a bit unenthusiastic when dealing with box speakers, yet this design remains most prevalent. I think I can speak for your subscribers in hoping that you have not “given up” reviewing more loudspeakers—even if they remain, to use your description, “monkey coffins.”
I think ordinary forward-firing dynamic drivers with a passive crossover in a closed rectangular box are boring! I can guarantee that no transcendent sonic experience can possibly be delivered by such “monkey coffins.” Decent sound per dollar, at best. Powered loudspeakers with electronic crossovers and DSP correction are another matter. I’m looking forward to testing that type of equipment, as well as electrostatics, ribbons, and other unconventional transducers.
05 April, 2006
2-Channel Power Amplifier
Parasound Products, Inc., 950 Battery Street, San Francisco, CA 94111. Voice: (415) 397-7100. Fax: (415) 397-0144. E-mail: email@example.com. Web: www.parasound.com. Halo Series A 21 stereo power amplifier, $1995.00. Tested sample on loan from manufacturer.
What? Another stereo power amplifier? Well, this one is a bit more review-worthy than most, even if it has been around for a while. It tries very hard to be “high-end audio” and to a large extent it succeeds, at about $3.85 a watt (into 8Ω), which is not unreasonable these days for an amplifier with pretensions not only in performance but cosmetics as well. This is a very good-looking product, and that plus its high power output (over 250 watts per channel into 8Ω) may be important to audiophiles who could buy a power amplifier of equal sonic capability for less money. Yes, all well-engineered amplifiers sound the same (if not clipped) but not all yield the same satisfaction of ownership.
The A 21 circuit was designed by John Curl, who is something of an icon in high-end audio circles; I vaguely remember him espousing some questionable tweako audiophile ideas years ago, but his basic expertise is not in question. David Rich, our former technical editor and circuit guru, muttered something about the open-loop JFET stage in the front end of the amplifier when he saw the circuit schematics; he didn’t think the 20 kHz distortion at full power could possibly be within specs as a consequence—but it is! (After all, it’s the black-box performance that matters.) This is a class AB amplifier; I was rather impressed by the heavy-duty output stage, sporting four pairs (4 × 2 = 8) of high-current bipolar Sanken transistors per channel, by the massive 1kVA toroidal power transformer, and by the amazingly open interior of the unit, consisting mostly of air and causing the cubic footage to swell to quasi-Krell proportions. Quality touches like double-sided printed circuit boards and Allen-head screws for the top cover abound. Even the sheet-metal front panel is shaped to simulate a solid machined piece à la high end. As I said, this is a high-end wannabe and it comes close. It even has both balanced and unbalanced inputs.
The quickest overview of a power amplifier’s performance is the PowerCube. As I’ve explained a number of times before, the PowerCube test measures the ability of an amplifier to drive widely fluctuating load impedances. As far as I know, The Audio Critic is the only American audio journal to publish PowerCube measurements. The instrument for the test is made in Sweden; it produces repeated 1 kHz tone bursts of 20 ms duration into 20 different complex load impedances across the amplifier (magnitudes of 8Ω/4Ω/2Ω/1Ω and phase angles of –60°/–30°/0°/+30°/+60°). The graphic output of the instrument shows the 20 data point connected to form a more or less cubelike polyhedron. The test shows up the differences between otherwise similar amplifiers when it comes to real-world loudspeaker loads rather than just resistances.
The PowerCube of the Parasound A 21 is shown in Fig. 1. It shows that the amplifier is utterly stable into all loads, regardless of impedance, but that its maximum dynamic output of 51.6 volts (which comes to 333 watts into 8Ω) is considerably reduced into 1Ω. That’s no big deal; 22.3 volts into 1Ω (which comes to 498 watts) is still far from puny; and, besides, negligibly few loudspeakers dip that low in impedance at any frequency. What’s more, the voltage/wattage into complex impedances is slightly elevated across board, which is the way it should be. All in all, a very decent PowerCube, with only moderate slope between 8Ω and 2Ω.
Fig. 1: PowerCube of one channel with both channels driven. The three axes are output in volts, impedance in ohms, and phase angle in degrees.
Fig. 2 shows the frequency response of both channels at 1 watt into 8Ω. It’s ruler-flat from 10 Hz to 10 kHz (down 0.04 dB) and –0.15 dB at 20 kHz. Can’t ask for more.
Fig. 2: Frequency response of both channels at 1 watt into 8Ω.
The “king of curves” in power-amp testing is distortion vs. power output. Fig. 3 shows the THD+N of one channel into an 8Ω load, both channels driven, with inputs of 20 Hz, 1 kHz, and 20 kHz. The measurement bandwidth was opened up to 80 kHz for the 20 kHz (red) curve to include the 2nd, 3rd, and 4th harmonics, so more noise was included as well, and therefore you can’t expect this curve to coincide with the other two. As can be seen, the amplifier clips at a little over 250 watts into 8Ω, just as the specs claim, and even at 20 kHz the full-power distortion is only –57 dB (0.14%), which again accords with the <0.2% specs. The specs’ claim of <0.03% (–70.5 dB) distortion at typical listening levels is well exceeded. These are not infinitesimal distortion figures (as boasted by Boulder, Halcro, etc.) but they are more than good enough from the standpoint of audibility. As for THD+N into 4Ω, I did not measure it this time because the PowerCube clearly showed that the 4Ω performance matched the 8Ω performance quite closely in every respect.
Fig. 3: THD+N vs. power of one channel into 8Ω, with both channels driven, at 20 Hz (magenta), 1 kHz (cyan), and 20 kHz (red).
I also looked at the FFT spectrum of a 1 kHz tone at full power into 8Ω, shown in Fig. 4. I wish the distortion products consisted almost entirely of 2nd harmonic instead of just about every multiple of the fundamental, but even so the measurement confirms Fig. 3 without tumbling major skeletons out of the closet.
Fig. 4: Spectrum of a 1 kHz tone at 250 watts into 8Ω, one channel.
The single-point noise of the A 21, with a measurement bandwidth of 22 Hz to 22 kHz and referenced to clipping level into 8Ω, was –111.1 dB and –113.5 dB, respectively, in the left and right channels. Those are superb figures.
Fig. 5 shows the crosstalk (i.e., separation) between the two channels at a level of 1 watt into 8Ω. The curves are somewhat unusual in that they bottom out at 500 Hz instead of reaching their minimum at the lowest end of the spectrum, but –70 dB or better at all frequencies, even the highest, and better than –90 dB at midfrequencies is a very respectable measurement that actually exceeds the specifications.
Fig. 5: Channel separation at 1 watt into 8Ω.
Thus we see that the Parasound A 21, while it doesn’t set world records in any of the various measurement categories, proves to be a thoroughly clean amplifier on the lab bench.
Longtime readers of The Audio Critic know the drill that comes at this point: I repeat, for the nth time, that all amplifiers having high input impedance, low output impedance, flat frequency response, low distortion, and low noise floor sound exactly the same when operated at matched levels and not clipped. (Those who are unable to stomach this simple truth, proved over and over again in double-blind listening tests, should stick with Stereophile.) Of course, the Parasound A 21, with its very high output capability, will not clip at levels where most others do and therefore sounds better at those levels. The deep bass profits especially from all those watts, especially through inefficient loudspeakers. But those who expect the heavens to open up and the seraphim blow their trumpets when they turn on the new amplifier—any amplifier—that they just brought home from the store in their hot little hands will be sorely disappointed.
I know there are some of you out there who just cannot listen to low-priced mass-market audio components (Pioneer, yecch!) no matter how they sound. It goes against your grain and you don’t want to know about it. To you I heartily recommend the Parasound Halo A 21 because it will satisfy your high-end cravings without bankrupting you. You’ll have the high-end cosmetics, the high power, and some cash left in your account. And, yes, it sounds really good, too.
19 February, 2006
Once Again, CD and DVD Reviews
Maybe I should elaborate on, and clarify, my previous comments on the subject of serious (“classical”) music vs. popular music.
Not all classical music is serious, nor is all serious music good. For example, neither Rossini’s William Tell overture nor Johann Strauss’s Blue Danube waltz is serious, but both are classical and both are good. On the other hand, Tchaikovsky’s 1812 Overture is both classical and serious but not very good. Popular music can also be “classical,” in the sense of a “classic,” such as Hoagy Carmichael’s Stardust, for example, which is a popular song that is not a whit inferior to a Schubert Lied. I have the greatest respect for truly good popular music. I think Louis Armstrong, Nat “King” Cole, and Hank Williams were stupendous, just as I think that Aerosmith, Eminem, and Britney Spears are garbage. It is unfortunate that the youngest generation’s exposure to popular music is currently dominated by garbage, but that can change. (All it would take is the emergence of a new really gifted group, such as the Beatles in the ’60s, and its rise to mega-success.) Serious music also went through a wrong-headed, sterile phase in the second half of the twentieth century, and now the tide seems to be turning.
DVD from BBC Opus Arte
“Eroica: The day that changed music forever,” a film featuring Ludwig van Beethoven’s Symphony No. 3 in E-flat Major, Op. 55, with Ian Hart as Beethoven and the Orchestre Révolutionnaire et Romantique, Sir John Eliot Gardiner, conductor. OA 0908 D (2004).
This is not Music Appreciation 101. This is a highly original and thoroughly fascinating movie about the first public performance of the Eroica—not much more than a polished rehearsal—at the palace of Prince Lobkowitz in Vienna in 1804. The prince and his wife, Beethoven, his pupil Ferdinand Ries, and a number of distinguished guests come and go during the performance, sometimes chatting, sometimes listening, Beethoven sometimes conducting and sometimes just sitting or temporarily leaving the room—it’s no big deal, merely the greatest piece of music composed up to that time casually happening in the room. The most poignant moment is the arrival of Haydn between the scherzo and the last movement, who muses that music will never be the same again. It’s all very believable. The cast consists of actors, but the musicians are played by the actual members of Gardiner’s orchestra in period costume. An uninterrupted performance of the entire symphony follows the movie. The playing is absolutely wonderful throughout, much better than I am sure it was in 1804, with an authentic period sound and metrics, most refreshing after all the familiar modern performances. The available audio formats are stereo and DTS 5.1, the latter one of the finest examples of surround sound I’ve heard. I unhesitatingly recommend this DVD to all music lovers.
DVD from Opus Arte
Richard Wagner: Parsifal. Christopher Ventris, Parsifal; Waltraud Meier, Kundry; Matti Salminen, Gurnemanz; Thomas Hampson, Amfortas; Tom Fox, Klingsor. Deutsches Symphonie-Orchester Berlin, Festspielchor Baden-Baden, Kent Nagano, conductor. OA 0915 D (3 DVDs, recorded 2004, issued 2005).
This time the Festspielhaus of Baden-Baden equals or surpasses the Festspielhaus of Bayreuth. I cannot imagine a better-sung present-day production of Parsifal, even in the latter holy of holies. Not that Ventris is a Melchior or Meier a Flagstad or Nagano a Toscanini, but I said present-day. And then there is Matti Salminen, pushing 60 and as good as ever, whose name I can’t trump with an older, historical one; indeed, he is as fine a Gurnemanz as I can imagine, now or long ago or in the future. He almost carries the opera single-handed in his huge role as narrator/factotum. Parsifal is a strange beast; parts of it, such as the Prelude and the Good Friday Spell, represent Wagner at his transcendental greatest, while some passages are deadly bores, as if the old man had run out of ideas in his terminal work. Staunch Wagnerians like me are able to sit through the whole thing with rapt attention, but I don’t expect all music lovers to be as hardcore. Kent Nagano’s conducting is highly focused and controlled; sometimes I wished the orchestra were louder, drowning out the singers, but that’s probably just my bad taste. Nikolaus Lehnhoff’s staging is a bit too bare-bones for my taste; some reviewers liked it but I prefer 19th-century mise-en-scène in Wagner. The DTS 5.1 soundtrack is excellent but not quite as juicy and immediate as in the Beethoven DVD above.
CD from Channel Classics
Gustav Mahler: Symphony No. 6 in A Minor. Budapest Festival Orchestra, Iván Fischer, conductor. CCS SA 22905 (2005).
At this point, every Mahler symphony has so many world-class recordings that another very good one, such as this CD, can’t make much of a dent. Fischer emphasizes the long lyrical line of Mahler’s phrases, making the main themes extremely coherent and memorable. No recording, however, can do justice to Mahler’s orchestration; you have to hear the music live in a good hall. I say that despite the fact that this is an exceptionally fine recording in a state-of-the-art new concert hall. The latter is perhaps the main reason for this review because I am something of a Hungarian chauvinist and the recently built National Concert Hall in the Palace of the Arts in Budapest is a remarkable achievement for a small country. Among other things, the hall’s reverberation time is tunable from 1 second to 4 seconds, an amazingly wide range. It’s truly a 21st-century music venue with sci-fi-like technology. Even so, the CD sounds merely like a wonderful recording, not like the life-size Mahler Sixth I recently heard in Verizon Hall, played by the Philadelphia Orchestra under Eschenbach. In Mahler’s case “the medium is the message”—the live sound of the orchestra is an essential element of the aesthetic content and impact of the music. A recording, no matter how good, is an inadequate substitute, whereas in the case of, say, a Beethoven quartet it’s almost as satisfying as a live performance. Anyway, Fischer’s performance is right up there with the best Mahler Sixths, and both the stereo and multichannel layers of the SACD are flawless. (The multichannel encoding is 5.0.)
CD from Chesky Records
David Chesky: “Area 31.” Concerto for Violin and Orchestra (Tom Chiu, violin); Poem No. 9: The Girl from Guatemala (Wonjung Kim, soprano); Concerto for Flute and Orchestra (Jeffrey Khaner, flute). Area 31 ensemble, Anthony Aibel, conductor. SACD288 (2005).
David Chesky is one of the very few contemporary composers (Jennifer Higdon is another) whose music is comprehensible on first hearing. By comprehensible I mean that a listener who is not a professor of music theory still knows what’s going on. That’s not the same thing as saying that the music is good, but in David Chesky’s case it is. The violin concerto is a highly eclectic, rhythm-driven work, almost a percussion display piece with violin obbligato, rising to a particularly exciting, frenzied climax at the end of the first movement. Jazz and Latin American influences abound—and even Bach, in the third movement, which appears to be a takeoff on Brandenburg No. 3. The violin part is extremely virtuosic and very well played by Tom Chiu, who is actually more of a jazz musician than a classical violinist. The short piece for soprano is a flamenco-flavored setting of a 19th-century Cuban poem, which might as well have been sung in the original Spanish instead of an English translation, since I couldn’t make out the words anyway. The singing is otherwise accomplished and the lightly orchestrated accompaniment quite imaginative. The flute concerto is a lightweight piece in comparison with the violin concerto; it is more impressionistic, with flamenco (lots of handclapping), tango, and bossa nova flavoring. Its main attraction is the absolutely brilliant flute playing of Jeffrey Khaner, principal flutist of the Philadelphia Orchestra. All in all, everything here is immediately enjoyable, hip, well-crafted, beautifully orchestrated modern music. What’s more, the recording by the composer’s own record company is superb, as usual, on both the stereo and multichannel layers. The latter is actually 4.0 (rather than 5.1) encoded, but that suits the music.
CDs from EMI
Olivier Messiaen: Éclairs sur l’Au-delà… Berliner Philharmoniker, Sir Simon Rattle, conductor. 5 57788 2 (2004).
This is the piece some concertgoers walk out on and others stay to worship. I’m somewhere in between. If you expect long, coherent Brahmsian phrases, you’ll be frustrated. If you allow your ears to tune in to the abrupt splashes of gorgeous orchestral color, the bird calls, the shifting rhythms, the sudden pregnant silences, you may end up finding the music beautiful—at least occasionally beautiful. As far as Messiaen’s religious faith and mysticism are concerned, I feel they have more to do with his titles (“Apparition du Christ glorieux,” “Les Sept Anges aux sept trompettes,” “Et Dieu essuira tout larme de leurs yeux…,” etc.) than with the audible content of his music. Even Bach’s great choral works are religious because of the words, not the music; with a secular text the music would be equally plausible. In Éclairs I hear drumbeats, bird calls, string tremolos, etc., not Jesus Christ. I hold with Stravinsky that music doesn’t “express” anything; it isn’t “about” anything but itself. Simon Rattle has stated in an interview that Éclairs, Messiaen’s farewell composition at the end of his long life, is “without a doubt one of the greatest works of the century.” He knows a hell of lot more about music than I do, so I’ll have to accept his dictum but so far I haven’t been deeply moved by this work. The Berlin orchestra plays magnificently, and the stereo recording by Arne Akselberg is very fine, wonderfully detailed, better than what others have done in the Philharmonie. By the way, Éclairs sur l’Au-delà means something like “Glimpses of the Beyond” (nothing to do with chocolate-covered pastry filled with whipped cream).
Franz Schubert: Die schöne Müllerin, D 795. Ian Bostridge, tenor; Mitsuko Uchida, piano. 5 57827 2 (recorded 2003, issued 2005).
Franz Schubert: Winterreise, D 911. Ian Bostridge, tenor; Leif Ove Andsnes, piano. 5 57790 2 (2004).
Few critics would dispute that Schubert was the greatest composer of Lieder (German art songs) of the 19th century. Even fewer would dispute that Die schöne Müllerin and Winterreise are his masterpieces in that genre. Some would dispute, but many would not, that Ian Bostridge is one of the greatest Lieder singers of our time. Bostridge sings these two long song cycles (each a full-length CD) perhaps more idiosyncratically than the great German singers of the grand tradition, sometimes emphasizing the words more than the musical line, but he certainly communicates the dramatic essence of each song. Being a tenor, he sings all songs in their original key, not transposed, for maximum authenticity. His German diction is superb, which is more than one can say about most English and American singers. As for the wonderfully imaginative piano accompaniments, Mitsuko Uchida and Leif Ove Andsnes are both great artists and play the piano parts with the utmost sensitivity. The recordings are in two different venues but by the same producer/engineer team; in both instances the voice/piano balance and the acoustic perspective are just right. Dozens and dozens of great interpreters have recorded these works, but these two CDs are definitely competitive.
Richard Wagner: Tristan und Isolde. Placido Domingo, Tristan; Nina Stemme, Isolde; Mihoko Fujimura, Brangäne; René Pape, König Marke; Olaf Bär, Kurwenal. Orchestra of the Royal Opera House, Covent Garden; the Royal Opera Chorus, Covent Garden; Antonio Pappano, conductor. 5 58006 2 (3 CDs & 1 DVD, 2005).
There has never been a more influential work in the history of music than Tristan und Isolde. For a hundred years, or more, after its premiere in 1865 composers have imitated its unrelieved chromaticism, a musical idiom that was totally new with Wagner, and even movie music is nothing but bowdlerized Tristan when it tries to be romantic or climactic. Wagner’s switch, in the middle of composing the Ring, to total chromaticism, followed by the reverse switch to the apotheosis of the diatonic scale in Meistersinger, is the most astonishing example of stylistic versatility in classical music. What is also remarkable is that he never went back to the Tristan idiom after resuming work on the Ring. This new recording has been referred to as “Domingo’s Tristan,” as if the 65-year old (just under 64 at the time of recording) superstar’s durability were the main feature. Actually, Domingo never sang the role in any opera house; the recording is a careful editing job made over a period of a month and a half. (It is probably the last million-dollar recording project by any classical label under the current depressed conditions.) Domingo is a wonderful musician, and his unfailingly intelligent, lyrical, expressive singing can still sound beautiful at middle volume. In the ranting and raving passages of Act 3, however, the strain begins to show, and not just a little. He is not a true Heldentenor; at full volume there remain no reserves of strength. That he is still a very plausible Tristan at his age is in itself a phenomenon. The young Swedish soprano Nina Stemme is exactly the opposite case; her voice is absolutely solid and unstrained from top to bottom and she can belt it out at triple fortissimo, but in the Liebestod the lack of a chesty bottom foundation makes her voice less than thrilling (in the Flagstad or Traubel or Nilsson sense). The greatest voice in the cast is actually that of René Pape; when he launches into King Marke’s second-act monologue one has the feeling that we are finally in a bigtime opera house. The orchestral playing by the Covent Garden band is first-rate, no reservations, and Pappano’s conducting is very alert, although the great preludes to Act 1 and Act 3 could both go a little faster. The stereo recording is exceptionally fine, very transparent with excellent structural detail; the DTS 5.1 soundtrack of the DVD is strictly routine, probably an afterthought, with sonically congealed climaxes. The video is the full text of the libretto on the screen. Overall I would grade this effort as a high B+, maybe even an A–. It is not quite on the level of the 1952 mono recording in the EMI catalog, with Furtwängler, Suthaus, and Flagstad.
CD from Harmonia Mundi
Anton Bruckner: Symphony No. 7 in E Major. Orchestre des Champs-Elysées, Philippe Herreweghe, conductor. HMC 901857 (2004).
I don’t pretend to be a highly qualified Brucknerian, but to my ears this is a revelatory performance. Herreweghe is famous for his period-practice Bach, but period-practice Bruckner with 19th-century winds and gut strings is equally illuminating. Instead of the somewhat constipated grandiosity of the standard renditions, what emerges here is a totally transparent, structurally coherent, sometimes lyrical, sometimes heroic, balanced composition, perhaps smaller in scale than one is used to but much more convincing and appealing—Bruckner renascent! Herreweghe’s rather brisk tempi are part of the reason—how some of the usual performances drag!—but the main ingredient is the textural clarity. The climaxes are still as powerful as can be, no problemo. This may not be everybody’s cup of Brucknerian tea but I am sold. The stereo recording is gorgeous, as transparent in structure and texture as the performance itself.
CD from Sony Classical
Antonín Dvorák: Concerto for Cello & Orchestra in B Minor, Op. 104 (“The Secrets of Dvorák’s Cello Concerto”); “Lasst mich allein,” Op. 82, No. 1; Zigeunerlieder, Op. 55. Stephen Foster: “Jeanie with the Light Brown Hair” & “Wilt Thou Be Gone, Love?” Jan Vogler, cello; New York Philharmonic, David Robertson, conductor; Angelika Kirchschlager, mezzo-soprano; Helmut Deutsch, piano. 82876737162 (2004–2005).
The “editorial” theme of this release seems to be musicologist Michael Beckerman’s theory of a link between Dvorák’s cello concerto and his song “Lasst mich allein,” as well as Stephen Foster’s influence on the concerto, the emotional connection to the life and death of Dvorák’s sister-in-law Josefina Kounicova, and so forth. I don’t particularly care about any of that stuff; what I care about is the jolt I got from this CD when I first played it. This is the best recording of the Dvorák cello concerto I have ever heard! I may be influenced by the irresistibly gorgeous music that each time makes the last performance one has heard seem the best, but I don’t think so. Both Jan Vogler and David Robertson are up-and-coming artists of some prominence, but I wouldn’t have expected them to leave the competition in the dust—which is what they do (in my opinion). Robertson inspires the splendid New York Philharmonic to play this warhorse like a world premiere, setting a fairly brisk pace that sweeps the music relentlessly and unfussily along, and Vogler plays like an angel, with passion, great musicality, and wonderful tone. I think the few critics who have already reviewed this performance, all of them more or less favorably, were much too cautious. I was moved to tears. The stereo recording by a German team in New York’s dreadful Avery Fisher Hall is thoroughly transparent and structurally detailed, as if the acoustical difficulties did not exist. After the concerto, Angelika Kirchschlager’s beautiful singing of the songs (to prove Beckerman’s theories) is mere icing on the cake.
CDs from Water Lily Acoustics
Gustav Mahler: Symphony No. 5 in C-sharp Minor. Saint Petersburg Philharmonic Orchestra, Yuri Temirkanov, conductor. WLA-WS-76-SACD (recorded 2003, issued 2005).
Dmitri Shostakovich: Symphony No. 7 in C Major, Op. 60 (“Leningrad”). Saint Petersburg Academic Symphony Orchestra, Alexander Dmitriev, conductor. WLA-WS-77-SACD (recorded 2003, issued 2005).
Yevgeny Svetlanov: Piano Concerto in C Minor.* Alexander Skryabin: Symphony No. 3 (“The Divine Poem”). *Vladimir Ovchinnikov, piano; Saint Petersburg Academic Symphony Orchestra, Alexander Dmitriev, conductor. WLA-WS-75-SACD (recorded 2003, issued 2005).
Recording engineer Kavichandran Alexander (“Kavi”) is a rock-ribbed purist. I know him, I respect him, and I understand him. He believes in the purity, and therefore the supremacy, of the classic Blumlein microphone array for all recording purposes. Nothing can shake his faith. If a Blumlein recording is great, it’s only natural. If it isn’t, it’s still not Kavi’s fault because the superiority of the Blumlein technique remains indisputable. Contrast this with the philosophy of the great (and recently retired) John Eargle, who always said that a recordist must be free of preconceived technical notions and totally opportunistic, using all kinds of microphones, in small and large numbers, in all kinds of configurations and deployments depending on the venue, as long as the resulting sound is superior. These live DSD recordings in the Great Hall of the Saint Petersburg Philharmonia, which Kavi had been dreaming for long years to make, illustrate the point—Blumlein purism has its pluses and minuses.
To restrict ourselves for the moment to the basic stereo CD layers, the sound is 100% honest—no gimmicks, no highlighting, no compression, no EQ, no processing of any kind. There is a very good sense of the size of the hall (at least through my Linkwitz Lab “Orion” speakers); directional cues are very accurate; front-to-back information is clear; and the dynamic range is huge. The latter is actually a problem; since full-scale 0 dB is reached only occasionally, at the very loudest moments, setting your listening volume to tolerability on those few passages makes most of the music too low in level. Some judicious raising of the dynamic floor and lowering of the ceiling, as practiced in the best big-label recordings, actually results in a more listenable product, unless the compression is excessive. And that’s not even the biggest problem. To quote John Eargle’s The Microphone Book (2nd edition, Focal Press, 2004) on the subject of Blumlein performance, “a wide array of performers may require the microphone pair to be placed too far from the performers for the desired degree of presence.” That’s the main weakness of these otherwise splendid recordings. Everything is a bit too much over there, rather than here. The Svetlanov/Skryabin disc is actually better in this regard than the other two; it was recorded with a modified Blumlein pair (parallel figure-8 configuration) as against the classic Blumlein array (crossed figure-8s) used in the Mahler and Shostakovich.
As for the SACD layers, they are completely artificial in the Mahler and Shostakovich. Only two channels existed on the master; they were converted to 5.0 channels through a mathematical algorithm (the third disc remained 2-channel). I found the resulting sound to be less open and less finely detailed, as well as narrower in lateral spread, than the original stereo versions. Furthermore, the SACD layers had frequent dropouts on my copies—I hope only on mine. I wish these recordings had remained pure stereo releases.
When it comes to the musical performances, I focused almost exclusively on the Mahler, since I find the Shostakovich Seventh to be insufferably banal and tedious, the weakest by far of his 15 symphonies, and the other Russian compositions are new to me. (Toscanini conducted the “Leningrad” symphony during World War II out of political solidarity with the Russian allies, and when his son played for him a recording of it 15 years later, he asked, “Did I play that?” and being told “Yes,” he remarked, “I must have been crazy.”) The Saint Petersburg Philharmonic isn’t your ideal Mahler orchestra; the strings are rather lusterless (I think they use little or no vibrato) and the brasses are far from golden. The opening trumpet solo of the Mahler Fifth is played with very poor tone; I have heard better trumpet playing from a high-school band, although it improves later on. I don’t think the orchestra is as good today as it was under Mravinsky, whose era ended in 1982. (Check out the 1960 Mravinsky recording, made in London for the Deutsche Grammophon label, of the last three Tchaikovsky symphonies—sensational!) Temirkanov conducts the Mahler in a somewhat flabby and boring fashion; it is still a well-shaped performance overall but not really competitive with all the great recordings over the years, from Bruno Walter (1947) to Simon Rattle (2002). The main importance of this disc—of all three discs, for that matter—is the documentation of a recording technique which has almost vanished from the scene but whose virtues should not be forgotten.
13 February, 2006
The Realities of Audio: an Old Man's Musings
Three months from now I’ll have my 80th birthday. I’ve been writing on the subject of audio for 50 years, 30 of them for The Audio Critic, and at this point I am something of a burnout. Specifically, I’ve lost all patience for the wide-eyed wonderment of reviewers over the latest and greatest audio gear.
The realities of audio are exceedingly simple, not at all complex or mysterious. Audio is an old technology. Not much has happened over the last 50 years. For example, the stereo recordings of the Chicago Symphony Orchestra under Fritz Reiner that Lewis Layton made for RCA Victor 50 years ago are every bit as good as anything recorded today, so how much progress could there have been? Even the transition from analog to digital technology was basically a forward step in method, not necessarily in results.
My burnout condition results in total boredom when I hear about a new seven-channel receiver or a new loudspeaker with forward-firing drivers in a rectangular box. It takes something a little bit different to get me even mildly excited. Loudspeakers like the B&O BeoLab 5 or the Linkwitz Lab “Orion” can still jolt me out of my ennui. So can a $180 high-powered amplifier like the Behringer A500. Products like that are rare, however. Most have no distinguishing attributes, no matter how hard the admen try. I see little or no reason to review me-too products, although every once in a while I do.
Allow the old burnout to make some curmudgeonly generalizations here that may turn out to be more enlightening, especially to new readers, than any specific review. To wit:
No piece of electronic gear, no matter how “cool,” will change your audio life. Whether it’s the latest digital circuitry or the most retro vacuum-tube design, the sound will remain just about the same—you will not discover unsuspected new beauty. More convenience, greater efficiency, better ergonomics, slicker functionality—maybe (especially with up-to-date digital technology), but no greater beauty of sound. For that you need a new loudspeaker. Not one with forward-firing dynamic drivers and a passive crossover in a closed rectangular box, no matter how costly. That vein has been mined and is now exhausted. Look for active (powered) speakers, maybe open-backed, maybe with special dispersion devices, maybe electrostatic, maybe line sources, maybe DSP-corrected—there are a number of possibilities. I can’t promise they will all be good but I can tell you that you won’t find astonishing new sounds coming out of “monkey coffins” (i.e., rectangular boxes with conventional drivers).
Think about it. Doesn’t it stand to reason that the last link in the audio chain, the thing that actually produces the sound waves, is the limiting factor of sound quality? The trouble is that the new loudspeaker capable of changing your audio life is likely to be large and difficult to fit into your home décor. Your better half may say, “Over my dead body!” So, instead, you’ll lug a shiny new amplifier home in your hot little hand and swear that the sound is infinitely better. Poor deluded soul…
As I said, the realities of audio are simple. Only some audio journalists make them complicated.
peteraczel | 10 December, 2005 20:18
8-Channel Power Amplifier
Bryston Ltd., 677 Neal Drive, P.O. Box 2170, Peterborough, Ontario, Canada K9J 7Y4. Voice: (705) 743-5325. Fax: (705) 742-0882. E-mail: firstname.lastname@example.org. Web: www.bryston.ca. 875HT eight-channel power amplifier, $5195.00. Tested sample on loan from manufacturer.
Reviewing a Bryston product is usually a simple and straightforward matter because it’s most unlikely that there is anything wrong with it. The only thing wrong in this case is the price—the 875HT is a wonderful amplifier but not very good value at $5195. There are, for example, 12-channel power amps by B&K, ATI, and others in the $1500 to $2000 range that may not quite equal the Bryston in specs but aren’t functionally inferior and have four more channels. I have the greatest admiration for Bryston engineering, but this product isn’t competitively positioned in the market. The serial number of my sample was 000012, and the 875HT is not a very new model. Doesn’t that tell you something?
One of my main reasons for wanting a review sample of the 875HT was to try it out on my Linkwitz Lab “Orion” speaker system, which can use four amplifier channels per side for the four drivers (see the February 2005 review on this website). The Bryston drove the Orions flawlessly, but was it any better than my old 6-channnel McIntosh MC7106, with the two woofers per side paralleled? I heard very subtle differences, probably due to the different woofer hookups; unfortunately my ABX double-blind comparator cannot switch between two multichannel amplifiers, so an objective sonic determination could not be made. Basically, it was six of one and half a dozen (well, eight actually) of the other.
Of course, a much more common application of the 875HT would be to drive all the speakers in a surround system. The amplifier could accommodate even a 7.1 system with an unpowered subwoofer, using one channel on each speaker. A 5.1 system with a self-powered subwoofer could use bridged channels on each of the left, center, and right speakers, and single channels on the surround speakers. Alternately, the amplifier could power four separate stereo systems in four different rooms. The permutations and combinations are almost endless.
The layout of the 875HT is simplicity itself. The eight identical power-amp modules run parallel from front to back. The abutting heat sinks form a ventilating grid on top. The back panel has eight unbalanced RCA jacks, eight balanced XLR jacks (without push tabs), eight speaker terminals (accepting dual banana plugs/spade lugs/bare wires), and switches for bridging adjacent channels to form four mono amplifiers. The front panel has nothing but an on/off switch plus eight LEDs to indicate power in each channel. No other bells and whistles.
[Dr. David Rich, our erstwhile technical editor and favorite EE authority, is supposed to contribute a circuit analysis/critique to this review. I shall append it when I get it; meanwhile I want to post the body of the review forthwith.]
The small-signal frequency response of the Bryston 875HT I shown in Fig. 1. The deviation from total flatness is only –0.025 dB at 10 Hz and –0.08 dB at 20 kHz, but the gradual rise to a maximum of 0.045 dB at 9 kHz is somewhat unusual (although inaudible, of course).
Fig. 1: Frequency response of one channel at 1 watt into 8Ω.By far the most important power-amplifier measurement is distortion vs. power output. Fig. 2 and Fig. 3 show the THD+N of one channel of the 875HT into 8Ω and 4Ω loads, respectively, with inputs of 20 Hz, 1 kHz, and 20 kHz. The three curves tend to coincide in the best amplifiers, including Bryston’s stereo models, so the significant separation seen here is a little bit strange. The measurement bandwidth was extended to 80 kHz for the 20 kHz distortion curves, to include the 2nd, 3rd, and 4th harmonics; therefore, obviously, more noise was included. The 20 Hz curves, on the other hand, are normally expected to lie right on top of the 1 kHz curves. Even so, the measurements meet and exceed Bryston’s specs as printed in the owner’s manual and as certified on the individual checkout sheet that comes with each unit—except at 20 kHz, where the shortfall is minimal. This is still a very low-distortion amplifier.
Fig. 2: THD+N vs. power of one channel into 8Ω at 20 Hz (green), 1 kHz (blue), and 20 kHz (red).
Fig. 3: THD+N vs. power of one channel into 4Ω at 20 Hz (green), 1 kHz (blue), and 20 kHz (red).The FFT spectrum of a 1 kHz tone at clipping level into 8Ω, shown in Fig. 4, indicates that the THD is dominated by the 3rd harmonic, all other harmonics being of significantly smaller amplitude. Even the 3rd harmonic, however, is at an extremely low level.
Fig. 4: Spectrum of a 1 kHz tone at approx. 90 watts into 8Ω.
The single-point noise of the amplifier, with a measurement bandwidth of 22 Hz to 22 kHz and referenced to clipping level into 8Ω, was –107.7 dB. That’s an excellent figure and it accords well with Bryston’s specs.
Fig. 5 shows the crosstalk (i.e., separation) between two adjacent channels at a level of 1 watt into 8Ω. Adjacent channels are more susceptible to crosstalk than widely separated channels, and the measurement here indicates flawless performance. (Bryston appears to provide no crosstalk specs.)
Fig. 5: Channel separation (adjacent channels) at 1 watt into 8Ω.
One of the most revealing amplifier measurements is the PowerCube test. This test, more commonly seen in Europe, measures the ability of an amplifier to drive widely fluctuating load impedances, such as presented by certain loudspeakers. As far as I know, The Audio Critic is the only American audio journal to publish PowerCube measurements. The instrument for the test is made in Sweden; it produces repeated 1 kHz tone bursts of 20 ms duration into 20 different complex load impedances across the amplifier (magnitudes of 8Ω, 4Ω, 2Ω, and 1Ω, phase angles of –60°, –30°, 0°, +30°, and +60°), registering maximum output at 1% distortion. The graphic output of the instrument shows the 20 data point connected to form a more or less cubelike polyhedron. The test really separates the men from the boys when it comes to real-world loads rather than just resistances.
The PowerCube of one channel of the Bryston 875HT is shown in Fig. 6. Interestingly enough, it is not even as good as that of the dirt-cheap Behringer A500 (see the December 2005 review on this website). The power supply cuts out at 31.6 volts into 8Ω (125 watts), which at least it is able to deliver into all phase angles at 1% distortion, and then fades out significantly at lower impedances. I expected a more gentle slope of the top of the polyhedron, i.e., more power into the lower impedances, especially 4Ω. The power supply of each channel appears to be rather limited.
Fig. 6: PowerCube of one channel with two channels driven. The three axes are output in volts, impedance in ohms, and phase angle in degrees.
An amplifier with the measurements of the Bryston 875HT has no sound of its own. To talk about the soundstaging, midrange immediacy, etc., of such an amplifier is audio-cultist nonsense. The sound of the 875HT’s output is the sound of its input.
The 875HT is a classic Bryston power amplifier with slightly compromised power supplies for its eight channels in comparison with Bryston’s stereo (two-channel) models. Even so, it can be trusted to perform flawlessly in any kind of multichannel installation. The only problem is the inflated price.
The Bryston 875HT: Topology and Afterthoughts
By David A. Rich, Ph.D. Engineering Consultant
Editor’s Note: Like so many other distinguished members of the engineering community, David Rich has a cavalier attitude toward English syntax, punctuation, and spelling. I spent only a limited amount of time editing his stream-of-consciousness writing and therefore cannot guarantee flawless copy.
Bryston is the only company I know of that puts its schematics on the Web so you can see the full schematic of each unit. Since it has been a long time since I looked at a Bryston, let’s have a brief review of what’s inside all their offerings.
Bryston amps are fully discrete, including the balanced-to-single-ended converter (one per channel) that precedes the main power amplifier. In bridged mode they use one of the discrete amplifiers for the balanced-to-single-ended conversion and the other for the phase inversion needed to create the bridged outputs. Please do not confuse a bridged amplifier with a fully balanced amplifier, which has many advantages over a bridged amp. The only fully balanced amplifiers known to me are the products of Spread Spectrum Technologies (James Bongiorno’s company).
Each Bryston amp is unique in that the stages that provide current gain also supply voltage gain. The voltage gain is to 4.75, set by a nested feedback loop. The closed-loop voltage gain is possible because transistor stages inside the feedback loop are not emitter followers. Recall that the emitter followers used in the back end of a standard amplifier supply no voltage gain.
What is the topology Bryston uses to provide voltage gain? In the first stage, it is a common emitter amplifier. This drives a composite Darlington, with the collectors of the Darlington tied to the amplifier’s output. For those of you into such things, the nested feedback loop is taken at the speaker output and returned to the emitter of the common-emitter amplifier. In other words, current feedback.
In larger Bryston amplifiers, an additional very novel compound transistor circuit follows the Darlington, but that stage is missing in the 875HT. Putting voltage gain in the output stage allows the preceding stages, which provide the bulk of the open-loop voltage gain of the amplifier, to be run from regulated power supplies. The regulated rails are at a lower voltage than the unregulated power rails connected to the output stages (they need to swing only 25% of the output voltage). In a normal amplifier, with the output current-gain stage having a gain of only 1, the preceding stages would have to be run off the power supply that supplies the output rails, lest the amplifier clip at a lower voltage set by the clipping point of the voltage-gain stages.
Gain in the output stage and the nested feedback loop reduce distortion in two ways:
(1) the nested feedback loop, which has a wider bandwidth than the complete feedback loop;
(2) the voltage-gain stages ahead of the nested feedback loop only need to swing at 20% of the output voltage swing. Since distortion is the result of nonlinearity, the less an amplifier signal moves the less distortion occurs.
So why doesn’t everybody do this? I believe the primary reason is that the Bryston topology could oscillate into some loads and when clipped, unless the engineering talent behind the amplifier really understood all the third-order issues that could bring about the oscillations. I am convinced the Bryston engineers have that understanding.
The Bryston voltage amplifier stages are less complex than those of other amplifiers we have looked at that produce very low distortion at 20 kHz. First, no circuit to linearize the second voltage-gain stage is included in the Bryston. Douglas Self has written extensively on distortion mechanisms in traditional power amplifier designs. (2002. Audio Power Amplifier Design Handbook. 3rd ed. Newnes.) He identifies the need for an emitter follower before the second gain stage, or the use of a cascode transistor as part of the second gain stage, as key circuit elements to reduce distortion.Second, the differential pairs are biased by resistors, not an active current source. This can result in a reduced power-supply rejection ratio, but this is less of a problem with the regulated supply rails of the Bryston. We have a remaining problem, however, that is more subtle—the common-mode signal at the differential-pair input is suppressed less than if the current source were in place. A reduced common-mode rejection ratio of the differential pair can lead to distortion. Are these two circuit simplifications the source of distortion we see in the Audio Precision curves? Probably not, since the same circuits are used in the Brystons with higher power, which yielded some of the lowest numbers we have seen. The regulated rails and reduced signal swings that are unique to the Bryston appear to overcome the downside of the simplified front-end circuits. So why does this amplifier have more distortion than a typical Bryston amplifier? (They specify this amp will distort by a factor of two over the more powerful Bryston models.) The answer is most probably that the number of amplifier stages inside the nested feedback loop is reduced by one, and the stage eliminated is an interesting topology proprietary to Bryston. I also note that the amplifier’s noise is not state of the art. Noise dominantly comes from the differential stage. Spread Spectrum Technologies again appears to be in the lead here.
The output stage uses a foldback current limiter. This can cause trouble with early activation of this limiter into an inductive or capacitive load. The PowerCube shows this amp does not have that problem. Modern amplifiers for home applications use IV sensor circuitry which is independent of the amplifier itself. Complicated versions of these circuits can almost calculate if the output transistors are in their safe operating region. If you refer to the spec sheet of a power transistor, you may see multiple Safe Operating Area (SOA) curves. One will be for dc operation and the remaining ones, which allow more power to be dissipated, are only for short periods of operation. Complex external protection may allow the amp to deliver more current for a short sine-wave burst (what the PowerCube generator drives into the amp) before the amp is shut down for exceeding the dc SOA. Some amplifier manufactures are taking advantage of this and are bring back the dynamic power spec, although current FCC regulations were designed to prevent this sort of thing.
The problem with external current- and voltage-limit protection is that when the protection is activated, relays in series with the speaker terminals open (the Bryston approach does not need the relays, which could cause a slight decrease in amplifier reliability) and the amp shuts down. You have to power-cycle it or press a reset button to bring it back to life. Fine for home use but unacceptable for a rock concert. The amplifier also includes clipping indicators, again as a warning to the pros that the amp could be getting ready to cut out because of the IV current limiter or, worse, come to a thermal shutdown (cycle time on this fault would be longer).
The unit has two power transformers (one for four channels). Each transformer has two 33,000 μF primary filter capacitors. In low-priced AV receivers rated at similar power output, we see much less primary capacitance. This is one reason we do not see FCC power ratings for all six or seven channels driven on these receivers, the other reasons being the transformer’s ability to supply current and the size of the heat sinks to dissipate the energy lost in the class B amplifiers. On the other hand, Bryston does not specify an FCC rating for this amplifier driven into 4 ohms. It does so for its other products.
Also, I note that Bryston specifies a maximum current rating for the ac line coming into the unit at 14 amps, which is just under the rating for a standard wall outlet (leaving 1 amp to supply everything else on the same ac loop that may serve several rooms in your house). This is an indication that the amplifier can drive significant current to the speaker load. Look at the back of some other 7-channel amplifiers and see what they give as a maximum current spec. A final point on the same subject is that UL would not approve an amplifier that can draw much more current. 125 watts into 4 ohms times 8 channels is about it. Amplifier manufacturers selling 300-watt channels times 7 will not pass UL, and you can see the absence of the label on these amplifiers. In reality, you would need to hang a 30-amp 220-volt fuse on these amplifiers to prevent them from popping a fuse. These giant amplifiers do not do this in real life because they never go near full power, at least not simultaneously on all channels. Why has no multichannel power amp been offered with the correct power cable—you guessed it, the high-end dealers would go crazy with thoughts of reduced sales. Imagine them having to say, first call your electrician and then come back. These same high-end dealers will of course happily sell you power conditioners that do nothing for well-designed amplifiers. The Bryston is especially well-designed with respect to the ability to reject power-supply noise, since the voltage-gain stages are regulated. (No, tweaks, the last thing you want to do is regulate the output stage, which would only limit the voltage that the amplifier can swing under dynamic conditions.)
Finally, I do want to point out that honest AV installers (the ones without the store front and no need to sell useless junk at 50 points profit) may well bring a separate ac line into your home-theater rooms. That’s not a tweako move but a recognition that all the fancy lighting and electronics (including multiple subwoofers) may indeed need to be fed by multiple supplies. Tip-off to a rip-off—any AV installer who tries to load up your installation with high-end wire, power conditioners, or high-end amps should be shown the door. The majority will not do so but they still have to make a living. What you should see instead on the final bill is a specific charge for theater design, which may be billable at four-figure rates by an acoustician with an advanced degree and a significant portfolio. Designing a good home theater is hard and expensive. Designing a poor one loaded up with power conditioners, etc., is easy and expensive.
Should the Bryston 875HT be part of your home theater? I really do not think so. It is overpriced for home applications. Instead consider multiple Bryston 4B SST’s (full Bryston topology with an FCC rating of 500 watts per channel into 4 ohms and a much lower price per watt), driven by multiple 15-amp lines. This is certainly overkill in the way a BMW 7 Series is, but it is not like paying the same price for a Pinto with a special carburetor that is claimed never to need fuel. Those who want a Ferrari should look up the Spread Spectrum Technologies Ampzilla 2000. At $2750 per channel ($19,250 for seven!) it is double the price per watt of the Bryston, and like the Ferrari may not be altogether reliable, for example for use in sound reinforcement applications. Those who don’t have cash dripping from their pockets are directed to 7-channel amps with UL labels and FCC power ratings into 7 channels at 4 ohms. The maximum power will be no more than 150 watts into 4 ohms, all channels driven, if UL is on the back. This should cost you about $1500 to $2000.
02 December, 2005
2-Channel Power Amplifier
Behringer A500 “Reference Amplifier”
When I opened up the box the A500 came in and saw it for the first time, I said to myself, “This is either the most incredible bargain in the history of audio or a total fraud!” The MSRP is $230; I’ve seen it listed on the Internet for $180; and it’s a pretty nice-looking stereo amplifier rated at 160/160 watts into 8Ω, with quite a few professional features. Come on, what’s going on here?
Well, there are a number of things going on. To begin with, the measured performance of the A500 isn’t up to the level of a Bryston or a McIntosh, although that doesn’t mean the A500 will sound worse. (As I have said, and written, innumerable times, any two amplifiers with high input impedance, low output impedance, flat frequency response, and sufficiently low distortion and noise will sound exactly the same at matched levels if not clipped.) Then there are construction details, such as the XLR input jacks without push tabs, the bare-wires-only output terminals, the flimsy front panel, etc., etc., that would obviously be better on costlier amplifiers. The fact remains, however, that Behringer is able to offer sophisticated audio equipment at lower prices than anyone else. It’s a lesson to all of us audiophiles.
Behringer is a 16-year old German company with an exceptionally rapid worldwide growth pattern in the field of professional audio. At this point they cover the globe with a full line of products for musicians and sound engineers. These include mixing consoles, analog and digital signal processors, guitar amplifiers, studio reference monitors, microphones, public address enclosures, etc. The lesson Behringer exemplifies is that large-scale production combined with professional engineering can result in very high-quality products of great complexity at an amazingly low price. Think computers. How much would a top-of-the-line Dell or Gateway cost if manufactured in the quantities of a Mark Levinson or Krell preamp? Probably half a million. Professional audio on the Behringer scale marches to a totally different drummer than high-end consumer audio. Products are engineered for functionality, not for image and talking points, and made in sufficient quantities to eliminate manufacturing inefficiencies. As a result, features and performance can often equal and sometimes even surpass the high-end consumer product. It’s something that wide-eyed audiophiles should be more aware of.
The A500 is advertised as a “professional reference-class studio power amplifier” and at least in some ways it lives up to that highfalutin appellation. Each of the two channels has three input modes instead of one: balanced XLR, balanced ¼" phone jack, and unbalanced RCA. Each channel has a click-stop volume control and a multi-LED level meter that also indicates clipping. There is a fairly substantial toroidal power transformer, and the heat sinks are also far from puny. All that for $180 (all right, for $230). On the other hand, the so-called professional output terminals accept only spade lugs or bare wires—no banana plugs. And when I used the XLR jacks, one of them felt pretty loose—but it worked. (If a Mark Levinson or a Krell had loose input jacks, I’d send it back.) In addition, there are output jacks for speakers equipped with ¼" mono phone plugs, as found in some studios. What’s more, the two channels are bridgeable for mono operation with doubled power.
I had no circuit schematics, but the amplifier is claimed to be “servo-controlled.” Is that Behringerese for a feedback loop? Probably. But I really shouldn’t be so flip. For the money, the A500 is a minor miracle. If it turned out to be reliable—only time will tell—it would be a major miracle.
The specifications of the A500 are a bit too sanguine, it seems, but maybe it’s just my sample. With a little more conservative speccing the numbers could be right-on and still nothing to be ashamed of. What’s wrong with a 120/120-watt amplifier?
I’ll depart from my usual sequence of tests and start with the PowerCube because it gives a quicker overview of the amplifier’s performance. The PowerCube test measures the ability of an amplifier to drive widely fluctuating load impedances, such as presented by certain loudspeakers. As far as I know, The Audio Critic is the only American audio journal to publish PowerCube measurements. The instrument for the test is made in Sweden; it produces repeated 1 kHz tone bursts of 20 ms duration into 20 different complex load impedances across the amplifier (magnitudes of 8Ω, 4Ω, 2Ω, and 1Ω, phase angles of –60°, –30°, 0°, +30°, and +60°). The graphic output of the instrument shows the 20 data point connected to form a more or less cubelike polyhedron. The test really separates the men from the boys when it comes to real-world loads rather than just resistances.
The PowerCube of the A500 is shown in Fig. 1. There is basically nothing wrong with it. The sloping characteristic of the top of the polyhedron merely shows that the power supply is limited. Into an 8Ω load with a 0° phase angle (purely resistive) the maximum output is a little over 33 volts at the test limit of 1% distortion, which translates to 138 watts. Into 4Ω/0° the maximum output is a hair under 30 volts, equivalent to 220 watts, and then successively less into 2Ω and 1Ω. The output holds up extremely well, however, into capacitive (–) and inductive (+) phase angles at each impedance, which is most unusual in an inexpensive amplifier. A more nearly cubical picture could be drawn only by an amplifier with a much heavier power supply.
Fig. 1: PowerCube of one channel with both channels driven. The three axes are output in volts, impedance in ohms, and phase angle in degrees.Fig. 2 shows the small-signal frequency response of the A500. The low-frequency response is unexceptionable, but on the top end –0.2 dB at 10 kHz and –0.6 dB at 20 kHz is a bit too much of a rolloff in my opinion. An 18-year-old audiophile could conceivably hear an infinitesimal dulling of transients through the amplifier. Not very likely, but not out of the question.
Fig. 2: Frequency response of one channel at 1 watt into 8Ω. The other channel was identical.The “king of curves” in power-amplifier testing is distortion vs. power output. Fig. 3 and Fig. 4 show the THD+N of the A500 into 8Ω and 4Ω, respectively, at 20 Hz, 1 kHz, and 20 kHz. The curves are clearly noise-dominated and pretty much the same regardless of frequency, except that the 20 kHz curve shows a lot more noise at lower levels because its measurement bandwidth was opened up to 80 kHz to include the 40, 60, and 80 kHz harmonics.
Fig. 3: THD+N vs. power of one channel into 8Ω at 20 Hz (green), 1 kHz (cyan), and 20 kHz (red). The other channel was equal or better.
Fig. 4: THD+N vs. power of one channel into 4Ω at 20 Hz (green), 1 kHz (cyan), and 20 kHz (red). The other channel was equal or better.
Two things are obvious from these measurements. The minimum distortion never goes below –72 dB (0.025%), even in the best case, and the clipping levels are approximately 120 watts and 180 watts (generously!) at 8Ω and 4Ω. Not that there is anything wrong these numbers; they indicate a completely transparent amplifier of considerable power—but Behringer’s specs are <0.01% distortion and 160/230 watts into 8Ω/4Ω. As I said, maybe it’s just my sample, or maybe the manual was printed before actual production units came off the line, or maybe Behringer’s measurement conditions are based on a totally different standard. (I use the Audio Precision SYS-2722 instrument, the de facto standard in the USA.)
Fig. 5 shows the FFT spectrum of a 1 kHz tone at clipping level into 8Ω, in the same channel as Fig. 3. The Fig. 3 numbers are confirmed, but the good news is that the distortion is almost completely dominated by the second harmonic, which is basically harmless. (Thank heaven for FFT.)
Fig. 5: Spectrum of a 1 kHz tone at approx. 120 watts into 8Ω.
I also measured the single-point noise of the A500 (which needs no graphic representation). With a measurement bandwidth of 22 Hz to 22 kHz, it came to –99 dB in one channel and –100.5 dB in the other. That’s a higher noise floor than found in the best amplifiers but low enough for high-quality playback—you won’t hear it.
Channel separation (or crosstalk) is shown in Fig. 6. In most amplifiers crosstalk decreases steadily as the frequency is lowered; here it remains at a constant level which is a bit higher than ideal but still inaudible. The 4 dB difference between left-into-right and right-into-left crosstalk is normal variation and nothing to worry about.
Fig. 6: Channel separation at 1 watt into 8Ω.
The measurements of the Behringer A500 are not quite as good as those of any number of more expensive solid-state amplifiers but they are more than good enough to meet all the criteria for transparent sound as specified above, in the second paragraph of this review. There is no such thing as an effect without a cause, and there is no scientifically verifiable characteristic that would cause the A500 to sound different from any other amplifier that meets those criteria. The main reason why golden-eared audiophiles hear differences between amplifiers that do meet those criteria is that they don’t listen at matched levels. (Let’s not even bring up the more complicated subject of double-blind listening tests.) If one amplifier is just 0.2 dB louder than another, it will sound different, and therefore “better” or “worse.”
Someone is sure to say at this point, “Well, what about that –0.6 dB rolloff at 20 kHz?” Come on. I can’t hear it; millions of others can’t hear it; if you can hear it, let that be the one and only way the A500 sounds “different.”
No, sound quality is not the issue here. I am not going to give you quasi-pornographic descriptions of the bloom of the high strings on one CD and the plumpness of the lower midrange on another, as I listened to the A500. Reliability is the one unanswered question in this case. When a high-performance piece of gear is this cheap, you naturally wonder how it will hold up under use. The A500 is too new to have a track record.
The Behringer A500 is an amazing phenomenon at the price. There is nothing else like it. I’ll tell you what. If you need a new power amplifier, or maybe just a spare amplifier, throw caution to the wind. Be the last of the big-time spenders. Buy the A500 at the lowest price you can find (maybe $180?) and take a chance on it. After all, it comes with a one-year warranty.
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