Two-Channel Stereo Is As Dead As the LP
By Tom Nousaine
(The High-Definition Weasel)
Major improvements in any performance- based technology, especially audio, come in quantum leaps. Fundamental leaps for communications were made possible by major advancements such as negative feedback, stereo, solid state, microelectronics, and digital storage formats. The architecture of the Home Theater system popularized by Dolby Pro Logic programs and high-quality multichannel decoders like the Lexicon have laid the basic foundation for the next major leap forward: discrete multichannel recordings. DVD is right around the corner.
Many folks will recoil at the suggestion of new formats because it suggests trashing all their existing equipment. Not true. Multichannel will be phased into existing systems just like stereo recordings and CD players. Some stuff eventually gets dumpstered (like my record-playing equipment), but most of it would be turned over eventually anyway. Just because.
So what's so special about multichannel?
First, Home Theater, with its basic multichannel architecture, has broken the “stereo as motorcycle” model. Second, the multichannel architecture brings better system implementation and setup, which improve even two-channel performance; and finally, it can be seen that the new format follows basic laws of natural progression in playback improvement. In between breakthrough developments, progress is seen through progressive changes that mainly reduce the price and improve the functionality and reliability of products. CD players, for example, have become much less expensive and sprouted improved functions like remote control and multiple play. They still all sound fantastic, although recordings have gotten much better because they are now recorded, mastered, and mixed for the new format. The first CD recordings were just reissues of stuff made for LP format release.
All you bikers know two-channel stereo is much like a motorcycle. You can have a passenger on a motorcycle, but only one person really gets the full experience. Stereo is a one-person party. Sweet-spot listening is the only way a stereo system can reach full potential. Period! Furthermore, using a top-quality stereo system is not a trivial task—how many of us have Do Not Touch and No User Serviceable Parts signs plastered all over our precious equipment? How many have family members who can actually use it? How many have families that are afraid to use it? How many have secreted the stereo in a separate room just to protect it from the prying fingers of family members? How many have family members who resent the money spent on Dad’s toy? Most, or maybe all, of us. The parallels with the motorcycle are painfully obvious.
Home Theater is different. The system is installed in the family room, where style isn’t an issue. Everybody uses it. Family members, even the wife, encourage resource deployment for Home Theater systems. You can even get home builders to include some of the basics in the price of the house!
Home Theater systems also bring important performance advantages with them because of their visual screen-based nature. First off, everybody agrees that a bigger picture is better. Bigger pictures mean bigger screens, which takes the heat off speaker size. A 50-inch tower speaker overwhelms the average living room but looks perfectly natural flanking a 50-inch rear-projection TV. Speakers are usually much more effectively installed in a Home Theater. The center channel is always on top of or under the screen, which gives new meaning to left and right. Because the TV sticks out into the room, speakers tend to be installed away from the rear wall in Home Theater systems—all without complaints from the family style consultant.
Listeners also become better placed. Because the system has a visual aspect, listening seats are dragged out into the room so viewers can see the screen. This means all listeners are facing the primary sound sources and may even be away from a nearby wall. Can you think of a time in the living room when putting a speaker or a chair out into the room wasn’t contested? And—the big improvement comes with having multiple listening seats, all with an acceptable image perspective. No more herding special guests into the sweet spot. No more grappling or fighting for the good seat.
The separate subwoofer architecture also brings performance advantages. Placing a full-bandwidth loudspeaker in locations that provide optimal spectral and spatial rendition compromises bass in most rooms. Because room modes are widely spaced at low frequencies, the best stereo locations also deliver a big hole in response somewhere between 30 and 50 Hz. For example in my room (12 by 22.25 by 8 feet) the best left, center, and right locations leave a big suckout at 35 Hz because the two lowest room modes occur at 25 Hz and 47 Hz. The fix is to put the subwoofer in a closed corner, where it excites enough multiple wall modes to fill in the hole at the main listening positions. Without a separate subwoofer you cannot position both the main channels and the bass optimally.
Finally, to get a major step function in performance we need more than two channels. It can easily be seen that two channels are better than monaural. Most of us have forgotten that stereo, as invented at Bell Labs in the ‘30s, was a three-channel format. Home Theater gave us the third channel back. What’s the next natural progression? Five channels. Then ten. The multichannel formats now available use five channels. So will DVD. Five channels are a major step forward in realism in the living room.
The move to five channels is far more important than all the samplingrate and bandwidth haggles going on, such as 96 kHz with 2 channels —no better than 44.1 kHz and stereo. DVD will use 48 kHz, which is more than adequate. Do we need more bits? Not for a media release. Sixteen has been more than adequate for over a decade now. More bits may be needed for production but not for consumer release formats. Loss-less coding? Not an issue. Data reduction? No problem. What we need is a minimum of five playback channels. Five discrete playback channels provide a solid, deep frontal image that remains stable for a number of listening positions, allows listener head movement, and fills the room with hall ambience that envelops the listener instead of clustering around the front channels.
Multichannel is the next big thing. It provides a major step up in playback performance and realism. The first programs will come from the movie people, as always. They dragged us into stereo in the ‘50s, matrix surround in the ‘80s, and are now dragging us into discrete multichannel with DTS and Dolby Digital. The established recording industry can be expected to drag their feet. Most of the several thousand extant recording studios are already at capacity making two-channel recordings, jingles, and commercials. They will see no reason to change anything until the multichannel recordings be- ing made on new digital workstations steal enough of their business to create excess capacity. When that juncture is reached, you will see a wholesale changeout.
How long will that take? Well, in 1984 we were predicting that CD would surpass LP in sales in a little over 10 years...about 1995. How long did it really take? Maybe five! I would say that by 2005 two-channel recording will be history. We will be having stereo “revivals” where the excess production capacity of fully amortized plants will have folks squeezing out the last few dollars from a dead technology, as they are now with tubes and LPs.
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