"Polyamping" A Look to the Future or Fancy Fad?

Some interesting comments.

Bob, I was not singling out that an ATI amp be used, just that such was sugeested in the design by the designer. I have no knowledge of these amps personally. It was the only design in the DIY realm that I saw which incorporated use of a mutli-channel amp.

Sean and Gregm, your comments with respect to sufficient power are intriguing. How would the 60w not be enough for quality bass response when others claim to get such even with very low wattage amps? I am not saying you're wrong, just asking because I don't know.

Sorry if I overlooked designs of the past that used this design scheme. It was the first I've come across that really went beyond biamping in what seemed to me a radical way. But then, I haven't been auditioning dozens of speaker designs over dozens of years. Because Linkwitz is considered to be rather an innovator, I wondered if his design might be a direction for the future. If such has been done before, though, it wouldn't be the first notion of a technology or approach in audio that was relagated to "dinosaur" status, only to raise its head triumphantly at some point in the future. I'd say analog front ends are an example that many here are familiar with.

The new Pass Labs speakers use this approach. Several "Aleph" style amps internal to each speaker. $40k price tag, but they sounded quite good at CES.

-Ed

Ha, I was going to say that no discussion on this issue would be complete without some input from Sean, but I see that, as usual, he's way ahead of me....

Mezmo: While i appreciate the vote of confidence, don't encourage me. I already open my mouth too much as it is. Just ask Brulee....

4Yanx: What is good for the goose is not always good for the gander i.e. personal preference rules. Once you've heard "commanding" bass with impact, definition, authority AND control, you'll know where Greg and others like us come from. You might be amazed at how much power high amplitude reproduction of low frequencies actually takes to do "right". This is especially true if you have low efficiency speakers.

To try and explain this simply, the more excursion that a driver has to make, the greater the distortion and the poorer the transient response. As such, using multiple drivers allows one to move as much air without any individual driver ever having to make much of an excursion. They are all sharing the load rather than having to deal with the physical / electrical demands individually.

This is the approach that Dr Bose took with the original 901's and Bill Duddleston likes to promote in the literature of Legacy products. While such an approach is very valid, you now run into problems with impedances and high levels of reflected EMF*. As far as dealing with low impedances and higher levels of reflected EMF, it takes "muscle" to deliver the power required to control all of the drivers and deal with the reflected EMF.

Bob Carver does a good job of explaining this in the white papers of his Sunfire subs and i encourage those interested in learning about such things to give those a read. He tries to keep things simple yet get the point across. You don't have to like the product to understad that there is a a lot of valid research behind it. As is so often the case, the good intentions and valid research get lost somewhere along the production lines.

To those that that think that "high power" is unnecessary, i'll use the same analogy that i use at work all the time.

If you've been walking all of your life with no other means of travel, a bicycle seems great. When you start driving a Yugo, the Yugo makes the bicycle seem antiquated and slow. When you start driving Lincoln's, Cadillac's, Mercede's, BMW, Porsche, Ferrari, etc... everything else prior to that point seems like a joke. You look back and wonder why it took you so long to understand your current vantage point and realize how much better it could have been and / or how much you've missed along the way.

While we call this "the learning curve", it is all a matter of perspective, experience and personal preference. As such, "good" results to Billy Bob might be "piss poor & pathetic" to Ray-Ray : ) Sean
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*This is not to mention a slew of other problems that are related with acoustics / room loading, but that is a whole 'nother ball of wax.

PS... i was able to mention Bose, Legacy and Carver all in the same post in a positive manner. That must be a first for Audiogon : )

If you mean by "a look into the future" that amps will be manufactured in mult-two-channel construction, then I would disagree with it being a trend - too expensive for mass consumption. One if the caveats of mult-amping is that all amps have the identical gain (or withing 0.5%), which basically means using identical amps. If the price of two-chanel or mono amps goes up exponentionally with sound quality, then the prices will climb (linearly??) for each set of channels.

In this regard, I agree with it being one of diminishing returns, and with the price of top notch amplification up in the stratosphere, the question is: when does, for example, multiple Brand X mono pairs equal the performance of a one pair Brand Y. An interesting calculus problem.