Amp Specs esp. DampFactor : Citation, Adcom, etc.

Some folks are passionately against using specs in judging equipment and others, albeit a smaller group IMO, are just a passionate that specs/performance should be measurable. Personally, I'm a military historian and tend to be analytical, so while I can appreciate both sides of the debate, the end result frustrates me. So my main question is in trying to understand the two sides, or rather how do I reconcile these two positions?

This is actually fairly simple. The answer is that the specs were devised about 40-45 years ago, when very little was known about how the human ear perceives sound. A lot of research has been done since then, but none of it has been incorporated into the tradition of measurement, and so we have the experience of not being able to tell much of anything about the sound of the amp from its spec.

IOW, we don't measure what is important to the human ear.

This is what has led to the objectivist/subjectivist debate, although the issue is a bit larger and more complex than that. See
http://www.atma-sphere.com/papers/paradigm_paper2.html
for more information.

Just a FWIW, Damping factor is the least of your worries in any solid state amp. I would not worry about distortion either, Kijanki is correct in his initial post.

"we don't measure what is important to the human ear"

Atmasphere - absolutely true but how we can measure it? I don't know how to measure amp's music power or how to measure TIM distortion or how to guarantee synergy with the speakers. Is there anything we can do (new standards) or it will be always black magic?

I think there is. This is just my opinion of course, but I think we need a standard signal burst, one that last for about 1 second or so, that is completely non-repetative.

The instrument would then compare the amplifier's output to the original. The result would be examined for odd-ordered harmonics so a listener fatigue/brightness rating can be assigned. Then the lower ordered harmonics can be analyzed so a low-order coloration (warmth, caramel, syrupy) value can be assigned.

It would be nice to do this with a variety of test loads, both linear and nonlinear.

That's where *I'd* like to start anyway. I think there is no reason why such a test could not be devised- the compute power for that is pretty common these days.

Atmasphere, at the risk of sounding completely ignorant... why hasn't somebody done what you're proposing? This sounds brilliant, simple, and straightforward. In fact, I'd think that this sort of testing would supply much of the sort of information that I'm looking for.

It isn't that I disagree that each piece of equipment won't sound different, and I certainly agree that what sounds 'good' is subjective, but the methodology behind the sound reproduction should be measurable meaning that it should be possible to say something like: okay, you are looking for this sort of sound, for this sort of speaker, etc. Then you should be looking for amps with these characteristics.

The problem as I see it right now is that if none of these measurements have any value, then how can any of these judgments be made. This is why, at least in part, I think your idea is great.

One last note: about not measuring what is important to the human ear. I'm going to go out on a limb and say that this is likely not true. I can't say for sure, but in my field I research a fair amount of psychology regarding military deterrence and I am constantly impressed at how far the psychological and biological sciences have come in recent years. My point is that I would be shocked if no one has studied the interaction of the human brain, our in-built hearing, and how it interacts with music. Any study such as this would lead, inexorably, toward a better understanding of what appeals to the human ear (in general) and what does not. There are cultural issues here besides biological ones, but momentarily putting these aside, I believe you'd find that, in fact, what we hear, how we hear, and why we like certain things can be measured to a certain degree. To extrapolate, this would explain why certain types of sound reproduction--maybe using tubes?--remains popular even though arguably inferior technologically.

"...The result would be examined for odd-ordered harmonics so a listener fatigue/brightness rating can be assigned. Then the lower ordered harmonics can be analyzed so a low-order coloration (warmth, caramel, syrupy) value can be assigned. "

I believe that John Atkinson from Stereophile does this kind of measurments (his input signal can be subject of discussion) and looking on distortion spectrum - as you discuss above - I have some idea of the sound of the equipment - at least its midrange.

"A lot of research has been done since then, but none of it has been incorporated into the tradition of measurement, and so we have the experience of not being able to tell much of anything about the sound of the amp from its spec."

Simon Thacher from Spectron did study of the rlation between reproduction of musical peaks and listener fatique:
http://www.enjoythemusic.com/magazine/manufacture/0708/index.html

I beleive that Spectron amps are one of the best in that regard - of course, for easy load speakers you don;t need that amount of (distortion-free) power.

So, slowly but we still are moving along to understand relation between some measurments and some aspects of the sound.

Cheers