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

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.

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.

Atkinson's measurements are with steady-state signals. They tell you *something*, but how the amp behaves with a non-repetitive waveform is really much more important. In my opinion.

Aewhistory, you might be surprised to find out that research about the way the ear hears and how the audio system interacts with that, has really not been dealt with all that much in a way that is not classified.

I have heard of some research that has been done recently (in the last 3 years) that shows that if human hearing rules are not respected by the audio system, the process of analyzing the music by the brain moves from the one area to another. To be more specific, if the waveform is fast enough and lacking manipulation, the limbic system does the processing, but if too slow and certain harmonics are added, the processing is done by the cerebral cortex (emotional vs intellectual). I understand that they have hard numbers on that- on where the transitions occur. Fascinating stuff!

Seriously, I doubt that anyone could make serious progress in an audio design without understanding how the human ear/brain system works.

Some of this research is very new. The bit that I mentioned about how the processing moves from one part of the brain to another has only been done in the last 2-3 years. Intuitively, I think a lot of designers suspected something like that, hence some systems that invoke toe-tapping and the like; but its nice now to find out that the subjective experience is real and to have objective numbers to back it up.

That, IMO, is what the objective approach **should** be. Otherwise, the bench measurement rules amounts to the Emperor's New Clothes.

Aewhistory, for the most part I think you will find that a low THD indicates a greater amount of feedback (with it accompanying distortion of the 5th, 7th and 9th harmonics) rather than a 'cleaner' signal path.

IOW, if anything it appears that there is a loose correlation saying that higher THD will sound *better* not worse- and likely having a 'cleaner' signal path, hence less need for feedback. The 'cleanest' signal path will have no need for feedback. Note: this is neither a tube or transistor distinction.

Kijanki, IME wide bandwidth is important due to low phase shift, barring that, then gentle rolloffs as opposed to steep ones. I use an Alesis Masterlink in the recording studio for backup recordings. It can record at 88KHz, which is nice as when you use that mode, there is no brickwall filter. As a result the 44.1 KHz finished product does sound better on that account. I think things like this and what you just described are where the advances in digital are occurring- no doubt due to our improved understanding of how the ear works.