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

Aaron - I have Hyperion HPS-938 speakers that have very limited dealership in US. I bought it based on glowing reviews (6 month old dealer demo) without auditioning since I'm in Chicago and the closest dealer is in Pennsylvania. In worst case I would sell speakers but they turned to be absolutely great. Later I found that there is a website of Hyperion users that allow to audition in somebody's home.

I also, being an engineer, tend to over-analyze but I found things much more difficult (black magic?). I would even say that often amp with worse specifications has better sound. It has to do with how these specifications were obtained (negative feedback?) what is synergy with the rest of the system etc.
I tend to read editorial reviews but with a grain of salt. Stereophile reviews are always good and while they don't review non-advertisers they often compare gear. User's reviews and opinions here are great value to me (learning a lot).

I don't have any experience with subs but I'm sure others can help. One thing I noticed that extension is not automatically equal quality. My previous cheaper speakers had two 6" woofers while new ones have two 8" woofers in much larger cabinet but extension is worse (35Hz vs. 32Hz). What got better though, is bass quality - string attack and decay plus better tone and dynamics. I suspect that extension can be forced with extra driver and cross (like 2 1/2 crossover) or tuning of bass refleks. Bass refleks can also be tuned to minimize distortion (current speakers). Bass lower string is 42Hz while piano's is 27Hz but seldom used. For HT it is another story. My TV sound comes thru my system but the main purpose is music. I'm even afraid that sub might screw-up bass definition. There is also money allocation - good subs aren't cheap.

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?

My feeling is that the proper reconciliation of those two positions is that an understanding and assessment of specs is both useful and necessary in RULING OUT component selections that would be poor matches to either other components in the system (e.g., impedance incompatibilities, gain or level mismatches, etc.) or to the listener's requirements (e.g., peak volume capability, deep bass extension, physical characteristics, etc.). That hopefully allows the potential candidates to be narrowed down to a manageable number, and may allow some expensive mistakes to be avoided.

The list of remaining candidates can then be further narrowed either by listening, or if that is not possible by careful assessment of reviews and user comments (with grains of salt liberally applied).

Best regards,
-- Al

I am sure that in future, the set of measurments will predict fully amplifier behaivor.

Today, however, many measurments are meaningless or obtained by using dubious techniques design to improve measurments results and not sound.

Today, there are very few measurments which can preedict accurately what to expect e.g. headroom, bandwidth, lowest impedance the amplifier is stable and may be a few more.
THD is not but distortion spectrum will tell me a lot.

At any rate, DF is the ratio of speaker input impedance to amplifier output impedance at given frequency (I think 100 Hz but not sure) and can be achived, as Kijanki said by using deep slow negative feedback. I saw amplifiers, mostly class D with DF > 6000 which could not drive difficult load speakers.

I would suggest to trust "a bit" professional reviewers but more the amplifier's owners review - however, critically i.e. to see what speakers were used, what front end was used 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?