The closest approach: what amplification?

" I do believe there is a reality out there that is objective, which defines the real thing"
Ah, to wax philosophic! Well yes and no, perhaps, we'll see. Sound waves are "real" in the material sense, but hearing is not. My teenager will be exposed to the same sound waves as I, but will he "hear" the same thing? How about a person from rural China? (A Chinese "opera", for that matter, is quite an experience). So much of what we hear is made up of learning, plus how our hearing actually works (a remarkable process in itself).
To go out on a limb, recognition is the key factor. We "hear" in the meaningful sense, when we recognize.
As a thought experiment I submit that if one were exposed to "perfect" sound wave patterns in a sufficiently unexpected context, that recognition would be so impeded that it would not take place at all. Our body might respond, but the brain would not "hear". On the other hand, if some one says: da, da, da daaa! the connection to Beethoven's Fifth may involuntarily pop into one's head.
(I hope you guys are having a beer while reading this.)
cheers

"Sound waves are "real" in the material sense, but hearing is not. My teenager will be exposed to the same sound waves as I, but will he "hear" the same thing? How about a person from rural China?"

Interesting, but I would argue that a machine that gets as close as possible to reproducing the "real" sound waves is what "the closest approach" is all about. Then I am less concerned about whether you and I perceive the same sound wave differently. That's unavoidable: my recognition of the real thing is different from yours, but the real thing exists independently of you and me. So, I guess the name of the game is reproducing actual sound waves. Don't yo think?

Back to amplifiers: There is general agreement about analog amplifiers. Solid state has the least distortion; the output resembles the input better than tubes. Are the tube folks all crazy? Do they like the sound of distortion? No they are not, but yes they do. Tubes compress the sound and they add harmonic distortion.
It is generally realized that our recordings are highly compressed of necessity. We simply cannot fit the sound waves of live music into our microphones, recording equipment, or our homes, so the recording engineers try to compensate to make the music sound more "natural". Among other topics, this gets us to the masking effect. Fairly slight changes in equalization can result in instruments or voices moving forward or back in the soundstage or even falling into a "hole". Engineers try to "correct" this. At 15% information recreation, recording is simply in the illusion business. Lots of folks like the illusion presented by the added distortion of tubes better than the more literal presentation of solid state. I suggest that the added harmonic distortion masks a good bit of the confusion of multi miking and of the room acoustics, but this is just a thought.

If you are going to make progress with audio, the first thing you have to do it look at the way the human ear perceives sound- IOW understand the rules of human hearing.

Unfortunately while the bench specs we are so used to were being developed, research was going on at the same time that proved that much of the bench specs were/are meaningless, but the audio industry chose to ignore this research.

Its a common phenomena to ignore things that appear to be small errors, but if you study chaos theory you find that you do this at your own risk! It turns out that the way the human ear perceives volume is not by the actual sound pressure of the sound in question, but instead by the trace amounts of certain odd-ordered harmonics, the 5th, 7th and 9th to be exact.

Any enhancement of these harmonics is instantly heard, even if only hundredths or thousandths of a percent!!

Global negative feedback, which is found in most amplifiers, **enhances** these very harmonics while otherwise reducing distortion. As a result, it can be safely said that added loop feedback to an amplifier will violate one of the fundamental rules of human hearing.

However the presence of distortion will mask detail and cause harshness (even with even-ordered harmonics) so you have to prevent it. Without loop feedback, this is a bit chanllenging, but it can be done: class A operation, Triodes, simple circuitry, fully balanced operation (cancels distortion throughout the amp) and an avoidance of things like pentodes, transistors and transformers that are known to increase distortion excessively is one technique.

Of course, such an amplifier will have a higher 'output impedance' but it turns out that the effectiveness of things like damping factor in speakers is highly qualified in any event. All speakers, if overdamped, will exhibit loss of bass (up to 8db) and transient detail, and how much damping an individual speaker needs can vary over a range from 0.1:1(!) to 20:1. However, there are no known speakers that benefit from more than about 20:1; something to keep in mind!

The point is that if a speaker cannot be driven by an amplifier that is in fact designed to obey human hearing rules, its likely that there is also no way that speaker will ever be heard to sound like real music. That should stand to reason, but I am always amazed at how many people point to bench specs- even when their own experience is that those very same specs tell them nothing about the sound of the amplifier in question! That alone should tell you that bench specs are measuring the wrong things :)

Some references: http://en.wikipedia.org/wiki/Chaos_theory

"Critical Damping: Missing Link in Speaker Operation Parts 1 & 2 http://www.pearl-hifi.com/06_Lit_Archive/07_Misc_Downloads/Misc_Downloads.html

"IOW understand the rules of human hearing" is surely an overstatement. Hearing evolved along with the brain, and our survival and social needs for eons. We are a very long way from a complete understanding how it interprets information.