Atma-Sphere Class D… Amazing

Strictly speaking, Fletcher-Munson and the like are not rules or laws, but rather experimentally derived models of human aural perception. They are built on averages and generalities- in the case of Fletcher-Munson the results are said to apply to "average young people without significant hearing impairment". I doubt that describes many of those reading this thread... They have also been revised numerous times. While these rules of thumb are helpful perhaps to people such as yourself designing amplifiers aimed at as broad a segment of the market as possible, they are not "laws" or universally applicable "truths" like …

In terms of universal truths and laws, one can pretty safely say that as the distortion products go to zero, that the fidelity improves. How well this happens with complex loads, etc. is where topologies matter. But if we assume that some amps were possible with a vanishingly low THD+N, then they would sound the same regales of topology

… the law of conservation of energy or the laws of thermodynamics. As a result, they can not be relied upon on to be an accurate predictor on an individual basis.

Statistics, stereotype and generalities are borne from things being similar.
Humans are tuned to those sorts of easy ways to categorise things.
And the statistics of a group, are indicative if the sum of the individual biases and likes/dislikes. 

Thus, the guy shelling out $5K for an amp would be best advised to trust his own perceptions and tastes and to listen to the amp in his system, in his room, to form his opinions rather than rely on the perceptions, tastes, and opinions of others. Of course there are always those who love to gamble.

And thus if one considers themselves similar to others in the group, then they would be more wise to gamble that what other people like, that they will also find that they the same stuff.
and likewise if they find that they are at odds with the group, then they would likely deviate from the group perspective.

An example would be cable deniers or believers.

1. If one identifies as a cable believer, then other cable believer perspectives likely have more bearing, and theuy find speaker cables, IC and power cables all matter.
2. And for the cable denier, they likely find similarity with other cable deniers, and value their similar group’s inputs.
3. and some probably find no difference in XLRs and power cords, but could believe that speaker cables make a difference, and identify with their brethren/sisters.

@holmz

But if we assume that some amps were possible with a vanishingly low THD+N, then they would sound the same regales of topology

There are indeed those who claim once a certain level of performance has been reached, then products would indeed be indistinguishable from one another. I believe there have been rather rigorous tests done which seem to bear this out.

As I said, Fletcher-Munson and other such empirical studies have predictive power in a general sense but are weak on an individual basis. Additionally, personal preferences when it comes to audio gear is not based solely on sound, in any case. There are several other factors buyers consider when making a purchase which factor into a decision. It’s a complex decision that one needs to ultimately make for one’s self in the proper context.

Sure, a person could choose a proxy and take a chance. It all depends on risk tolerance and finding a suitable proxy. Me, I prefer to judge for myself as finding someone else with my tastes, the same gear and acoustical space, would be more difficult, time consuming, and risky than just trying the equipment myself. Besides, even if I associated myself with a "like minded group", the critical issues of component interaction and acoustical interaction in my space would make it impossible to find a realistically "safe" bet.

I don't believe your analogy is appropriate, either for those  "cable deniers" who base their argument primarily on an intellectual argument- it's a belief system, not a perception driven matter of taste, nor for those who simply claim that they hear no differences. That is more a pure perception argument rather than a matter of taste. In either case, it isn't a simple matter of taste at work, unlike the debates centered on amps, etc.

@kuribo generally agree, but what is your point?

• Is it that you want to see specs?
• Or listen to it?

Or what am I missing?

If a bunch of people with speaker-X say that they like electronics-A, B and C, then I think to myself, “I should see if I like them.”
If I do not like speaker-Y and a bunch of people say electronics-C, D, and E are great, then and not sure what I should with that… especially with D and E.
 

As there are more electronics that one can often stumble across we use other peoples observations and opinions on a forum to make some sense of it, and get exposed to things which we may not find, or otherwise know to look for.

@holmz


I would have thought by now my point had been made.

Yes to both your questions.

No harm in using forums to learn of new gear. One needs to read critically and take the subjective opinions with a grain of salt. When it is all subjective opinion there isn’t much sense that can be made of it if you are a rational actor. Too many don't understand the difference between their subjective opinions and objective fact.

While these rules of thumb are helpful perhaps to people such as yourself designing amplifiers aimed at as broad a segment of the market as possible, they are not "laws" or universally applicable "truths" like the law of conservation of energy or the laws of thermodynamics. As a result, they can not be relied upon on to be an accurate predictor on an individual basis. Thus, the guy shelling out $5K for an amp would be best advised to trust his own perceptions and tastes and to listen to the amp in his system, in his room, to form his opinions rather than rely on the perceptions, tastes, and opinions of others.

Fletcher Munson is a bit more variable, but the masking principle isn't. Its what made MP3s possible. Also, how humans sense sound pressure does not change from individual to individual; generally, the higher ordered harmonics are used. This is really easy to demonstrate using simple test equipment.  Imagine a world where every individual used entirely different hearing perceptual rules! It would be a good basis for a scifi novel 😉

The patent involves the use of a Circlotron to reduce deadtime. If you are using GaNFETs, the inductive kick of the output filter coil is what really turns the device off (assuming the gate is already off); to allow that to happen a certain amount of deadtime has to exist. As it is there is still less deadtime in a GaNFET design as opposed to a MOSFET design.

Too many don't understand the difference between their subjective opinions and objective fact.

Being objective is a worthy struggle despite it being impossible.

FWIW we've done lots of comparisons and we have a lot of feedback from the field at this point- from a variety of customers that know our prior work. The feedback is surprisingly consistent, in the face of not knowing about any other feedback we've received.