You seem to be seriously confusing my posts with someone else.
As you say - I work for a company who makes amplifiers - among other things.
And I can tell you that no two of our models have ever measured
EXACTLY the same.
There are always tiny differences in frequency response, or THD, or the actual spectrum of the tiny amount of THD that's present... or any of a dozen other things.
And, yes, in many cases, even though they measure slightly differently, at least to me.)
I am also the first one to agree that
ANYTHING that can be heard
can be measured.
And there is absolutely, positively, NOT any such thing as magic.
However......
If you hear a difference, but can't seem to find a measurement that would account for it....
- maybe you're simply not measuring the right thing
- maybe you're not measuring it accurately, or carefully enough, or under the right circumstances
- maybe you're not interpreting one of the measurements you've taken correctly
- (and, yes, maybe you were just imagining it)
But, just maybe, the 0.2% THD, which you're quite certain couldn't possibly be audible, really
IS audible under certain circumstances.
This was commonly the case back in the early days of amplifier design.
An imperfect Class B output stage will often exhibit "crossover notch distortion".
This is typically a "spike" of distortion that occurs right around the zero crossing point of the waveform.
(At certain instants, the signal that should be present is entirely missing, which calculates to a very high percentage of distortion.)
The result is a very high level of distortion - but for a very short duration - and a very small
percentage of the time.
And, if you look at the waveform on an oscilloscope, the flats around the zero-crossings with be quite obvious.
However, if you measure the THD, using standard techniques for doing so, the readings will be quite low.
THD is an averaged reading... and very short spikes of high distortion average out to a low overall value.
However, if you look at the THD reading, and fail to look at the oscilloscope, you will reach an entirely erroneous conclusion.
(And, more to the point, if, after seeing the THD reading, you'd concluded that "they must be imagining that it sounds harsh", you would never have discovered the truth.)
My point, in the very general sense, is simply this....
If what you think you hear seems to disagree with the measurements...
You should consider taking a few more measurements...
Or even, perhaps, examining the situation a little more closely, and attempting to figure out what you might have missed...
Instead of just discounting what you heard as "something that couldn't possibly be true"...
I consider this to be even more true with modern digital devices like DACs.
The possible distortion mechanisms for this sort of equipment are much more complex than those amplifiers are subject to.
And, with digital components, it's not at all unlikely that new sorts of artifacts and aberrations may occur.
How
DO you count the "distortion percentage" of ringing (where output signal is present when there was no input signal).
And how do you rate the audibility of pre-ringing.... where output signal is present
BEFORE the input signal that caused it.
And how do you determine the "THD" on a lossy file - where entire complex sounds are omitted after being calculated to be "inaudible"?
(For example, an amplifier with 50% THD sounds audibly
MUCH worse than an MP3 file where 50% of the information has been omitted by the encoder.)
The previous simple metrics for what's audible simply cannot reasonably be
ASSUMED to apply to these sorts of situations.
So we need more testing, in order to develop new metrics, which do apply, and which do correlate to what we hear.
(And, no, the basic theories behind "rocket science" are actually pretty simple... and a lot of this stuff is in contrast quite complex.)
And, incidentally, in the "grand audiophile scheme of things", and of comparing various products at different price points....
The company I work for, Emotiva, is generally the one offering "the economical model with the good performance", and not "the expensive audiophile model".
(So, if you want to ask "what makes the expensive one sound better", that would probably be a question for someone else.)
yup. And they found the explanation (which had nothing to do with the expensive one sounding "better" than the cheaper one.) Which is all anyone wants from you. Show us the data. Show us the (audible by human ears) difference between your expensive amp and the lesser one. Don't just say "I can hear the difference." You are an amp manufacturer right?? Surely you can show us the measurements you've taken that explain what you say you hear. If two things sound different, something as simple as a frequency response graph will show that right? This ain't rocket science. But no, instead of providing that you fall back on what amounts to "it's magic and there's no real way to explain it." Amps don't have to sound the same. They can be made to sound how ever the designer wants them to sound...but that isn't really what most of us want right? We want amps that take a signal in, amplify it cleanly, and then pass it on to the speakers. So given two amps that both profess do that, what makes your more expensive one sound better?
