Hum.
First, welcome to the forum.
Glad you like your Mojo.
But, I have to admit this last part is very confusing to me. What are
those power amps you're mentioning? May you explain how you distinguish measurements from sound? Your last sentence especially, seems to mean that
engineering and
sound are two discinct parts or entities.
Hi sorry it took some time to reply - I am often traveling for business.
I try to make the last part clearer. In the 80s some SS amplifiers were developed, like the Adcom GFA555, some of the early NAIM power amps, Yamaha P3500S and others, that were know to have (some) good measurements, yet sounded, arguably, bad - for the Adcom lack of dynamics and detail, and so on. The good measurements were obtained by essentially taking a poor amp and applying gobs of negative feedback.
Today we measure more things, for instance besides THD we also measure IMD, whereas TID is somewhat fallen in disgrace. There are also known memory effects of several electronic components that may affect the sound up to a few seconds later. What we do today is we measure still only some low order effects, but not the behaviour when the amplitude of a signal changes repeatedly, rarely IMD with several signals, also varying.
Yet, some very good measuring amps apparently have poor macro dynamics, for instance sudden orchestral fortissimo tutti sound suddenly muffled, why is that? In some cases one can easily hear that. Of course I know I should accepted nothing that is not doubly blind, but I believe I have enough evidence of that.
And herein lies what I meant. Good Engineering and good sound are clearly correlated, but not always 100%. If someone wants to design equipment for good measurements, this cannot be wrong as this is necessary to get good sound, but maybe there is something else, and there are
clues, rather than proofs, that this may be the case. The clues are what apparently can be heard but not (yet) measured. A scientific mind cannot but inquiry this.
Of course measurements and perception can also go opposite ways. For instance now we know that a larger scene can be created by audible IMD (and once you see that, it becomes obvious) so in this case a better measurement can correlate with a subjectively "worse" sound, because we attribute value to something that is actually not in the signal...
Roberto
