[Doug McDonald[_3_]]

Sonnova wrote:


Yep. When making any kind of sonic evaluation, one must be careful to match
all levels exactly. If one device under test is even subliminally louder than
another, that's the one that the ear will favor as being the better of the
devices under evaluation. This holds true for signal sources, amplifiying
devices as well as speakers.

I simply do not understand this. Why should exact level make any
difference in tests of quality. Sure, if you are trying to tell if you
can tell ANY difference between systems, it matters ... you could have two absolutely
identical systems, that were indistinguishable if level matched,
and if they were off by 0.5 dB anybody coll tell them
apart. But it would be impossible to tell
qich was "better" since they would be the same. I've tried such
tests, and indeed it is impossible to tell which is better even if
not level matched.

Approximate level matching might also be important
if two systems differed only in frequency response (in which case,
of course, exact level matching would be impossible,
for all frequency bands!) But if two system actually had
other differences (distortion) it should be noticed even
if the levels were only approximately matched. I've tried such tests too, and
the level matching did not matter. Of course, it is true that I was
unable to hear differences that other claimed to hear. Maybe
I have a tin ear, but I doubt it (other of course than being old.)

Doug MCDonald