"Wylie Williams" wrote in message ...
I have read in many posts that once an electronic audio component
reaches a certain level any further improvement is inaudible. Not a point
of diminishing return, but a definite point of no further improvement.
Apparently these are knowns, but I have not seen much in the way of
specifics about these on RAHE. Or possibly they are old news and have been
well documented in previous discussions.
Is anyone willing and able to describe some criteria for determining at
least the general vicinity of this point ?

I will throw out some criteria, everyone is welcome to disagree with
me.

Signal to Noise ratio: That is fairly easy to determine, for yourself,
by listening to test a CD, with various white noise levels. White
noise of -60 dB begins to be difficult to hear. I find white noise of
-80 db inaudible. 16 bit CD's have a white noise less than -90 dB.

Harmonic and Intermodulation Distortion: If you can find his posts, I
remember John Dunlavy writing that tests showed -90 dB beat levels
were inaudible.

I would say that as a general rule, if the beats created by any
combination of three test tones are -90 dB, than the distortion
created by a music signal is inaudible.

Flatness: +/- 0.5 dB flatness (from 20 Hz to 20 kHz) is the point of
inaudibiliy.

Jitter: Some CD's may have more jitter than cheap CD players can
correct. Work needs to be done to determine the level of audibility
for jitter.

Transient Response: When tested with a squarewave, some amplifiers,
and most loudspeakers overshoot and ring to a stop. With amplifiers
and CD players the ringing can be zero. Only a few loudspeaker systems
have near zero ringing. I don't know the threshold of audibility for
ringing.

Since overshoot and ringing can be near zero for amplifiers and CD
players, that should be the required standard.

Loudspeaker Polar Response: No one seems to know the ideal polar
response for a loudspeaker. Since each living room is different, there
may never be an answer to this question.

Bob Stanton