wrote in message
ink.net...
:
: "Clyde Slick" wrote in message
: ...
: It most certainly is an assumption.
: I heard differences you are neither able to hear nor to measure.
: Buy a hearing aid, or come up with some better ways to measure.
:
: If they can't be measured they can't be heard either.
:
:
Maybe so. However, the same problem that plagues abX is at hand he
you can measure temperature, relative humidity, illumination level and
what not, how are the results relevant to the question of difference ?
Iow, to state that some measurements or metric are relevant do not
make it so. Usually, not relevance, but convenience and available
measurement equipment have set the standard and type of measurements :-)

THD, for instance, is calculated with a summing of the squared levels of
the various harmonic distortions - not at all a correct weighing of the actual
perception of 'aggravation' by these distortion components - as is known
for decades

At a more fundamental level, the mental model of having some
pristine signal and a separate 'distortion level treshold function' in the
listener is just not the way perception works. So while at some instances,
as little as 0.03 % distortion is clearly noticeable*, at other times, several
percent will pass by unnoticed**.

Under dynamic conditions, that is, with music, things like time domain and
frequency domain masking take place. Many perception modifiers
(i prefer that to the rather loaded-with-connotations-term bias) are at work,
whether sighted, blinded, double or tripled, whatever ;-) listening is done,
making it an individual experience that cannot readily be lumped together:
that would make as much sense as saying that the average taste preference
is "red herring with sour cream and strawberry ice on top".

Of course, distortion is just one aspect, frequency range, frequency response,
noise, output impedance, horizontal and vertical dispersion vs. frequency,
sensitivity, pulse response, compression, jitter are some other metrics that are
applicable with some of the components in the audio reproduction chain.

Your claim to know "what one is able to hear" is highly suspect.
It would also render a lot of testing and evaluation in the real world rather
pointless, as it could then be established from a simple set of measurements,
some metric, fed into some weighing matrix and..presto audible or non-audible
comes out -- i think NOT.

Rudy

* in a 1000 Hz sine wave, in a carefully set up university experiment, by some of
the participants..others had trouble with anything under 0.5 % :-)
** playing back music, containing 30 - 60 Hz components at reasonably loud
levels, all speakers will give you such distortion levels (except some megasized
woofers