Re: What's the use of a 192 kHz sample rate?

On May 4, 4:22=A0pm, "Arny Krueger" <ar...@[EMAIL PROTECTED]
> wrote:
> "robert bristow-johnson" <r...@[EMAIL PROTECTED]
> wrote
> in
messagenews:4f0de839-fa35-4c51-93c8-751c12118f79@[EMAIL PROTECTED]
>
=2E..
> > now this isn't what Bob Katz did, but it is what i wished
> > he did: called the original sound "A", and the LPFed
> > sound "B". =A0so sometimes the subject hears AA, sometimes
> > AB, sometimes BA, and sometimes BB (all four permutations
> > exist in equal quantity) and for each pair, the subject
> > simply has to say if they think the sounds are the same
> > or different. =A0every time a subject says that AA or BB
> > sound different, we count that as a false positive and
> > subtract that count from the number of times the subject
> > says that AB or BA sound different. likewise for false
> > negatives.
>
> That is called same/difference testing.

thanks, i'll use that term in the future.

> =A0It is an older form of testing,
> valid enough as far as it goes. The most im****tant question in a test is
n=
ot
> the order of presentation of variables (within reason) but rather
whether
> the listener can determine the identity of the so-called unknowns by any
> means other than listening.

that's what blind testing is about.

>
> > now Bob didn't do that, but he did something like it (i
> > think it was ABX) and there was no statistically measured
> > difference.
>
> At this point 100's if not 1,000s or perhaps even 10,000s of people have
> done this kind of test, and they obtained the same results as Katz.
Please=

> see www.pcabx.com.

i have never completely accepted that ABX testing is better than "same/
difference testing" (what i used to call "AB testing") for the
question we are trying to answer here.

ABX is for answering the question: which is better?  or which is
closer?  does synthesizer A sound more like a real piano or does
synthesizer B sound more like the real piano?

even though i am politically very liberal, as an engineer, i am *very*
conservative.  say the issue is Monster Cable.  the claim is that
Monster Cable sounds better than 10 gauge lamp cable.  now, being
conservative, i am willing to grant Monster Cable the benefit of doubt
in that if people can actually hear a *difference*, i'm willing to let
their claim that they sound better go without challenge.  but if
people *cannot* hear a difference, then i am not willing to accept,
even tentatively, that Monster Cable sounds better.  for it to sound
better, it has to at the very least, sound different.  since "better"
and "worse" is a subjective thing (like clean vinyl vs. CD), i am too
conservative to take a position regarding which is "better" if they're
different.  but i am not too conservative to say "bunk" about
something being experienced as "better" if it is not experienced as
different.

"same/difference testing" does not cloud the issue with an ancillary
question of "which one of these two sound closer to a third?"  it only
asks the question "do these sound discernably different or do they
not?"  and with same/difference testing, it is so easy to unbias the
measure so we can even invite a Monster Cable salesperson to the test
and let them know that if they guess with a bias that these sounds
*do* sound different (which would sup****t their case, but not fairly),
we will know it (because we subtract the false positives from the true
positives).  i think for this kind of question, the Monster Cable
sounds better or ultra-high sampling rates sound better or whatever,
same/difference testing speaks to that question directly whereas ABX
is not as direct.

r b-j