(ludovic mirabel) wrote in message news:nsd3b.276882$o%2.127236@sccrnsc02...
"Wylie Williams" wrote in message ...
"Nousaine" wrote in message
. net...
"Wylie Williams" wrote:

See previous discussion below:

Why don't you or Harry include bias controlled listening in your methods?
It's
not that hard. Be more inclusive and tolerant.

"
"It's not that hard?" Reading RAHE posts makes it look like a very
involved process, especially since RAHE members argue at length about the
validity of the methods, the conduct of the tests, and the credibility of
the results.
But if there is a simple method I would like to see instructions. I
am considering comparing three amps I own. Normally I would have just
substited and listened to each a few days, comparing opinions with my wife
as we went along, but I will consider bias controlled listening.
Wylie Williams

At a risk of stirring up a hornets' nest here is a protocol I
use because I find that the task of remembering A, then remembering B,
and finally comparing X with my memories of A and B results in
complete confusion and random guessing,
I want a synchronous, simultaneous comparison with no
memorisation required.
This is me and I guess some others too. I will not repeat the
evidence from the past records that there could be many others like
myself accounting for the uniformly negative results of the recorded
and published ABX component tests audiophile panels.
I want to emphasize that I have nothing against anyone using
the ABX approach if they feel comfortable with it, have the required
ABX switch, a voltmeter for exact levelling etc.

My approach centers frankly on preference. Insisting on
"difference and difference only" may be a prerequisite in research. An
audiophile wants help to exercise his consumer choice.
Secondly, while roughly level volumes between the left and
right side are desirable. Very exact levelling is not necessary.
Other common sense precautions a compare like with like:
testing a 400watt amp against a 5watt SET is waste of time.
You can not compare signal source against signal source this
way ie. a cdplayer against a cdplayer, turntable against a turntable.
You cannot compare speakers because that requires special
facilities for moving them fast to an exact position . Same of course
applies to ABX testing.
You can compare interconnects, power cables and power
controllers, interconnects, preamps, amps, dacs.
An obliging partner is a necessity.

1) Get a monophonic or near monophonic (eg. centred soprano) signal
source. MUSICAL, not an artefact.
2) On the left insert one component, on the right the OTHER ONE- (in
the case of interconnects using two of one kind together i.e.source to
preamp and preamp to amp on each side will give better contrast.)
3) Listen -write down your preference, get blinded.
4) An assistant now changes AT RANDOM (coin throw) both components
from one side to the other or (of course) leaves them where they are
keeping the records.
5) This is repeated minimum 15 times- for any length of time and with
interval for lunch if you like. EVERY TIME you note your
preference
The repetition and change are the CRUX.

At this point INVARIABLY someone says: No good, room sides differ,
levels differ subtly etc.
Answer;If there are differences between room sides, speaker volumes
etc. and yet you still prefer and locate one of the two component as
it moves from side to side surely, that REINFORCES the results- yes?
no?
Eg. The bass is distorted on one side of your room but you still
have a statistically significant positive results: "I prefer the sound
of this preamp on EITHER side."
The other theoretical objections from the people who never tried it
are of little interest. The inferences from other fields (eg.
research)
are even less so. Apples and oranges. Even if they assure you that the
Goddess of their kind of "science" is fighting on their side.
The comparison is not just supposedly "instantaneous"- it is
SIMULTANEOUS.
While comparing turn your head from side to side as much as you like.
If you have no preference give the component back to the shop. If
there is any difference it is not one that matters to you
=(Proviso)- at this stage of your musical experience and preference.
Exactly like is the case with an ABX result
NB. This is not a universally applicable "test". It is a method
that suits me because it involves no memory feats that are beyond me
and many others. I have no universal "scientific" pretensions. I only
use it to reassure myself that I'm not a victim of delusionary bias.
Those who are comfortable with ABX are of course welcome to it.
Ludovic Mirabel

If I were a con artist, and wanted to "prove" how acute my hearing
was, this is exactly the method I would use. It's really quite clever
for that purpose. Because the two sides aren't level-matched, it would
be easy to tell when the two sides had been switched. (The image
appears in a different place!) All one has to do is declare a
"preference" on the first trial. After that, since you'll always be
able to tell when the switch has been made, it's hardly a challenge to
declare the same "preference" repeatedly. No wonder you've impressed
your friends with this trick.

Now, why don't you try it level-matched, and double-blind, and then
submit an article to JAES (or even S&V!), so we can see what the
results really are?

bob

(Bob Marcus) wrote in message t.net...
(ludovic mirabel) wrote in message news:nsd3b.276882$o%2.127236@sccrnsc02...

See initial discussion below:
Mr. Marcus responds:
If I were a con artist, and wanted to "prove" how acute my hearing
was, this is exactly the method I would use. It's really quite clever
for that purpose. Because the two sides aren't level-matched, it would
be easy to tell when the two sides had been switched. (The image
appears in a different place!) All one has to do is declare a
"preference" on the first trial. After that, since you'll always be
able to tell when the switch has been made, it's hardly a challenge to
declare the same "preference" repeatedly. No wonder you've impressed
your friends with this trick.

Now, why don't you try it level-matched, and double-blind, and then
submit an article to JAES (or even S&V!), so we can see what the
results really are?

bob

Mr. Marcus you give me too much credit. Con artist I may be but
I'm not a magician- the two SIDES are NOT switched- only the
components are.
The room stays where it was. Any differences between its two SIDES
stay where they were, the speakers, the cd.player or the turntable
stay where they were.
The only things switched are the two components-two links
between the sound source and the speakers. They are moved from one
SIDE to the other SIDE And these components should be as level-
comparable as the components were in all the published ABX component
comparison tests- all of them with negative outcomes.
The levels must be close to begin with because TO BEGIN WITH
YOU ADJUST THE LEFT AND RIGHT VOLUMES ON YOUR PREAMP TILL THE MONO
IMAGE IS DEAD CENTRE. If you had much experience with voltmeter you'd
know that very little decibel difference namely 0,5 db. moves the
image right or left. Nothing against using a voltmeter- I got no
revelations when I did.
One needs a particular kind of imagination and /or limited
experience to believe that such kindergarten precautions don't occur
to others.
The monophonic image stays solid with component changes. At
least it does in my room- which does not rotate short of three glasses
of Cognac. How about yours? Does the earth move when you ABX at home?
Mercy- I nearly forgot. Greenhill in his ABX panel cable
testing had TWO out of SIX positive results but ONLY when he was
comparing a thick and a thin cable with 1,75 db. level difference
between them- and ONLY when using pink noise for his signal- not
music.
These two results are immortalised as "Marcus-Ovchain positive
1,75db. test" because you claimed it as your one and only evidence
that ABX can give positive results when comparing components and
Ovchain was applauding on the sidelines. That explains why you think
that 1,75 db at say 4000hz would be missed by anyone not terminally
deaf. For your information- these old ears detect a 0,5 db change in
volume when switching my stepped volume controls.
I promise to reflect on your con artistry connoisseurship in
my spare time.
Ludovic Mirabel
P.S. I'll contact JAES after you quote one single ABX
component comparison report that appeared there.
While waiting I described the left-right method in an article
in a Guest Editorial in the "Audio Electronics" #5, '98, p6.
I'll mail the Editor your posting . He'll be saddened to hear
how foolish he was to fall for my con act, and no doubt invite you to
contribute as a scientist-vigilante on psychometrics, acoustics,
electronics etc.

(ludovic mirabel) wrote in message news:xDA3b.220180$cF.73109@rwcrnsc53...
(Bob Marcus) wrote in message t.net...
(ludovic mirabel) wrote in message news:nsd3b.276882$o%2.127236@sccrnsc02...

See initial discussion below:
Mr. Marcus responds:
If I were a con artist, and wanted to "prove" how acute my hearing
was, this is exactly the method I would use. It's really quite clever
for that purpose. Because the two sides aren't level-matched, it would
be easy to tell when the two sides had been switched. (The image
appears in a different place!) All one has to do is declare a
"preference" on the first trial. After that, since you'll always be
able to tell when the switch has been made, it's hardly a challenge to
declare the same "preference" repeatedly. No wonder you've impressed
your friends with this trick.

Now, why don't you try it level-matched, and double-blind, and then
submit an article to JAES (or even S&V!), so we can see what the
results really are?

bob

Mr. Marcus you give me too much credit. Con artist I may be

Actually, I don't think you're conning anyone.

but
I'm not a magician- the two SIDES are NOT switched- only the
components are.
The room stays where it was. Any differences between its two SIDES
stay where they were, the speakers, the cd.player or the turntable
stay where they were.
The only things switched are the two components-two links
between the sound source and the speakers. They are moved from one
SIDE to the other SIDE And these components should be as level-
comparable as the components were in all the published ABX component
comparison tests- all of them with negative outcomes.

Ah, so you do level-match them. I thought you said that wasn't
necessary.

The levels must be close to begin with because TO BEGIN WITH
YOU ADJUST THE LEFT AND RIGHT VOLUMES ON YOUR PREAMP TILL THE MONO
IMAGE IS DEAD CENTRE. If you had much experience with voltmeter you'd
know that very little decibel difference namely 0,5 db. moves the
image right or left. Nothing against using a voltmeter- I got no
revelations when I did.

But you used one, right? Because you absolutely have to, you know. Or
rather, your lovely assistant has to, because if YOU adjusted levels
after SHE switched the components, it wouldn't even be single-blind,
now would it?

One needs a particular kind of imagination and /or limited
experience to believe that such kindergarten precautions don't occur
to others.

If all you're using are kindergarten precautions, I'm afraid we have a
bias control problem.

The monophonic image stays solid with component changes. At
least it does in my room- which does not rotate short of three glasses
of Cognac. How about yours? Does the earth move when you ABX at home?

Do it double-blind with an impartial witness, and show us the data.

Mercy- I nearly forgot. Greenhill in his ABX panel cable
testing had TWO out of SIX positive results but ONLY when he was
comparing a thick and a thin cable with 1,75 db. level difference
between them- and ONLY when using pink noise for his signal- not
music.
These two results are immortalised as "Marcus-Ovchain positive
1,75db. test" because you claimed it as your one and only evidence
that ABX can give positive results when comparing components and
Ovchain was applauding on the sidelines. That explains why you think
that 1,75 db at say 4000hz would be missed by anyone not terminally
deaf. For your information- these old ears detect a 0,5 db change in
volume when switching my stepped volume controls.

I am quite through trying to argue with you about Greenhill's tests.
Everything you have written about them has been wrong (save, perhaps,
the date of publication), and although you have been corrected many
times by many people here, you persist in your misreporting. I can
only assume that is willful.

I once again invite anyone who actually cares to look up the original
article and find out what Greenhill really said.

bob