Stewart, et, the wire test pot gang.

Im sorry if these questions have already been answered, but the
previous set of threads became so long and nauseous even my news
server couldn't cope and dropped a large number of them, such that I
was not able to conclude answers to the questions below.

As a requirement of the test you need to level match the response the
cables at 3 points (100Hz 1KHz and 10KHz) Yes ?.
How would this done ? assuming that there is a response mismatch of
say 3db between the 100Hz and 10KHz between the cables under test.

Is the levelling of the responses a voltage/power drive to the
speakers in the test ?
or is it to the spl at 1 or 2 metres from the loudspeaker ?

On Sun, 18 Jan 2004 02:37:59 GMT, "chris"
wrote:

Stewart, et, the wire test pot gang.

Im sorry if these questions have already been answered, but the
previous set of threads became so long and nauseous even my news
server couldn't cope and dropped a large number of them, such that I
was not able to conclude answers to the questions below.

As a requirement of the test you need to level match the response the
cables at 3 points (100Hz 1KHz and 10KHz) Yes ?

Yes.

How would this done ? assuming that there is a response mismatch of
say 3db between the 100Hz and 10KHz between the cables under test.

The bass response will in my experience never be affected by rective
components, so the 100Hz and 1kHz levels would be matched by the
addition of a small resistor (or simply by using a higher gauge of
'zipcord'), while any deliberate treble droop in the 'boutique' cable
would be matched by the addition of a small inductor in series with
the zipcord. I believe it unlikely that any adjustment would ever be
required for ultra-low inductance cables, as zipcord has reasonably
low inductance.

As noted elsewhere, the real purpose of the level-matching requirement
is to prevent cheating by someone introducing a specially-built cable
with truly bizarre electrical characteristics.

Is the levelling of the responses a voltage/power drive to the speakers in the test ?
or is it to the spl at 1 or 2 metres from the loudspeaker ?

As has been clearly specified many times, it is the voltage at the
speaker terminals which is level-matched.
--

Stewart Pinkerton | Music is Art - Audio is Engineering

"Buster Mudd" wrote in message
news:FMePb.107785$xy6.268175@attbi_s02...
"Bob Marcus" wrote in message
...
I would welcome a directive from the moderators on how
to discuss
the "4k challenge" without discussing the method selected for it-
namely
ABX/DBT.
Ludovic Mirabel

[ Moderator's note: As long as the discussion sticks to the
details
of the challenge, i.e., what are the requirements for performing
the
tests and what is the criteria for winning, without discussing
whether
or not ABX/DBT works or is a good idea, and it meets all the
guidelines, it will be accepted. -- deb ]

I can't speak for others, but I wouldn't insist on ABX. I'd
consider other
possible double-blind forced-choice tests, such as a
same-different test or
even an A-B preference test, if our contestant were more
comfortable with
one of those.


It always struck me that a double-blind same-difference would be
enough to convince both sides of the issue...assuming that the issue
is "You Can/Can't Hear A Difference Between Cables". (Though as
noted
in recent posts, I may have been wrong about that fundamental
premise!)

Requiring a test subject identify whether 1 of 2 possible cables is
A
or B (i.e., the now verbotten AyBeeEx test) is a wonderful way of
determining the degree of the test subject's discriminatory
abilities.
But it is unnecessarily rigorous if one is simply trying to
determine
whether or not that test subject's discriminatory abilities are
refined enough to identify that a difference exists.

I actually wonder if any one could tell the difference between the
"audiophile cable" and the doctored zip cord in SIGHTED tests without
any DBT's ?

So I would guess the cable pot gang will keep their money.

On Fri, 23 Jan 2004 23:43:50 GMT, "chris"
wrote:

I actually wonder if any one could tell the difference between the
"audiophile cable" and the doctored zip cord in SIGHTED tests without
any DBT's ?

Sure you can, in fact I'll happily demonstrate 'obvious' audible
differences to you in a sighted test, when I haven't actually changed
anything!

BTW, in over a dozen tests I've performed so far, I've never had to
'doctor' the zipcord, adequate level matching has always been achieved
with the cables 'straight out of the box', so Buster Mudd's subthread
is something of a red herring.

So I would guess the cable pot gang will keep their money.

I would guess so too, but not for the reason you cite! :-)
--

Stewart Pinkerton | Music is Art - Audio is Engineering