On Wed, 11 Jan 2006 10:50:25 -0500, "Arny Krueger"
wrote:


"Don Pearce" wrote in message
...
OK, I've had a bit of a think - and I've written a protocol, which I
believe would be a basis of fair testing of audio components to
resolve such issues as cable sound etc.

I invite all here to read what I suggest, and let me know if I have
either missed something, or am being unfair on one direction or
another.

http://www.donepearce.plus.com/odds/dbt/

I think this could be a way of defusing the vituperation that
currently surrounds the subject.

So what do you think?

Just cruising through quickly...

(1) We always level-matched at 20 and 20 KHz, as well as several places
in-between. Its not hard to hear a roll-off below 100 Hz. Also there is the
possibility of notches in the frequencies in-between.

OK - not necessary for cables, though. Maybe I could shift the 15kHz
tone up to 20kHz, but I suspect there may be some CD players that
aren't totally flat up there.

(2) Note the elaborate listener training that is available at www.pcabx.com
. It's there for a reason. ;-)

This protocol is to test subjects who have already identified a
difference, so no listener training is required.

(3) Time-synching does not seem to be mentioned. If this protocol is only
for cables, its unlikely to be needed.

That's right This isn't a protocol for fast ABX switching, so there is
no need. Indeed the test would allow the subject to start and stop the
music, swap CDs etc - whatever he wants really, to aid his decision.

(4) The person who connects the cables does not seem to be fully concealed
from the listener, thus the test is arguably not double blind. Some say that
body language is the truly universal language.

The cable changer should be concealed from test start to finish. He should
do what he does base on non-interactive voice commands from the listening
room.

The cable changer is a skeptic, so should be able to do his job
without communicating any info. In the case of interconnects, I
suppose both bits of kit could be in another room, but not for speaker
cables. I think the protocol is secure enough for practical purposes.
The main thing is to keep the observer from communicating with the
subject. I have made a change to reflect this in an updated page

(5) IMO 16/16 is a bit severe. 14/16 is good enough for me.


It is 16/20, followed by a further 16/20 if successful the first time.

d

Pearce Consulting
http://www.pearce.uk.com