On Sun, 19 Sep 2004 11:34:38 +0000 (UTC), Stewart Pinkerton
wrote:

On Sun, 19 Sep 2004 07:45:08 +0000 (UTC), "Alan Murphy"
wrote:

"Stewart Pinkerton" wrote in message
. ..
On Fri, 17 Sep 2004 07:53:59 +0000 (UTC), "Alan Murphy"
wrote:

I'll bet you an even £1000 that on my system, playing my
music, I can tell the difference between a Technics CD player
SL-PG490 alone, and the same player with a Meridian DAC
203 optically connected, in more than 67% instances."
~~~~~~~~~~~
That's simple enough isn't it? What is it that you don't
understand? What is confusing you?

What I don't understand is why you're so terrified of simply setting
the volumes to the same level. Scared to admit that you wasted money
on the DAC?

Your crude and patronising approach to subtle audio
differences, offering a paltry sum of money to take part
in an A/B test that masks all but gross differences, is doing
the industry a disservice and is as distasteful as snake oil,
IMHO.

My approach is certainly not crude, it's the same method used by the
Subjective Evaluation Group at Harman International (brand names
include Mark Levinson, Madrigal and JBL, among others). ABX testing is
used because it *reveals* the most subtle differences, which are often
concealed by other methods, sighted listening being demonstrably
useless for discriminating subtle differences. That's why Harman (and
B&W, KEF etc etc) use it every day in product development. Its other
great strength is that it demonstrates the nonexistence of *imagined*
differences, such as those between cables, so that the development
engineer can check if that 'audiophile approved' component really does
make an audible difference, or if he just wanted it to.

What is 'patronising' is your presumption (with no actual proof) that
you really can hear a difference in sound *quality* between your
player and your DAC. Since you think that £1,000 is a paltry sum (even
though *you* suggested it), let's make it an even £10,000 wager.

You've read the small print and are in complete agreement?

What 'small print'? Levels are equalised to +/- 0.1dB, the test
protocol is double-blind, and you need to score more than 20 correct
out of 30 trials. That's it.


For such a small statistical population, 20 out of 30 is
extraordinarily generous, especially considering that the subject
would be claiming something very close to 100%, particularly if they
get to choose the listening material. Although in strict Chi squared
terms it is a good score, Sod's law dictates that it can happen quite
easily by chance. Having achieved the 20, it should be necessary to do
it again to show it wasn't a fluke.

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