[ARSCLIST] A/B testing: another approach

[Matthew Barton <mbarton@xxxxxxx>]

Here's a link to an article from the October issue of Stereophile, in
which an interesting approach to blindfold testing is described:

http://www.stereophile.com/asweseeit/1007awsi/index.html 

This is not an analog vs. digital article, and I'm not endorsing the
test or or its results, or any conclusions in the article, but I think
the approach is interesting. Instead of an A:B comparision, in which
listeners first heard A, and then B, and were asked for opinions, this
engineer created a composite patchwork of different formats using a
repetitive passage from a recent recording of Handel's Messiah. He
didn't tell his audience that this is what they would be hearing:

"It turned out that we'd been unwittingly involved in a blind listening
test. The DVD-A was a ringer. Philip had chosen a Handel chorus in which
the same music is heard four times. He had prepared four versions of the
chorus—the original 24-bit/88.2kHz data transcoded straight from the
DSD master; a version sample-rate–converted and decimated to 16/44.1
CD data; an MP3 version at 320kbps; and, finally, an MP3 version at
192kbps—and spliced them together in that order. The last three
versions had been subsequently upsampled back to 24/88.2 so that the
DAC's performance would not be a variable. The peak and average levels
were the same for all four versions; the only difference we would hear
would be the reductions in bandwidth and resolution. "-- from "Watching
the Detectives," by John Atkinson, Stereophile, October, 2007.

We can all argue about the specs here, but the most interesting thing
to me is that the changes in the audio unfolded over four iterations of
the same passage of music in the same recording. Listeners were not
asked to use their memory of recording A to appraise recording B,or vice
versa. They heard (or did not hear) the changes as part of continuous
listening experience.


Matthew Barton
MBRS
The Library of Congress
101 Independence Ave., SE
Washington, DC 20540-4696
202-707-5508
email: mbarton@xxxxxxx