Trumpai, radau įdomios medžaigos (pateikiu tekstą žemiau, anglų kalba), 
apie aklus testus iš grynai Pro srities - Švedijos radijo perėjimas prie 
kitų standartų/kodekų.

Esminis dalykas - 20.000 aklų testų ir 60 PRO ekspertų nesugebėjo 
PASTEBĖTI techninio kodeko artefakto 1.5kHz dažnyje , kurį per 10 min 
pastebėjo VIENINTELIS audiofilas, PIRMOJE perklausoje.

KODĖL?

Istorija:

	Most such tests, including this new CD vs. high-res comparison, are 
performed not by disinterested experimenters on a quest for the truth 
but by partisan hacks on a mission to discredit audiophiles. But blind 
listening tests lead to the wrong conclusions even when the 
experimenters’ motives are pure. A good example is the listening tests 
conducted by Swedish Radio (analogous to the BBC) to decide whether one 
of the low-bit-rate codecs under consideration by the European Broadcast 
Union was good enough to replace FM broadcasting in Europe.

Swedish Radio developed an elaborate listening methodology called 
“double-blind, triple-stimulus, hidden-reference.” A “subject” 
(listener) would hear three “objects” (musical presentations); 
presentation A was always the unprocessed signal, with the listener 
required to identify if presentation B or C had been processed through 
the codec.

The test involved 60 “expert” listeners spanning 20,000 evaluations over 
a period of two years. Swedish Radio announced in 1991 that it had 
narrowed the field to two codecs, and that “both codecs have now reached 
a level of performance where they fulfill the EBU requirements for a 
distribution codec.” In other words, Swedish Radio said the codec was 
good enough to replace analog FM broadcasts in Europe. This decision was 
based on data gathered during the 20,000 “double-blind, triple-stimulus, 
hidden-reference” listening trials. (The listening-test methodology and 
statistical analysis are documented in detail in “Subjective Assessments 
on Low Bit-Rate Audio Codecs,” by C. Grewin and T. Rydén, published in 
the proceedings of the 10th International Audio Engineering Society 
Conference, “Images of Audio.”)

After announcing its decision, Swedish Radio sent a tape of music 
processed by the selected codec to the late Bart Locanthi, an 
acknowledged expert in digital audio and chairman of an ad hoc committee 
formed to independently evaluate low-bit rate codecs. Using the same 
non-blind observational-listening techniques that audiophiles routinely 
use to evaluate sound quality, Locanthi instantly identified an artifact 
of the codec. After Locanthi informed Swedish Radio of the artifact (an 
idle tone at 1.5kHz), listeners at Swedish Radio also instantly heard 
the distortion. (Locanthi’s account of the episode is documented in an 
audio recording played at workshop on low-bit-rate codecs at the 91st 
AES convention.)

How is it possible that a single listener, using non-blind observational 
listening techniques, was able to discover—in less than ten minutes—a 
distortion that escaped the scrutiny of 60 expert listeners, 20,000 
trials conducted over a two-year period, and elaborate “double-blind, 
triple-stimulus, hidden-reference” methodology, and sophisticated 
statistical analysis?

The answer is that blind listening tests fundamentally distort the 
listening process and are worthless in determining the audibility of a 
certain phenomenon.

Šaltinis:
http://www.avguide.com/forums/blind-listening-tests-are-flawed-editorial?page=1