Double blind testing is usually a humbling experience. Having participated in a number of such tests over the years and dealing with double blind testing in other scientific fields, I can unequivically state that the results with auditory tests involving electronic components are usually unrevealing and that differences can easily be obscured rather than highlighted.

One such test involved comparing two CD players in the 1988. One of the players had a patently defective DAC that truncated the data to about ten bits. Listening to the player at home induced a pounding headache after two or three tracks of just about any disc that I tried. Gritty, grainy, hashy, noisy, and "electronic" are all terms that could be used to describe the sound eminating from that forlorn component.

Several musical selections were chosen for the test and included both classical orchestral material and a pop track. The playback system was of high quality and both players produced nearly the same output voltage, so no complicated level matching was necessary. Four experienced audiophiles were involved, and each listener could take as long as needed for the tests. Only two of us could consistently identify the defective player. I had the advantage of knowing what to listen for, but passed only on the classical selection. No one could pass with the pop music despite repeated attempts. Following the conclusion of the test, I sent the defective player home with one of those that couldn't pass with either program. That next day he called and explained that the CD player must have been damaged in transport to his apartment, because it sounded terrible! The moral of the story - be very careful when interpreting data from this type of auditory test.