Tinnitus and Zwicker tone may be produced by simple gain adaptation.

Listen to:
Audio re-synthesized from original powers
Audio re-synthesized from gain-adjusted powers

Zwicker tone: Here is some matlab code (zwicker.m) that will play band-gap noise, which should elicit a Zwicker tone in some subjects (assuming you have got the right hardware). Our data shows that about 1/3 of normal subjects will hear the Zwicker tone for at least one of the three band-gaps presented here. Subjects that report tinnitus are just about guaranteed to hear a Zwicker tone. This is a sound file with three examples of notched noise that may elicit a Zwicker tone followed by a forth white noise which should not.

Beware of the hardware: Most inexpensive sound cards on a PC or laptop and many headphones will not be able to reproduce a sharp and deep notch as required. We used MAYA44 as sound card and Sony MDR-7506 headphones. We whiten the noise spectrum of the headphones using calibrated microphones to ensure uniform SPL across frequencies. Any 24 bit sound card should be fine. These Sony headphones are nice because they really don't seem to inject any noise in the band-gap.

Lucas C. Parra, Barak A. Pearlmutter, "Illusory percepts from auditory adaptation", Journal of the Acoustical Society of America, accepted for publication November 20, 2006.

Lucas Parra, Dec 12, 2006, updated Jun 9, 2008