Monaural envelope correlation perception

The ability to discriminate between simultaneously presented 100-Hz-wide bands of noise with envelopes that were either similar or dissimilar was measured. The center frequencies of the noise bands, fL and fL + delta f Hz, were systematically varied. When the bands of noise were separated by an octave, delta f = fL, discriminations were at chance levels. For frequency separations less than an octave, delta f less than fL, discrimination was best for fL = 2500 and 4000 Hz, somewhat poorer for fL = 1000 Hz, and impossible for fL = 350 Hz. Listeners were also asked to discriminate between bands of noise with envelopes that were either perfectly or partially correlated, and bands with envelopes that were either uncorrelated or partially correlated. The data suggest that, when transformed to an equal-variance scale (Fisher's z), equal changes in Fisher's z lead to equal changes in detectability, regardless of the correlation of the envelopes of the reference signal.