Off-frequency listening and masker uncertainty.
This experiment was designed to determine if masker uncertainty can reduce the effects of off-frequency listening on psychophysical tuning curves (PTCs). PTCs were determined in simultaneous masking with a 1-kHZ signal at 12 dV SPL, using an adaptive two-alternative forced-choice procedure. In a given run the center frequency on the narrow-band noise masker was either fixed, or varied randomly between up to eight values distributed equally above and below the signal frequency. In a control condition off-frequency listening was restricted using a "notched" broadband noise added to fixed-frequency masker. The notch was 200 HZ wide, centered at the signal frequency, and the spectrum level in the passband was - 8 dB SPL/Hz. The "restricted listening" PTCs were considerably broader than the "traditional" PTCs, but uncertainty about masker frequency had little effect. It appears that prior knowledge of masker frequency is not necessary for off-frequency listening to be effective.
D001309:Auditory Threshold; D006801:Humans; D010470:Perceptual Masking; D011571:Psychoacoustics