DURATION SENSATION OF THE SIMULATED ENVIRONMENTAL NOISE IN RELATION TO ITS AUTO-CORRELATION FUNCTION

This is the report of an investigation into the sensation of the duration of environmental noise simulated by mixing a pure tone (1 kHz) with white noise. In paired-comparison tests five subjects judged whether simulated-environmental-noise stimuli were longer or shorter than a standard pure-tone stimulus with the same sound pressure level and rise–fall time. In experiment 1, the attenuation level (φm) of the envelope of the normalized auto-correlation function (ACF), i.e., the repetition of similar features in the stimulus, was varied by changing the relative amplitude of the pure tone and white-noise components. Results show that the sensation of duration of the white-noise stimulus with a small value of φmis significantly (p<0·05) longer than a pure-tone stimulus with a higher value of φm. Results of experiment 2 showed that the duration of pure-tone stimuli with lower frequencies as presented by the τ1extracted from the ACF are perceived as being longer (p<0·01) than those of pure-tone stimuli with higher frequencies.