Masking-level difference in filtered-random and amplitude-modulated noise.
The masking characteristics of filtered-random noise and amplitude-modulated noise (40-dB pressure-spectrum level) were studied in a series of four experiments using a masking-level difference paradigm, that is, 500-Hz thresholds in S0N0 and SpiN0 binaural conditions. In Experiment 1 a filtered noise (200-800 Hz) and an amplitude-modulated noise (425-575 Hz) produced equal thresholds in S0N0; for SpiN0, however, the thresholds in amplitude-modulated noise were 1.6 dB lower than were the thresholds in filtered noise. In Experiment 2 S0N0 and SpiN0 thresholds were established in three filtered noise bandwidths (200-800 Hz, 335-685 Hz, and 410-600 Hz) and in the amplitude-modulated noise (425-575 Hz). When the bandwidths of the filtered-random and amplitude-modulated noises were similar, the SpiN0 thresholds were the same but the S0N0 thresholds were different. Experiments 3 and 4 indicated that with amplitude-modulated noise when the zero amplitude crossings of the tone and the noise coincided, the S0N0, SpiN0, and SmNm thresholds were 1.2-2.0 dB higher than were the thresholds when the zero crossings of the tone and noise did not coincide. The data indicate that the masking characteristics of filtered-random noise and amplitude-modulated noise are different. The findings are interpreted as an indication that perceptual phenomena depend on the temporal characteristics as well as the power spectrum of the signal and masker.
D000328:Adult; D001301:Audiometry, Pure-Tone; D001309:Auditory Threshold; D006801:Humans; D008144:Loudness Perception; D009622:Noise; D010470:Perceptual Masking; D010898:Pitch Perception