The role of envelope fluctuations in spectral masking.

Two experiments are reported in this study. In the first experiment the masking effect of five different types of narrow-band maskers was compared. The masker was either a tone, a narrow-band Gaussian noise, or a multiplication noise obtained by multiplying a sinusoid with a low-pass Gaussian noise. The noise maskers had a bandwidth of either 20 or 100 Hz. In all cases the masker had a center frequency of 1.3 kHz and a duration of 500 ms. Five-point growth-of-masking functions were measured using a 2-kHz tonal target with a duration of 400 ms, temporally centered in the masker. Six subjects participated in the experiment. Although considerable intersubject differences were observed, the data of all subjects showed several common trends. First, the tonal maskers produced more masking than the noise maskers. Second, Gaussian noise maskers produced more masking than multiplication noise maskers of the same bandwidth. Finally, 100-Hz-wide noise maskers produced more masking than 20-Hz-wide maskers of the same type. Differences in masked thresholds between the various masker types generally increased with masker level, and exceeded 25 dB in some conditions. The results are discussed in terms of masker envelope fluctuations. In the second experiment the masking effect was investigated for a bandpass noise at 1.3 kHz, with regular zero crossings, but with the envelope characteristics of a 100-Hz-wide Gaussian noise. Five-point growth-of-masking functions were measured using a tonal target of 2 kHz.(ABSTRACT TRUNCATED AT 250 WORDS)

[1]  Brian R Glasberg,et al.  Derivation of auditory filter shapes from notched-noise data , 1990, Hearing Research.

[2]  P. O. Thompson,et al.  The Frequency Selectivity of the Ear as Determined by Masking Experiments , 1950 .

[3]  L. Humes,et al.  Models of the additivity of masking. , 1989, The Journal of the Acoustical Society of America.

[4]  Hugo Fastl.  Loudness and masking patterns of narrow noise bands , 1975 .

[5]  B C Moore.  Additivity of simultaneous masking, revisited. , 1985, The Journal of the Acoustical Society of America.

[6]  H. Levitt.  Transformed up-down methods in psychoacoustics. , 1971, The Journal of the Acoustical Society of America.

[7]  Armin Kohlrausch,et al.  Using an excitation-pattern model to predict auditory masking , 1994, Hearing Research.

[8]  L. Feth,et al.  Effects of the Temporal Properties of a Masker upon Simultaneous-Masking Patterns , 1986 .

[9]  W M Hartmann,et al.  Noise power fluctuations and the masking of sine signals. , 1988, The Journal of the Acoustical Society of America.

[10]  Lidia W. Lee,et al.  Two experiments on the spectral boundary conditions for nonlinear additivity of simultaneous masking. , 1992, The Journal of the Acoustical Society of America.

[11]  R. L. Wegel,et al.  The Auditory Masking of One Pure Tone by Another and its Probable Relation to the Dynamics of the Inner Ear , 1924 .

[12]  S Buus,et al.  Release from masking caused by envelope fluctuations. , 1985, The Journal of the Acoustical Society of America.

[13]  R A Lutfi,et al.  Additivity of simultaneous masking. , 1983, The Journal of the Acoustical Society of America.

[14]  R. Patterson.  Auditory filter shape. , 1974, The Journal of the Acoustical Society of America.

[15]  H. Hake,et al.  On the Masking Pattern of a Simple Auditory Stimulus , 1950 .

[16]  D. M. Green,et al.  Signal detection theory and psychophysics , 1966 .

[17]  E. de Boer,et al.  Masking and Discrimination , 1966 .

[18]  S. S. Stevens.  Frequency Analysis and Periodicity Detection in Hearing. , 1972 .

[19]  B C Moore,et al.  Factors affecting thresholds for sinusoidal signals in narrow-band maskers with fluctuating envelopes. , 1987, The Journal of the Acoustical Society of America.

[20]  W. Jesteadt,et al.  Psychophysical tuning curves in normal-hearing listeners: test reliability and probe level effects. , 1984, Journal of speech and hearing research.