Masking-Level Differences as a Function of Interaural Disparities in Intensity of Signal and of Noise

Abstract

A marked release from masking, or masking-level difference (MLD), results when a sinusoid is presented monaurally Sm rather than binaurally and in phase S0 with correlated (in phase) noise N0. If the sinusoid in one ear, rather than being removed entirely, is reduced in intensity relative to that in the other, a smaller MLD should result. MLD's were determined as a function of the ratio of the energies of the right- and left-ear sinusoids. This signal (500 cps, 0.25 sec) was presented in one or the other of two temporal intervals against a background of white noise N0. Also, MLD's result when Nm-Sm is changed to N0-Sm. Thus, MLD's were determined as a function of the relative intensity of the noise in the nonsignal ear with noise correlations of N0, Nπ, and NU. For N0, there is some release from masking even when the noise in the nonsignal ear is as much as 40 dB down from that in the signal ear. [Work supported by the U. S. Air Force Office of Scientific Research.]