Modelling the frequency dependency of binaural masking level difference and its role for binaural unmasking of speech in normal hearing and hearing impaired listeners

Abstract

In binaural tone-in-noise detection experiments humans can achieve substantially lower thresholds if either noise or tone have interaural time or phase differences (ITDs / IPDs) compared to diotic presentation of tone and noise. This effect is named binaural masking level difference (BMLD) and was mainly investigated at 500 Hz. The results obtained in these experiments were used to fit binaural processing errors in the equalization-cancelation (EC) mechanism, which is an effective model of binaural processing. In this study, the frequency dependency of BMLDs is investigated for listeners with normal hearing and high frequency hearing loss. Binaural tone-in-noise detection experiments are conducted for tone frequencies of 250, 500, 750, 1000, 1500, and 2000 Hz, and ITDs of the noise up to 5 times the period of the tested frequency. Furthermore, diotic and dichotic speech reception thresholds for low pass filtered speech in noise are measured with the same listeners. The EC mechanism with processing errors ...