Some Masking Effects Produced by Low-Frequency Vowel Formants in Persons with Sensorineural Hearing Loss

Abstract

Discrimination of second-formant (F2) transitions in synthetic vowels was measured with and without the first formant (F1) present, with F1 and F2 presented monotically vs dichotically, and with the onset of F1 delayed relative to the onset of F2. Twenty-three subjects with sensorineural loss were tested. When F2 was presented alone, discrimination thresholds were the same as those of normal-hearing subjects. In most sensorineural subjects, discrimination was reduced whenever F1 was present in the stimulus. F1 produced three types of masking that reduced the ability to discriminate F2 transitions: upward spread of masking and backward masking occurred when F1 and F2 were presented to the same ear; a type of central masking occurred when F1 and F2 were presented to opposite ears.