The Masking of Pure Tones and of Speech by White Noise

Abstract

Monaural masking of pure tones by white noise at 8 sensation levels from 20 to 90 db. was measured and used to determine 2 functions: (1) the ratio, in db., between the level of a pure tone and the level per cycle of the noise that is just able to mask the tone; (2) the function relating the amt. of masking to the effective level of the masking noise. Using these functions, a set of contours was constructed representing the masked threshold for pure tones heard monaurally against a background of white noise. The masking of speech, in the form of continuous discourse, by white noise was also measured at the same 8 noise levels used to mask pure tones.