MASKING BY TONES VS NOISE BANDS
NAVAL MEDICAL RESEARCH LAB NEW LONDON CT
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In a previous study it was proposed that tonal masking arose mainly from the cochlear activity pattern of the masking tone, modified by the formation of beats between the signal and masking tones. The present study casts further light on these proposed mechanisms by comparing the masking effects of pure tones of 500, 1000, 2000, and 4000 cps at 60 and 80 db SL with 13 octave bands of noise of equal intensities and centered at the same frequencies. The results show that the noise bands produce about the same amount of extended masking despite the absence of any possible aural harmonic distortion, but greater direct masking due to the elimination of beats. Furthermore, the noise-masking curves join the tone-masking curves at the second peak in the latter, providing strong additional support for the proposed mechanisms of auditory masking.