Factors affecting frequency discrimination in high‐ and low‐pass noise backgrounds

Abstract

Previously, we presented data which indicated that frequency discrimination performance was poorer for tones presented near the spectral edge of a low‐pass noise than for tones presented either near the edge of a high‐pass noise or in an unfiltered white noise background. [D. S. Emmerich, D. A. Fantini, and W. S. Brown, J. Acoust. Soc. Am. Suppl. 1 74, S34 (1983)]. The present study extends these findings in order to investigate how the steepness of the spectral edges of low‐ and high‐pass maskers influences the discriminability of tones presented near these edges. Frequency separations corresponding to 75% correct responses were obtained in each of three low‐ and three high‐pass noise backgrounds differing in the steepness of their filter skirts. The following results were obtained: (1) in the low‐pass noise background, frequency discrimination performance improved as the filter skirt became more gradual, even though more noise power was added; (2) in the high‐pass noise background, performance first improved and then became poorer as the filter skirt became shallower; (3) performance in low‐pass noise was poorer than that in high‐pass noise for the two steepest slopes employed (96 and 72 dB/oct) and better for the shallowest slope (36 dB/oct). Results are discussed in the context of a trade‐off between possible edge effects and masking.