ASA 124th Meeting New Orleans 1992 October

4pPPa18. Intensity resolution performance and loudness growth in high-pass noise.

Robert S. Schlauch

Dept. of Commun. Disord., Univ. of Minnesota, 115 Shevlin Hall, Minneapolis, MN 55455

Several models predict tight coupling between loudness growth and intensity resolution performance. To examine further the link between these measures, intensity resolution performance and loudness growth for a 1000-Hz tone were measured in the presence of a unilateral, continuous, high-pass noise (cutoff: 1800 Hz). Thresholds for the three subjects were minimally effected at the test frequency; however, for frequencies in the noise passband, thresholds were shifted to roughly 60 dB SPL. Intensity resolution was measured for gated and continuous standards using a 3-AFC procedure. Loudness matches were obtained using the contralateral ear as a reference. Below roughly 40 dB SPL, loudness growth and intensity resolution were unaltered by the presence of the noise; above 40 dB SPL, intensity resolution performance was well described by Weber's law (gated standard) or by a slight deterioration in performance (continuous standard) while loudness growth became slower. The results will be described in terms of current models for relating these measures.