ABSTRACT
This chapter describes the implementation of a real-time signal processing system that uses dynamic level expansion to simulate the effects of sensorineural hearing impairment for normal-hearing listeners. Several aspects of the system are characterized, including signal processing behavior and transformations of simple input signals. This characterization is directed at understanding the effect of the simulator on the stimulus configurations used in typical psychoacoustic experiments. The effects of the simulator on thresholds for tones in quiet, intensity discrimination for tones, and pure-tone psychophysical tuning curves are predicted from these characterizations. The chapter explores the implementation and evaluation of an expansion simulation of hearing impairment that functions in real time. A precise characterization of simulator operation is fundamental to understanding the results of psychophysical and speech reception tests that use dynamic expansion to simulate sensorineural hearing loss. The expansion simulator is a real-time implementation of the offline processing system studied by P. Duchnowski and R M. Zurek.
