Gliding ripple speed thresholds for rippled spectra

Abstract

Rippled noise is a productive model of natural signals with complex spectrum patterns. It was used as a test signal to measure spectrum-pattern resolution both in normal-hearing listeners and in hearing-impaired listeners and users of cochlear implants. However, a variety of natural auditory signals feature combined spectro-temporal patterns. These signals may be modeled by rippled noise with ripples. In the present study, ripple gliding speed thresholds were measured in normal-hearing listeners. The highest gliding speed (expressed in oct/s or ripples/s) at which the gliding ripple pattern could be distinguished from a non-rippled noise was determined. The ripple gliding speed threshold expressed in ripple/s was inversely-proportional to the ripple density (ripples per octave, RPO); it decreased from approximately 400–500 ripple/s at RPO of 1/oct to approximately 50 ripple/s at RPO of 10/oct. Expressed in oct/s, the threshold decreased from 400 to 500 oct/s at RPO of 1/oct to 5 oct/s at RPO of 10/oct. Thus, the ripples fused into non-rippled spectrum at gliding speed more than 400 to 500 Hz/oct. At this speed, 400 to 500 ripples per second glide through an octave frequency band. [Work supported by The Russian Science Foundation, Grant 16-15-10046.]Rippled noise is a productive model of natural signals with complex spectrum patterns. It was used as a test signal to measure spectrum-pattern resolution both in normal-hearing listeners and in hearing-impaired listeners and users of cochlear implants. However, a variety of natural auditory signals feature combined spectro-temporal patterns. These signals may be modeled by rippled noise with ripples. In the present study, ripple gliding speed thresholds were measured in normal-hearing listeners. The highest gliding speed (expressed in oct/s or ripples/s) at which the gliding ripple pattern could be distinguished from a non-rippled noise was determined. The ripple gliding speed threshold expressed in ripple/s was inversely-proportional to the ripple density (ripples per octave, RPO); it decreased from approximately 400–500 ripple/s at RPO of 1/oct to approximately 50 ripple/s at RPO of 10/oct. Expressed in oct/s, the threshold decreased from 400 to 500 oct/s at RPO of 1/oct to 5 oct/s at RPO of ...