Effect of high-density additional rippled patterns on ripple density resolution thresholds

Abstract

This study aims to spot an effect of the density of an additional rippled signal on ripple density resolution thresholds when this density is greatly exceeding the density of the main signal. In such a case a spectrum is formed from two harmonic functions. Therefore, a phase-reversed spectral ripple resolution test was used in this research, which includes two experimental paradigms. In both 2 oct narrowband white noise passes through pre-made filters. A ripple density of the additional signal was varied from 10 to 50 ripples/oct. In a rippled test and reference stimuli the mean resolution was 9 ripples/oct. This fact supports the involvement of cochlear excitation patterns for the discrimination of such signals. In a test with the stimuli with an additional rippled signal and non-rippled reference signal the thresholds cannot be reduced to mean value. However, the ripple density resolution thresholds for 20, 30, and 50 ripple densities of additional signal gravitate towards the value of 11,25 ripples/oct. The ripple density resolution thresholds for 10 and 15 ripples/oct are higher than the other values what suggests a special combination of spectral and temporal mechanisms.