Modulation masking produced by second-order modulators

Recent studies suggest that an auditory nonlinearity converts second-order sinusoidal amplitude modulation (SAM) (i.e., modulation of SAM depth) into a first-order SAM component, which contributes to the perception of second-order SAM. However, conversion may also occur in other ways such as cochlear filtering. The present experiments explored the source of the first-order SAM component by investigating the ability to detect a 5-Hz, first-order SAM probe in the presence of a second-order SAM masker beating at the probe frequency. Detection performance was measured as a function of masker-carrier modulation frequency, phase relationship between the probe and masker modulator, and probe modulation depth. In experiment 1, the carrier was a 5-kHz sinusoid presented either alone or within a notched-noise masker in order to restrict off-frequency listening. In experiment 2, the carrier was a white noise. The data obtained in both carrier conditions are consistent with the existence of a modulation distortion component. However, the phase yielding poorest detection performance varied across experimental conditions between 0° and 180°, confirming that, in addition to nonlinear mechanisms, cochlear filtering and off-frequency listening play a role in second-order SAM perception. The estimated magnitude of the modulation distortion component ranges from 5%-12%

Familiar Environmental Sound Test - Matlab package

<p>This zip file includes Matlab routines to administer Familiar Environmental Sound Test (FEST).  It also contains FEST stimuli.  </p

Discrimination of Static and Dynamic Spectral Patterns by Children and Young Adults in Relationship to Speech Perception in Noise

Past work has shown relationship between the ability to discriminate spectral patterns and measures of speech intelligibility. The purpose of this study was to investigate the ability of both children and young adults to discriminate static and dynamic spectral patterns, comparing performance between the two groups and evaluating within- group results in terms of relationship to speech-in-noise perception. Data were collected from normal-hearing children (age range: 5.4-12.8 years) and young adults (mean age: 22.8 years) on two spectral discrimination tasks and speech-in-noise perception. The first discrimination task, involving static spectral profiles, measured the ability to detect a change in the phase of a low-density sinusoidal spectral ripple of wideband noise. Using dynamic spectral patterns, the second task determined the signal-to-noise ratio needed to discriminate the temporal pattern of frequency fluctuation imposed by stochastic lowrate frequency modulation (FM). Children performed significantly poorer than young adults on both discrimination tasks. For children, a significant correlation between speech-in-noise perception and spectral- pattern discrimination was obtained only with the dynamic patterns of the FM condition, with partial correlation suggesting that factors related to the children’s age mediated the relationship