Sensitivity to ITD changes in a binaural detection model

In this contribution, we analyze the binaural model, proposed by Breebaart, van de Par and Kohlrausch in 2001, for its ability to predict just noticeable differences in interaural time differences (ITDs). This model is conceptually similar to crosscorrelation models, and the relevant model property for ITD detection is its internal delay line. We first study, which point along the internal delay axis changes most when the ITD of a sinusoidal stimulus changes. There are two candidate positions: First, the position where the crosscorrelation function of the reference stimulus has its maximum (e.g., zero ms for a stimulus without any ITD), and secondly a point at which the crosscorrelation function has its steepest slope, which is at a delay corresponding to a quarter period of the stimulus. With this analysis, we can also compare the model’s thresholds depending on the considered positions. A second question of interest is how the model deals with stimulus randomness in ITD experiments. From perception experiments it is known that the thresholds for sinusoidal stimuli and for narrowband random-noise stimuli with the same center frequency are very close