Interaural fluctuations and the detection of interaural incoherence. IV. The effect of compression on stimulus statistics.

The purpose of this experiment was to determine whether the normalized interaural cross-correlation (CC) model or a model based on interaural phase and level differences can better describe incoherence detection data. The ability to detect interaural incoherence in three sets of reproducible dichotic noises was tested in six listeners. The first set contained noises with a constrained value of the CC and the CC including signal compression. The second set contained noises with a constrained value of the CC including signal compression. The third set contained noises with constrained values in the fluctuations in the interaural differences. Modeling showed that neither the CC model nor the model using the interaural differences could account for the data in any set. Examination of the statistical properties of the stimuli showed that including compression before the calculation of the interaural CC causes a substantial correlation of this metric to the fluctuations in the interaural phase difference. This finding implies that it may be more difficult to discriminate between the common types of binaural models than previously thought.