Analysis on decorrelation effect of audio signal in multichannel reproduction

Abstract

Decorrelation of audio signal is a process that generates two or more incoherent signals from a single input signal, which has many applications in artificial auditory effects, such as broadening the apparent source width (ASW), enhancing the subjective envelopment, producing subjective diffusion in multichannel reproduction, etc. Frequently used decorrelation method is convoluting audio signal with random (or pseudo-random) noise. In this work, we focus on the relationship of reproduction zone of multichannel reproduction with decorrelation degree. Simulation calculation result show that, by changing the decorrelation degree which is measured by the interaural cross-correlation coefficients (IACC) of reproduced signals, the timbre will change when move off the listening center. Listening zone with small timbre deviation (for example, binaural loudness spectra less than 1dB/ERB) relative to center position increase with the value of IACC decrease. But as well known, for good subjective diffusion, the least IACC value does not mean the best effect. There exit a best IACC value range from 0.2~0.4 for different audio signal. Adapting a best IACC value, a reproduction zone across different frequencies can be achieved.