Delay-Performance Tradeoffs in Causal Microphone Array Processing

TL;DR

This paper investigates the fundamental tradeoff between processing delay and noise reduction performance in real-time microphone array systems, providing exact analytical expressions and experimental validation.

Contribution

It offers the first exact delay-error expressions for causal multichannel Wiener filters and analyzes how spatial and temporal correlations influence this tradeoff.

Findings

Delay-performance curves depend on signal correlations.

Exact expressions are derived for specific cases.

Experimental results validate theoretical predictions.

Abstract

In real-time listening enhancement applications, such as hearing aid signal processing, sounds must be processed with no more than a few milliseconds of delay to sound natural to the listener. Listening devices can achieve better performance with lower delay by using microphone arrays to filter acoustic signals in both space and time. Here, we analyze the tradeoff between delay and squared-error performance of causal multichannel Wiener filters for microphone array noise reduction. We compute exact expressions for the delay-error curves in two special cases and present experimental results from real-world microphone array recordings. We find that delay-performance characteristics are determined by both the spatial and temporal correlation structures of the signals.