Localization Uncertainty in Time-Amplitude Stereophonic Reproduction

TL;DR

This paper presents a computational model to quantify localization uncertainty in stereophonic sound reproduction, validated by listening tests, and compares amplitude and time-amplitude methods for different listener positions.

Contribution

It introduces a novel model for localization uncertainty based on inter-aural cues and validates it with high correlation, providing insights into stereo setup optimization.

Findings

Amplitude methods perform better at the center of the stereo image.

Time-amplitude methods outperform when the listener moves away from the center.

The model accurately predicts localization uncertainty with a Pearson correlation of 0.99.

Abstract

This article studies the effects of inter-channel time and level differences in stereophonic reproduction on perceived localization uncertainty, which is defined as how difficult it is for a listener to tell where a sound source is located. Towards this end, a computational model of localization uncertainty is proposed first. The model calculates inter-aural time and level difference cues, and compares them to those associated to free-field point-like sources. The comparison is carried out using a particular distance functional that replicates the increased uncertainty observed experimentally with inconsistent inter-aural time and level difference cues. The model is validated by formal listening tests, achieving a Pearson correlation of 0.99. The model is then used to predict localization uncertainty for stereophonic setups and a listener in central and off-central positions. Results show that amplitude methods achieve a slightly lower localization uncertainty for a listener positioned exactly in the center of the sweet spot. As soon as the listener moves away from that position, the situation reverses, with time-amplitude methods achieving a lower localization uncertainty.