Stereo Reproduction in the Presence of Sample Rate Offsets

TL;DR

This paper addresses the challenge of clock skew caused by sample rate offsets in wirelessly connected loudspeakers, proposing an audio-domain compensation method that improves spatial audio reproduction by mitigating perceptual degradation.

Contribution

It introduces a novel spatial filtering-based SRO compensation technique that estimates and corrects sample rate offsets before spatial audio rendering.

Findings

The proposed method effectively reduces perceptual degradation in spatial audio.

Subjective listening tests show improved spatial cue preservation.

Objective metrics confirm the effectiveness of the compensation approach.

Abstract

One of the main challenges in synchronizing wirelessly connected loudspeakers for spatial audio reproduction is clock skew. Clock skew arises from sample rate offsets ( SROs) between the loudspeakers, caused by the use of independent device clocks. While network-based protocols like Precision Time Protocol (PTP) and Network Time Protocol (NTP) are explored, the impact of SROs on spatial audio reproduction and its perceptual consequences remains underexplored. We propose an audio-domain SRO compensation method using spatial filtering to isolate loudspeaker contributions. These filtered signals, along with the original playback signal, are used to estimate the SROs, and their influence is compensated for prior to spatial audio reproduction. We evaluate the effect of the compensation method in a subjective listening test. The results of these tests as well as objective metrics demonstrate that the proposed method mitigates the perceptual degradation introduced by SROs by preserving the spatial cues.