Reproducing the Acoustic Velocity Vectors in a Spherical Listening Region

TL;DR

This paper introduces a velocity matching algorithm for reproducing acoustic velocity vectors in a spherical listening region, enabling accurate sound field reproduction over a volume rather than at discrete points, with fewer loudspeakers.

Contribution

It presents a novel velocity matching algorithm that reproduces AVVs throughout a spherical region by matching spherical harmonic coefficients derived from pressure measurements.

Findings

Accurately reproduces AVVs in the spherical listening region.

Requires fewer loudspeakers than pressure matching algorithms.

Allows listener movement beyond traditional sweet spots.

Abstract

Acoustic velocity vectors (AVVs) are related to the human's perception of sound at low frequencies and are widely used in Ambisonics. This paper proposes a spatial sound field reproduction algorithm called velocity matching, which reproduces the AVVs in the spherical listening region by matching the AVVs' spherical harmonic coefficients. Using the sound field translation formula, the spherical harmonic coefficients of the AVVs are derived from the spherical harmonic coefficients of the pressure, which can be measured by a higher-order microphone array. Unlike algorithms that only control the AVVs at discrete sweet spots, the proposed velocity matching algorithm manipulates the AVVs in the whole spherical listening region and allows the listener to move beyond the sweet spots. Simulations show the proposed velocity matching algorithm accurately reproduces the AVVs in the spherical listening region and requires fewer number of loudspeakers than pressure matching algorithm.