Parametric Ambisonic Encoding of Arbitrary Microphone Arrays

Sound samples (.wav), CAD models (.stl), COMSOL model (.mph) and array response simulations (.mat) used to evaluate methods presented in the paper: Parametric Ambisonic Encoding of Arbitrary Microphone Arrays

Abstract

This article proposes a parametric signal-dependent method for the task of encoding microphone array signals into Ambisonic signals. 
The proposed method is presented and evaluated in the context of encoding a simulated seven-sensor microphone array, which is mounted on an augmented reality headset device. Given the inherent flexibility of the Ambisonics format, and its popularity within the context of such devices, this array configuration represents a potential future use case for Ambisonic recording. However, due to its irregular geometry and non-uniform sensor placement, conventional linear Ambisonic encoding is particularly limited. The primary aims of the proposed method are to obtain Ambisonic signals over a wider frequency band-width, and at a higher spatial resolution, than would otherwise be possible through conventional linear encoding. The proposed method is based on a multi-source sound-field model and employs spatial filtering to divide the captured sound-field into its individual source and directional ambient components, which are subsequently encoded into the Ambisonics format at an arbitrary order. It is demonstrated through both objective and subjective evaluations that the proposed parametric method outperforms conventional linear encoding in the majority of cases.