The far-field equatorial array for binaural rendering

We present a method for obtaining a spherical harmonic representation of a sound field based on a microphone array along the equator of a rigid spherical scatterer. The two-dimensional plane wave decomposition of the incoming sound field is computed from the microphone signals. The influence of the scatterer is removed under the assumption of distant sound sources, and the result is converted to a spherical harmonic (SH) representation, which in turn can be rendered binaurally. The approach requires an order of magnitude fewer microphones compared to conventional spherical arrays that operate at the same SH order at the expense of not being able to accurately represent non-horizontally-propagating sound fields. Although the scattering removal is not perfect at high frequencies at low harmonic orders, numerical evaluation demonstrates the effectiveness of the approach.