Audio signal processor and generator

A method of generating an audio signal, comprising:

• determining a plane-wave transfer function for a spatial-audio recording device comprising a plurality of microphones based on a physical shape of the spatial-audio recording device;
• expanding the plane-wave transfer function to generate a spherical-harmonics transfer function corresponding to the plane-wave transfer function;
• retrieving a plurality of signals captured by the microphones;
• determining spherical-harmonics coefficients based on the plurality of captured signals and the spherical-harmonics transfer function;
• and
• generating an audio signal based on the determined spherical-harmonics coefficients.

A spatial-audio recording device comprising:

• a plurality of microphones;
• and
• a computing device configured to:
• determine a plane-wave transfer function for the spatial-audio recording device based on a physical shape of the spatial-audio recording device;
• expand the plane-wave transfer function to generate a spherical-harmonics transfer function corresponding to the plane-wave transfer function;
• retrieve a plurality of signals captured by the microphones;
• determine spherical-harmonics coefficients based on the plurality of captured signals and the spherical-harmonics transfer function;
• convert the spherical-harmonics coefficients to ambisonics coefficients;
• and
• generate an audio signal based on the ambisonics coefficients.