Audio systems and methods for voice activity detection

An audio system comprising:

• a plurality of microphones;
• and
• a controller coupled to the plurality of microphones and configured to:
• receive a plurality of microphone signals from the plurality of microphones,
• combine the plurality of microphone signals according to a first combination to produce a primary signal having enhanced response in the direction of the user's mouth,
• combine the plurality of microphone signals according to a second combination to produce a reference signal having reduced response in the direction of the user's mouth,
• combine the primary signal and the reference signal in a manner to enhance a voice portion present in both of the primary signal and the reference signal to produce a voice-enhanced signal,
• combine the primary signal and the reference signal in a manner to reduce a voice portion present in both of the primary signal and the reference signal to produce a voice-reduced signal,
• compare the voice-enhanced signal to the voice-reduced signal, and
• provide an output voice signal based upon the comparison.

A non-transitory computer readable medium having instructions encoded thereon that, when executed by a processor, cause the processor to perform a method comprising:

• receiving a plurality of microphone signals;
• combining the plurality of microphone signals according to a first combination to produce a primary signal having enhanced response in the direction of the user's mouth;
• combining the plurality of microphone signals according to a second combination to produce a reference signal having reduced response in the direction of the user's mouth;
• combining the primary signal and the reference signal in a manner to enhance a voice portion present in both of the primary signal and the reference signal to produce a voice-enhanced signal;
• combining the primary signal and the reference signal in a manner to reduce a voice portion present in both of the primary signal and the reference signal to produce a voice-reduced signal;
• comparing the voice-enhanced signal to the voice-reduced signal;
• and
• providing an output voice signal based upon the comparison.