Head wearable acoustic system with noise canceling microphone geometry apparatuses and methods

An apparatus to be worn on a user's head, comprising:

• a head wearable device, the head wearable device is configured to be worn on the user's head;
• a first microphone, the first microphone has a first response pattern and the first response pattern has a first major response axis, the first microphone is coupled to the head wearable device, the first microphone is positioned on the head wearable device to receive a voice signal from the user;
• a second microphone, the second microphone is coupled to the head wearable device, the second microphone and the first microphone are separated by a distance on the head wearable device such that a first acoustic distance between the first microphone and the user's mouth is less than a second acoustic distance between the second microphone and the user's mouth when the head wearable device is on the user's head;
• a beamformer, the beamformer is configured to receive input signals from at least the first microphone and the second microphone and to provide a main signal on a main channel and at least one reference signal on at least one reference channel;
• an adaptive noise cancellation unit, the adaptive noise cancellation unit is coupled to receive the main signal and the at least one reference signal from the beamformer, the adaptive noise cancellation unit to reduce a first amount of undesired audio from the main signal to form a filtered output signal;
• a filter control, the filter control is coupled to the beamformer, the filter control to create a control signal from the main signal and the at least one reference signal to control reduction of undesired audio;
• and
• a single channel noise reduction unit, the single channel noise reduction unit is coupled to receive the filtered output signal and is coupled to the filter control, the single channel noise reduction unit reduces a second amount of undesired audio from the filtered output signal to provide mostly desired audio in the main signal.

An apparatus to be worn on a user's head, comprising:

• a head wearable device, the head wearable device having a first microphone and a second microphone;
• a data processing system, the data processing system is configured to process acoustic signals, wherein the acoustic signals are received from the first microphone and the second microphone, and the data processing system is contained within the head wearable device;
• and
• a computer readable medium containing executable computer program instructions, which when executed by the data processing system, cause the data processing system to perform a method comprising:
• receiving a main signal and a reference signal;
• producing a filter control signal from the main signal and the reference signal, the main signal is normalized by the reference signal to provide a normalized main signal to the producing;
• applying a first stage of filtering with the main signal and the reference signal input to a multi-channel filter to reduce a first amount of undesired audio from the main signal, wherein the filter control signal is used to separate desired audio from undesired audio during the applying;
• and
• applying a second stage of filtering to an output of the first stage to create a second reduction in undesired audio from the main signal, the filter control signal is used to separate desired audio from undesired audio in the second stage, the second stage outputs a main signal which is mostly desired audio.

A method, comprising:

• locating a main microphone channel at a first location on a head wearable device, the main microphone channel has a first signal-to-noise ratio when the head wearable device is worn on a user's head and desired audio is received from the user's mouth;
• locating a reference microphone channel at a second location on the head wearable device, the reference microphone channel has a second signal-to-noise ratio when desired audio is received from the user's mouth;
• and
• providing a signal-to-noise ratio difference between the main microphone channel and the reference microphone channel to a noise cancellation system when acoustic signals are received by the main microphone channel and the reference microphone channel, wherein the noise cancellation system is coupled to the head wearable device.