System for howling prevention in ear-wearable device

A method of howling prevention in an ear-wearable device, comprising:

• receiving an error signal from an inward facing microphone of the ear-wearable device;
• via an active noise controller W_b, providing a noise control signal based on the error signal;
• via a processing block, providing an amplified hearing signal based on a reference audio signal from a source device;
• combining the noise control signal and the amplified hearing signal to form a drive signal used to drive a receiver that outputs an acoustic signal in response thereto;
• determining a transform function K that represents an approximation of an inverse of the active noise controller W_b;
• applying the transform function K to the drive signal to determine an inverse filter signal;
• applying a filter Q to the error signal to produce a filtered error signal, the filter Q compensating for deficiencies in the transform function K;
• and
• disabling the active noise controller W_b when an anomalous similarity is detected between the filtered error signal and the inverse filter signal.

The method of claim 22, further comprising preventing the disabling of the active noise controller W_b when an anomalous similarity is detected based on one or more of:

• detecting the own voice of a wearer of the ear-wearable device in a microphone signal;
• detecting movement of the ear-wearable device;
• detecting a user is walking, jumping, and/or headshaking;
• detecting a user is in a low frequency noise environment;
• and
• an environmental classification.

A computer-readable medium that stores instructions configured to cause a computing device to:

• receive an error signal from an inward facing microphone of an ear-wearable device;
• via an active noise controller W_b, provide a noise control signal based on the error signal;
• via a processing block, provide an amplified hearing signal based on a reference audio signal from a source device;
• combine the noise control signal and the amplified hearing signal to form a drive signal used to drive a receiver that outputs an acoustic signal in response thereto;
• determine a transform function K that represents an approximation of an inverse of the active noise controller W_b;
• apply the transform function K to the drive signal to determine an inverse filter signal;
• apply a filter Q to the error signal to produce a filtered error signal, the filter Q compensating for deficiencies in the transform function K;
• and
• disable the active noise controller W_b when an anomalous similarity is detected between the filtered error signal and the inverse filter signal.