Adaptive howling suppression for active noise control systems

An adaptive howling suppression (AHS) system for integration in an active noise control (ANC) system of a wearable audio component, the AHS system comprising:

• a mode detector;
• a howling detector coupled with the mode detector and configured to couple with an error microphone of the wearable audio component;
• and
• a howling suppressor coupled with the mode detector and the howling detector and configured to couple with an ANC gain block of the ANC system, wherein:
• the howling detector is further configured to first detect, while the howling suppressor is in an idle state, a howling audio signature being output via a speaker of the wearable audio component;
• the howling suppressor is further configured to pre-suppress the howling audio signature by reducing an ANC output gain of the ANC gain block responsive to the first detecting;
• the mode detector is configured to second detect, responsive to the first detecting, whether the wearable audio component is presently in an on-ear condition or in an off-ear condition;
• and
• the howling suppressor is further configured to suppress the howling audio signature by:
• tuning a set of mode-based parameters to on-ear-mode settings responsive to the mode detector second detecting that the wearable audio component is presently in the on-ear condition, or to off-ear-mode settings responsive to the mode detector second detecting that the wearable audio component is presently in the off-ear condition;
• and
• cycling through a set of suppression stages according to the set of mode-based parameters until the howling detector third determines that the ANC output gain is restorable without recurrence of the howling audio signature, the set of suppression stages comprising an ANC gain reduce/detect stage and an ANC gain restore/detect stage.