Feedback acoustic noise cancellation tuning

An in-ear headphone comprising:

• a speaker;
• an internal microphone;
• an enclosure that comprises the speaker and the internal microphone;
• an opening that extends through the enclosure to directly connect an inside portion of the in-ear headphone to an ambient environment outside the enclosure;
• a processor;
• and
• memory having instructions which when executed by the processor causes the in-ear headphone to
• receive a microphone signal from the internal microphone that indicates a current sound pressure level (SPL);
• determine an active noise cancellation (ANC) filter based on the microphone signal;
• and
• generate an anti-noise signal using the ANC filter;
• and
• driving the speaker using the anti-noise signal to reduce the SPL in an ear canal of the user as much as 25 dB at a frequency within a frequency range.

An article of manufacture comprising a non-transitory machine-readable medium having instructions stored therein that when executed by a processor of an in-ear headphone cause the headphone to

• receive, from an internal microphone of the in-ear headphone, a microphone signal that indicates a current sound pressure level (SPL) in an ear canal of a user, wherein the in-ear headphone comprises an opening that extends through an enclosure of the in-ear headphone such that an inside portion of the enclosure directly connects to an ambient environment that is outside the enclosure, thereby reducing a SPL in the ear canal;
• determine an active noise cancellation (ANC) filter based on the microphone signal;
• and
• generate an anti-noise signal using the ANC filter;
• driving a speaker of the in-ear headphone using the anti-noise signal to reduce the current SPL in the ear canal of the user as much as 25 dB at a frequency within a frequency range.