Reducing an acoustic intensity vector with adaptive noise cancellation with two error microphones

摘要

A second error microphone may be incorporated in a mobile device to allow computation of additional parameters for modifying an adaptive noise cancellation (ANC) algorithm. For example, a first and second acoustic pressure may be calculated from a first and second error microphone of the mobile device. The first and second acoustic pressure may be input to an algorithm for determining an acoustic intensity vector. The ANC algorithm may receive the acoustic intensity vector as an input, and adapt an anti-noise signal to reduce the acoustic intensity vector. Additionally, an input impedance for the error microphones may be calculated from the acoustic pressure to determine coupling between a speaker and a user's ear. The anti-noise algorithm may be adjusted or disabled when the input impedance indicates the user has removed the phone from the user's ear.

主权项

1. A method, comprising:
receiving a first signal from a first microphone, the first microphone facing a user; receiving a second signal from a second microphone, the second microphone facing the user; calculating a parameter proportional to acoustic particle velocity based, at least in part, on the first signal and the second signal; calculating an acoustic intensity vector based, at least in part, on the calculated parameter proportional to the acoustic particle velocity; adjusting an audio output signal for output to a transducer based, at least in part, on the calculated acoustic intensity vector, wherein the step of adjusting the audio output signal comprises adjusting an active noise control algorithm to reduce the acoustic intensity vector; calculating an acoustic impedance based, at least in part, on the calculated parameter proportional to the acoustic particle velocity; and disabling the active noise control algorithm when the determined acoustic impedance indicates the device is removed from the user's ear.