Patent ID: 9721556
Date: 2017-08-01
CPC Classifications: G10K

Claim:
1. A personal audio device, comprising: a personal audio device housing; a transducer mounted on the housing for reproducing an audio signal including both source audio for playback to a listener and an anti-noise signal for countering the effects of ambient audio sounds in an acoustic output of the transducer; an error microphone mounted on the housing in proximity to the transducer for providing an error microphone signal indicative of the acoustic output of the transducer and the ambient audio sounds at the transducer; and a processing circuit that generates the anti-noise signal by adapting a first adaptive filter to reduce the presence of the ambient audio sounds heard by the listener in conformity with the error microphone signal, wherein the processing circuit detects a frequency-dependent characteristic of the source audio that is predominantly a tone and independent of the ambient audio sounds using frequency selective filtering of the source audio and takes action to prevent improper generation of the anti-noise signal in response to detecting the characteristic of the source audio by halting adaptation of the first adaptive filter in response to detecting that the source audio is predominantly the tone.