In one aspect a method that includes receiving an input signal captured by one or more first sensors associated with an active noise reduction (ANR) device, and processing the input signal using a first filter disposed in an ANR signal path to generate a first signal for an acoustic transducer of the ANR device. The input signal is processed in a pass-through signal path disposed in parallel with the ANR signal path to generate a second signal for the acoustic transducer, wherein the pass-through signal path allows a portion of the input signal to pass through to the acoustic transducer in accordance with a variable gain. One or more second sensors detect an existence of a condition likely to cause instability in the pass-through signal path, and in response, the variable gain is adjusted. A driver signal for the acoustic transducer is generated using an output based on the adjusted gain.

The disclosure includes a headset comprising one or more earphones including one or more sensing components. The headset also includes one or more voice microphones to record a voice signal for voice transmission. The headset also includes a signal processor coupled to the earphones and the voice microphones. The signal processor is configured to employ the sensing components to determine a wearing position of the headset. The signal processor then selects a signal model for noise cancellation. The signal model is selected from a plurality of signal models based on the determined wearing position. The signal processor also applies the selected signal model to mitigate noise from the voice signal prior to voice transmission.

Engine order cancellation (EOC) systems generate feed forward noise signals based on the engine or other rotating shaft RPM and use those signals and adaptively configured W-filters to reduce the in-cabin SPL by radiating anti-noise through speakers. An EOC system may include a signal analysis controller for detecting non-stationary events, such as speech, based on parameters sampled from a current frame of error signals output from microphones positioned in various locations of a vehicle passenger cabin. Upon detection, the signal analysis controller may mitigate the effects of the non-stationary event to prevent the EOC system from boosting noise or contributing to a speech-like post-echo in the passenger cabin. For example, if speech is detected in a frame, then the adaptation can be frozen for that frame. Alternatively, the signal analysis controller may adaptively subtract voice signals out of the error microphone signal.

Engine order cancellation (EOC) systems generate feed forward noise signals based on the engine or other rotating shaft RPM and use those signals and adaptively configured W-filters to reduce the in-cabin SPL by radiating anti-noise through speakers. An EOC system may include a drive mode detector for detecting different vehicle drive modes based on an analysis of signals indicative of current vehicle operating conditions. Upon detection, the EOC system may adaptively adjust various tuning parameters for the EOC algorithm based on the current vehicle drive mode. The EOC system may also selectively target different sets of engine orders for noise cancellation according to the current vehicle drive mode based on which engine orders are dominant during that drive mode.

Audio devices and methods are provided for detecting instability in an associated feedforward audio processing system. A microphone provides a feedforward signal for processing by a feedforward filter. The processed signal may provide noise reduction and/or sound enhancement associated with the surrounding environment. The processed signal contributes to a driver signal provided to an acoustic transducer, e.g., a driver, to produce acoustic signals for a user. A processor is configured to detect an indication of instability in one or more of the signals, and to adjust a phase response of the feedforward signal path in response to detecting the indication of instability.

In one aspect a method that includes receiving an input signal captured by one or more first sensors associated with an active noise reduction (ANR) device, and processing the input signal using a first filter disposed in an ANR signal path to generate a first signal for an acoustic transducer of the ANR device. The input signal is processed in a pass-through signal path disposed in parallel with the ANR signal path to generate a second signal for the acoustic transducer, wherein the pass-through signal path allows a portion of the input signal to pass through to the acoustic transducer in accordance with a variable gain. One or more second sensors detect an existence of a condition likely to cause instability in the pass-through signal path, and in response, the variable gain is adjusted. A driver signal for the acoustic transducer is generated using an output based on the adjusted gain.

Engine order cancellation (EOC) systems generate feed forward noise signals based on the engine or other rotating shaft RPM and use those signals and adaptively configured W-filters to reduce the in-cabin SPL by radiating anti-noise through speakers. An EOC system may include a signal analysis controller for detecting non-stationary events, such as speech, based on parameters sampled from a current frame of error signals output from microphones positioned in various locations of a vehicle passenger cabin. Upon detection, the signal analysis controller may mitigate the effects of the non-stationary event to prevent the EOC system from boosting noise or contributing to a speech-like post-echo in the passenger cabin. For example, if speech is detected in a frame, then the adaptation can be frozen for that frame. Alternatively, the signal analysis controller may adaptively subtract voice signals out of the error microphone signal.

A noise-cancellation system, including: a plurality of sensors, each sensor outputting a sensor signal; a controller configured to receive each sensor signal, and, for each sensor signal, to: determine a power of the sensor signal at a plurality of frequencies; determine a measure of association between the power of the sensor signal at the plurality of frequencies and frequency; and determine whether the measure of association exceeds a predetermined threshold, wherein the processor is further configured to compute a noise-cancellation signal using the sensor signals, wherein the noise-cancellation signal is computed excluding sensor signals that were determined to exceed the predetermined threshold; and at least one actuator receiving the noise-cancellation signal and producing a noise-cancellation audio signal.

A method for reducing the power of an acoustic primary noise signal (d.sub.m(n)) at one or more control positions in a vehicle passenger compartment using an adaptive filter. The method comprising to compare a mean correlation coefficient (.sub.m(n)) between an electrical error signal (e.sub.m(n) and a modelled secondary anti-noise signal .sub.m(n) with at least one predefined threshold (, ).

A headset system comprises: a headset comprising at least one microphone and at least one speaker and configured to transmit and receive sound; a wire system coupled to the headset and comprising a wire; and a control unit coupled to the wire system and configured to: receive from the wire a combined signal comprising a first signal and a second signal, determine that the first signal is a spurious signal, and detect a failure of the wire system based on the determining.