Abstract: A self-calibration system may include a housing including a first calibration circuit configured to coordinate with a second calibration circuit to execute a calibration sequence for an active noise cancelling (ANC) earphone. The housing further includes a cavity configured to accommodate the ANC earphone, wherein the cavity is contoured to simulate the ANC earphone in a user's ear. The housing further includes a calibration microphone coupled with the first calibration circuit and configured to measure calibration sound waves from the ANC earphone, and a calibration speaker configured to emit calibration sound waves to the ANC earphone.

Abstract: A self-calibration system may include a housing including a first calibration circuit configured to coordinate with a second calibration circuit to execute a calibration sequence for an active noise cancelling (ANC) earphone. The housing further includes a cavity configured to accommodate the ANC earphone, wherein the cavity is contoured to simulate the ANC earphone in a user's ear. The housing further includes a calibration microphone coupled with the first calibration circuit and configured to measure calibration sound waves from the ANC earphone, and a calibration speaker configured to emit calibration sound waves to the ANC earphone.

Abstract: Systems and methods for audio listening devices, comprise a speaker coupled to a first housing, a sound port having a first end and a second end, wherein the first end is coupled to the first housing, and the second end is configured to be inserted in an ear canal of a person such that sound waves emitted from the speaker propagates via a secondary path to the ear canal through the sound port, active noise cancellation (ANC) components configured to generate anti-noise signals through the micro-speakers to cancel external noise, and a first microphone disposed within the sound port at the second end of the sound port such that the first microphone is configured to detect the anti-noise signal that propagates through the sound port via the secondary path and the external noise that propagates via a primary path.

Abstract: Speaker performance may be improved by increasing the effective acoustic chamber volume by fluidically connecting a speaker chamber containing a speaker with a mechanical housing. Additionally, the performance of left and right speakers may be balanced. Such balancing may be through equalization of the left and right speakers, balancing the acoustic impedance through sizing the openings between the speaker chambers and mechanical housings, and/or balancing of acoustic volumes within the speakers through use of ballast or acoustic expansion material to increase or decrease the effective acoustic volume of one of the speakers.

Abstract: Speaker performance may be improved by increasing the effective acoustic chamber volume by fluidically connecting a speaker chamber containing a speaker with a mechanical housing. Additionally, the performance of left and right speakers may be balanced. Such balancing may be through equalization of the left and right speakers, balancing the acoustic impedance through sizing the openings between the speaker chambers and mechanical housings, and/or balancing of acoustic volumes within the speakers through use of ballast or acoustic expansion material to increase or decrease the effective acoustic volume of one of the speakers.

Abstract: Systems and methods include a wind detector to receive audio input signals and output a wind detection flag including a single channel wind detection flag and a cross channel wind detection flag, each wind detection flag indicating a presence or absence of wind noise, and a fusion smoothing module to receive the plurality of wind detection flags and generate an output wind detection flag. Microphones generate the plurality of audio input signals. The wind detector and the fusion smoothing module may comprise program instructions stored in the memory for execution by a digital signal processor. The wind detector is a single channel detector to receive a single audio channel of the audio input signal and generate the single channel wind noise flag, and a cross-channel detector to compute auto correlations and a cross correlation between two or more audio channels.

Abstract: Active noise cancellation (ANC) systems and methods include a reference sensor to sense external noise and generate a reference signal, an error sensor to sense noise in a noise cancellation zone and generate an error signal, a feedforward ANC subsystem to receive the reference and error signals and generate a first anti-noise signal to cancel external noise in a noise cancellation zone, a feedback ANC subsystem to receive the error signal and generate a second anti-noise signal to cancel the external noise in the cancellation zone, a wind detector to detect whether wind noise is present in the reference signal and output a wind noise detection status, and wind handler to control adaptation processing of the feedforward ANC subsystem and the feedback ANC subsystem in accordance with the wind noise detection status and mixing of the first and second anti-noise signals to generate an output anti-noise signal.

Abstract: A system and a method provide for protecting a loudspeaker from thermal and/or mechanical failure by monitoring for over-temperature and over-power conditions. The system generates a first gain from a first speaker protection controller in response to a driving voltage and/or a driving current of a loudspeaker, and generates a second gain from a second speaker protection controller in response to the driving voltage and/or a driving current of the loudspeaker, if the temperature exceeds a thermal limit or if the power exceeds a maximum power. The system applies the second gain to an audio signal to lower the audio signal if the first speaker protection controller fails.

Abstract: Adaptive noise cancellation systems and methods comprise a reference sensor operable to sense environmental noise and generate a corresponding reference signal, an error sensor operable to sense noise in a noise cancellation zone and generate a corresponding error signal, a noise cancellation filter operable to receive the reference signal and generate an anti-noise signal to cancel the environmental noise in the cancellation zone, an adaptation module operable to receive the reference signal and the error signal and adaptively adjust the anti-noise signal, and a transient activity detection module operable to receive the reference signal, detect a transient noise event and selectively disable the adaptation module during the detected transient noise event.

Abstract: Adaptive noise cancellation systems and methods include a reference sensor to sense environmental noise and generate a corresponding reference signal, an error sensor to sense noise in a noise cancellation zone and generate a corresponding error signal, a noise cancellation path including a noise cancellation filter and a variable gain component, the noise cancellation path receiving the reference signal and generating an anti-noise signal to cancel noise at an eardrum reference point, and an adaptation module to receive the reference signal and the error signal and adaptively adjust weights of the noise cancellation filter and/or the variable gain component. An adaptive gain control block updates the variable gain component. Inputs to the adaptive gain control block are conditioned using programmable filters to protect against low frequency transients and/or high frequency distractors in the environmental noise. The programmable filters are tuned to optimize cancellation at an eardrum reference point.

Abstract: Adaptive noise cancellation systems and methods comprise a reference sensor operable to sense environmental noise and generate a corresponding reference signal, an error sensor operable to sense noise in a noise cancellation zone and generate a corresponding error signal, a noise cancellation filter operable to receive the reference signal and generate an anti-noise signal to cancel the environmental noise in the cancellation zone, an adaptation module operable to receive the reference signal and the error signal and adaptively adjust the anti-noise signal. The adaptation module includes a noise amplification control module operable to adaptively control noise amplification in at least one hiss region of the anti-noise signal, while achieving cancellation in non-hiss regions of the anti-noise signal.

Abstract: A system and a method provide for protecting a loudspeaker from thermal and/or mechanical failure by monitoring for over-temperature and over-power conditions. The system generates a first gain from a first speaker protection controller in response to a driving voltage and/or a driving current of a loudspeaker, and generates a second gain from a second speaker protection controller in response to the driving voltage and/or a driving current of the loudspeaker, if the temperature exceeds a thermal limit or if the power exceeds a maximum power. The system applies the second gain to an audio signal to lower the audio signal if the first speaker protection controller fails.

Abstract: An active noise cancellation system includes a sensor operable to sense environmental noise and generate a corresponding reference signal, a fixed noise cancellation filter including a predetermined model of the active noise cancellation system operable to generate an anti-noise signal, and a tunable noise cancellation filter operable to modify the anti-noise signal in accordance with stored coefficients, wherein the tunable noise cancellation filter is further operable to modify the stored coefficients in real-time based on user feedback and generate a tuned anti-noise signal that models tunable deviations from the predetermined noise model. A graphical user interface is operable to receive user adjustments of tunable parameters in real-time, the tunable parameters corresponding to at least one of the stored coefficients.

Abstract: A system for controlling distortion comprising a total harmonic distortion (THD) modeling system configured to apply a chirp signal to a system and to identify one or more frequency bands at which distortion is present, and to apply a ramping signal to identify for each of the one or more frequency bands an input signal level at which distortion is initiated. A signal processing system configured to receive an input signal, to determine whether frequency components are present in the input signal that are associated with the one or more frequency bands at which distortion is present, and to limit the amplitude of the input signal at the one or more frequency bands, such as by applying dynamic range compensation.

Abstract: A system for detecting motion comprising a first speaker, a first microphone separated from the first speaker by a distance D1, a sound generator, an echo parameter measurement device and an echo parameter monitor, wherein the echo parameter monitor stores two or more sequential echo parameters and generates a motion indicator if the two or more sequential echo parameters indicate a change in an acoustic echo path that exceeds a predetermined threshold.

Abstract: A method for continuously estimating reverberation decay comprising receiving a sequence of audio data samples. Determining whether a plateau is present in the sequence of audio data samples. Generating one or more reverberation parameters from the sequence of audio data samples if it is determined that the plateau is present.

Abstract: A system and apparatus for constructing a displacement model across a frequency range for a loudspeaker is disclosed. The resultant displacement model is centered around the distortion point. Once a distortion model is constructed it can be incorporated into an audio driver to prevent distortion by incorporating the model and a distortion compensation unit with a conventional audio driver. Various topologies can be used to incorporate a distortion model and distortion compensation unit into an audio driver. Furthermore, a wide variety of distortion compensation techniques can be employed to avoid distortion in such an audio driver.

Abstract: Peak reduction and power limitations are used to prevent distortion and protect components. In a cellular telephone, peak reduction can be based on battery power level to prevent electrical distortion from saturation. In addition peak reduction can be used to prevent mechanical distortion such as rub and buzz. Dynamic range compression can be used for peak reduction. In another application dynamic range compression can be used to control the power output to protect a speaker from damage. One example of a dynamic range compressor/peak limiter comprises a look-ahead buffer and an analysis engine. For example, the look-ahead buffer holds a window of samples of a signal. The analysis engine selects a gain envelope function on the basis of the samples, for example, by selecting the Pth sample in the buffer whenever that sample exceeds a given threshold.

Abstract: A method for continuously estimating reverberation decay comprising receiving a sequence of audio data samples. Determining whether a plateau is present in the sequence of audio data samples. Generating one or more reverberation parameters from the sequence of audio data samples if it is determined that the plateau is present.

Abstract: A system for detecting motion comprising a first speaker, a first microphone separated from the first speaker by a distance D1, a sound generator, an echo parameter measurement device and an echo parameter monitor, wherein the echo parameter monitor stores two or more sequential echo parameters and generates a motion indicator if the two or more sequential echo parameters indicate a change in an acoustic echo path that exceeds a predetermined threshold.