Apple Inc.

Other

Thomas M Jensen

Andrew P Bright

Vladan Bajic

Tom-Davy W Saux

Hanchi Chen

Brian D Clark

David T Yeh

Christopher R Wilk

Scott P Porter

Ruchir M Dave

Nikolas T Vitt

Alexander V Salvatti

Roderick Brian Hogan

Vasu Iyengar

Yang Lu

Guy C Nicholson

Dana C Massie

Tyrone T Chen

Jeffrey Nathan Gleason

Joyce Gorny

Hannes Breitschaedel

Navneet Gandhi

Max Otto Rasmussen

Victoria Chiu

Ariel A Massias

Ethan R Duni

Aspects of the subject technology relate to electronic devices having speakers. An electronic device may include speaker control circuitry for a speaker. The speaker control circuitry may include multiple parallel prediction blocks that share a single look-ahead delay, and that feed, in parallel, a single controller. The single controller can generate a joint modification to an audio signal based on the parallel outputs of the prediction blocks. The joint modification can then be applied to the audio signal to generate a speaker-protection audio signal that can be output by the speaker. The speaker control circuitry may also include a system modeler that models the speaker system of the electronic device based on feedback measured physical characteristics. In this way, a reduced control safety margin can be achieved by more accurate model predictors, which can allow the controller to safely drive the speaker system to its full capability.

Speaker control

An audio system has an ambient sound enhancement (ASE) function, in which an against-the-ear audio device having a speaker converts a digitally processed version of an input audio signal into amplified sound. The amplification may be in accordance with a stored hearing profile of the user. The audio system also has an acoustic noise cancellation (ANC) function that may be combined in various ways with the ASE function, and that may be responsive to voice activity detection. Other aspects are also described and claimed.

Headphone acoustic noise cancellation and speaker protection

A method for detecting wind using a microphone and a speaker of an electronic device. The method obtains a microphone signal produced by the microphone. The method obtains a speaker input signal produced by the speaker that is emulating a microphone capturing ambient sound in an environment through the speaker. The method determines a coherence between the microphone signal and the speaker input signal and determines whether the coherence is below a coherence intensity threshold. In response to determining that the coherence is below the coherence intensity threshold, the method determines a presence of wind in the environment.

Speaker emulation of a microphone for wind detection

A method performed by an audio system that includes a headset with a left headset housing and a right headset housing. The method includes driving a speaker of the left headset housing with an audio signal, determining whether audio howl is present within the left headset housing by comparing spectral content from a first error microphone signal produced by a first error microphone of the left headset housing and spectral content from a second error microphone signal produced by a second error microphone of the right headset housing, and, in response to determining that audio howl is present, filtering the audio signal to mitigate the audio howl.

Method and system for detecting and mitigating audio howl in headsets

A method for audio signal processing of microphone signals of a headphone. An audio signal from a first microphone of a headphone is filtered by an ANC system to produce a first filtered signal. Dynamic range control is performed upon the first filtered signal to produce a first dynamic range adjusted signal that drives a speaker of the headphone. Other aspects are also described and claimed.

Headphone acoustic noise cancellation and speaker protection or dynamic user experience processing

A method for mitigating noise caused by a loudspeaker in an audio device. The method obtains an audio signal for driving the loudspeaker. The method obtains a system model of the audio device that represents a modeled physical characteristic of the audio device, and determines whether a noise level of loudspeaker induced acoustic noise is greater than a desired sound level by analyzing the audio signal according to the system model, where the noise level and the desired sound level are characterized at the listener's position in an acoustic environment. The method, in response to determining that the noise level is greater than the sound level, processes the audio signal to cause a reduction of the noise level.

Loudspeaker-induced noise mitigation

Method of throttling a pilot tone for thermal monitoring of an electro-mechanical actuator starts by computing a power estimate based on a driving signal. A first temperature estimate is then computed based on the power estimate. The pilot tone may be generated by adjusting a level of the pilot tone based on at least one of the power estimate or the first temperature estimate. The pilot tone is injected into the driving signal to generate a driving output signal that is outputted by an electro-mechanical actuator. Other embodiments are also described.

Method and system of throttling a pilot tone for thermal monitoring of an electro-mechanical actuator

Method to perform thermal monitoring of an electro-mechanical actuator included in a device starts by receiving an in-field calibration temperature from a temperature sensor included in the device. The device may also receive an in-field calibration resistance from a resistance calculator included in the device. A calculated thermal coefficient of resistivity of the electro-mechanical actuator is then computed using an equation that relates the calculated thermal coefficient of resistivity to the in-field calibration temperature. The calculated thermal coefficient of resistivity changes based on the in-field calibration temperature. The equation includes parameters that are stored in the device. A temperature estimate of the electro-mechanical actuator is them computed based on the calculated thermal coefficient of resistivity. Other embodiments are also described.

Electronic devices and method for thermal monitoring of an electro-mechanical actuator

A micro speaker having a capacitive sensor to sense a motion of a speaker diaphragm, is disclosed. More particularly, embodiments of the micro speaker include a conductive surface of a diaphragm facing conductive surfaces of several capacitive plate sections across a gap. The diaphragm may be configured to emit sound forward away from a magnet of the micro speaker, and the capacitive plate sections may be supported on the magnet behind the diaphragm. In an embodiment, the gap provides an available travel for the diaphragm, which may be only a few millimeters. A sensing circuit may sense capacitances of the conductive surfaces to limit displacement of the diaphragm to within the available travel.

Capacitive position sensing for transducers

In one aspect, multiple adaptive W filters and associated adaptive filter controllers are provided that use multiple reference microphone signals to produce multiple, 'component' anti-noise signals. These are gain weighted and summed to produce a single anti-noise signal, which drives an earpiece speaker. The weighting changes based on computed measures of the coherence between content in each reference signal and content in an error signal. Other embodiments are also described and claimed.

Active noise cancellation using multiple reference microphone signals

An active noise control (ANC) processor has an adaptive filter that uses a reference signal to produce an anti-noise signal, and an error signal to evaluate cancellation performance. An adaptive filter algorithm engine configures the filter coefficients of the adaptive filter, in accordance with pre-shaped versions of the error and reference signals. The pre-shaping filter has a high-pass transfer function and enables the adaptive algorithm engine to increase noise cancellation performance in a high frequency band during the presence of focused or narrow-band noise energy in a low frequency band. Other embodiments are also described and claimed.

Prevention of ANC instability in the presence of low frequency noise

A feed forward active noise cancellation (ANC) system for use in a portable audio device has an adaptive digital filter and a reference microphone. A non-adaptive pre-shaping digital filter has an input coupled to the reference microphone and is in series with, and in front of, the adaptive filter. The pre-shaping filter is minimum phase and presents at least 2 dB more gain over a low audio frequency band than over a high audio frequency band. This may help compensate for low frequency band difficulties, and may thereby extend ANC bandwidth at the low end without a worsening impact on the high end. Other embodiments are also described and claimed.

Pre-shaping series filter for active noise cancellation adaptive filter

A passenger headrest is platform deployable and stowable from a passenger seat. The platform operates as a rear headrest and is pivoted to a forward position to serve as a forward leaning face-headrest. The headrest includes a headrest platform that is attached to an adjustable post made of tubular construction and having a plurality of holes. The adjustable post is concentrically dimensioned to be slidably received by a tubular bar. The tubular bar has a set of holes and is pivotably attached to the passenger seat. A first connector secures the adjustable post and tubular bar to each other. The headrest is pivotable through a range of motion adjusted by a passenger, wherein the passenger selects an inclination angle. The inclination angle used by the passenger is established via a second connector that secures the tubular bar to the seat.

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San Francisco, CA, United States of America

Thomas M Jensen