At least one embodiment is directed to a method for automatically activating ambient sound pass-through in an earphone in response to a detected keyword in the ambient sound field of the earphone user, the steps of the method comprising at least receiving at least one ambient sound microphone (ASM) signal; receiving at least one audio content (AC) signal; and comparing the ASM signal to a keyword and if the ASM signal matches a keyword then an AC gain is created.

An active noise control device reduces noise inside a cabin of a car. The active noise control device includes: a controller that decreases a signal level of a canceling signal when a signal level of a received reference signal is lower than a threshold; and a threshold controller that changes the threshold based on at least one of a signal level of an error signal and information on the car.

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 spot noise generator includes a mask component, a polyphase synthesizer, a first signal channel and second signal channel. The mask component has a narrowband noise input, a desired frequency channels word input, a first channel output and a second channel output. The narrowband noise input signal is a digital narrowband noise signal sampled approximately at the Nyquist rate. The desired frequency channels word selects one of the group consisting of the first channel output, the second channel output and a combination of the first channel output and the second channel output. The polyphase synthesizer synthesizes the first channel output signal, synthesizes the second channel output signal and outputs a desired noise signal based on the synthesized first channel output signal and the synthesized second channel output signal.

A spot noise generator includes a mask component, a polyphase synthesizer, a first signal channel and second signal channel. The mask component has a narrowband noise input, a desired frequency channels word input, a first channel output and a second channel output. The narrowband noise input signal is a digital narrowband noise signal sampled approximately at the Nyquist rate. The desired frequency channels word selects one of the group consisting of the first channel output, the second channel output and a combination of the first channel output and the second channel output. The polyphase synthesizer synthesizes the first channel output signal, synthesizes the second channel output signal and outputs a desired noise signal based on the synthesized first channel output signal and the synthesized second channel output signal.

An active noise cancellation system and method, in which an active noise controller generates an anti-noise signal based on an error signal, and a loudspeaker operatively coupled to the active noise controller converts the anti-noise signal into anti-noise sound. An acoustic error sensor operatively coupled to the active noise controller picks up sound and converts the picked-up sound into the error signal. The acoustic error sensor is disposed at a front face of the loudspeaker.

An audio processing system for a listening device includes an input device, a voice activity detector and a ratio-based attenuator. The input device is configured to receive a first audio signal emanating from an environment and including a signal of interest. The voice activity detector is configured to generate a control signal in response to the first audio signal. The ratio-based attenuator is configured to receive the control signal and determine whether the signal level of the first audio signal exceeds the signal level of an audio signal received from an audio playback device by at least a target difference. If so, then the audio level of the playback audio signal is maintained. Otherwise, the audio level of the playback audio signal is adjusted, where, at the adjusted value, the first signal level exceeds the playback signal level by at least the target difference.

An acoustic noise reduction (ANR) headphone described herein has current detection circuitry that detects current consumed by an acoustic driver amplifier as a result of pressure changes due to a tapping of the headphone. Tapping may be performed to change an audio feature or operating mode of the audio system for the headphone. The current detection circuitry senses a characteristic of the current consumed by the acoustic driver amplifier that can be used to determine an occurrence of a tap event. Examples of a characteristic include an amplitude, waveform or duration of the sensed current. Advantageously, the ANR headphones avoid the need for control buttons to initiate the desired changes to the audio feature or operating mode.

A method for processing signals, a terminal device, and a non-transitory computer-readable storage medium are provided. The method includes the following. When a user talks through the headphone, a first sound signal of external environment and a second sound signal of a talking party are alternately recorded with a headphone. A third sound signal of external environment is obtained, by eliminating voices in the first sound signal according to the second sound signal. Feature audio in the third sound signal of external environment is identified and reminding information corresponding to the feature audio is acquired. Inquire of the user whether the third sound signal is critical according to the reminding information, when the talk ends. An input operation of the user is detected and the third sound signal is processed according to the input operation of the user.

Embodiments can provide individualized controlling of noise injection during startup of a crystal oscillator. In some embodiments, a simple learning block can be placed in parallel to a oscillator circuit to control noise injection during the startup of the crystal oscillator. The learning block can be configured to control the noise injection during the startup of the crystal oscillator by determining whether the crystal oscillator has been stabilized. In some embodiments, an adjustment block may be employed to adjust the count determined by the learning block based on one or more measured characteristics of the crystal oscillator during a startup of the crystal oscillator. In some embodiments, a simple block that creates a negative capacitance can be configured in parallel to the crystal oscillator.