A noise reducing device includes: an acoustic-to-electric conversion section for collecting noise and outputting an analog noise signal; an analog-to-digital conversion section for converting the analog noise signal into a digital noise signal; and a digital processing section for generating a digital noise reducing signal on a basis of the digital noise signal and a desired parameter. The device further includes: a retaining section for retaining a plurality of parameters corresponding to a plurality of kinds of noise characteristics; a setting section for setting one of the plurality of parameters as the desired parameter of the digital processing section; a digital-to-analog conversion section for converting the digital noise reducing signal into an analog noise reducing signal; and an electric-to-acoustic conversion section for outputting noise reducing sound on a basis of the analog noise reducing signal.

An audio customization system responsive to one or more inputs that enhance aspects of an audio output and one or more inputs that diminish aspects of an audio output. The system is set up to be able to lessen the influence of ambient audio or in some situations enhance ambient audio over source audio. The system may specify aspects of audio to be modified by specification of filtering algorithm, characterization of audio samples, monitored distortion, user selection, location specification or environmental specification.

A signal processing device includes a coefficient updater configured to calculate a filter coefficient based on a reference signal, an error signal, and an update parameter to set the filter coefficient in a noise cancelling filter. A parameter adjuster adjusts the update parameter according to fluctuation of the reference signal produced from an output of a reference microphone.

An apparatus on a vehicle comprises one or more sensors, one or more nozzles that output fluid to clean the respective one or more sensors, and a compressor that generates fluid such as compressed air. The compressor is in fluid communication with the one or more nozzles. The apparatus further comprises one or more processors, and a memory storing instructions that, when executed by the one or more processors, cause the system to determine information of an acoustic emission from the compressor and to counteract the acoustic emission based on the determined information.

A vehicle includes an engine and/or powertrain producing noise that is audible in a passenger compartment of the vehicle when the engine and/or powertrain is running. An active noise control arrangement includes a first loudspeaker disposed within a passenger compartment of the vehicle. A digital signal processor receives audio data and transmits an audio signal to the first loudspeaker dependent upon the audio data. A microphone is disposed within the passenger compartment and converts the sound from the first loudspeaker and the noise within the passenger compartment into a microphone signal. The microphone signal is transmitted to the digital signal processor, and the digital signal processor modifies the audio signal such that the audio signal attenuates the noise in the passenger compartment. A vehicle processor transmits a simulated noise signal to a second loudspeaker for use in testing effectiveness of the active noise control arrangement in attenuating noise when the engine and/or powertrain is not running and not producing noise.

A sound processing apparatus includes a first microphone which acquires environmental sound, a second microphone which acquires sound of a noise source, and a CPU which causes the sound processing apparatus to function as a noise detection unit configured to generate a noise signal of the noise source according to a sound signal from the second microphone, the noise detection unit reducing sound other than noise of the noise source from the sound signal from the second microphone and generating the noise signal, and a noise reducing unit configured to reduce the noise of the noise included in a sound signal from the first microphone using the sound signal from the noise detection unit.

A method for operating a hearing device for being worn at least partially within an ear canal of a user, including an ear canal microphone, a filtering unit and an electrical-to-acoustical converter, capable of active occlusion control (AOC) and allowing the user to adjust the AOC functionality according to his or her preferences. The method includes picking up an ear canal internal sound at the microphone which provides a signal representative of the internal sound, filtering the signal with the filtering unit to reduce a perceived level of body sounds produced by the user, providing the filtered signal to the converter which outputs sound into the ear canal, and changing at least one setting or parameter of the filtering unit in dependence of a control signal, wherein the control signal is initiated by the user. Moreover, a hearing device adapted to perform the method is provided.

A personal audio device, such as a wireless telephone, includes an adaptive noise canceling (ANC) circuit that adaptively generates an anti-noise signal from a reference microphone signal and injects the anti-noise signal into the speaker or other transducer output to cause cancellation of ambient audio sounds. An error microphone is also provided proximate to the speaker to provide an error signal indicative of the effectiveness of the noise cancellation. A secondary path estimating adaptive filter is used to estimate the electro-acoustical path from the noise canceling circuit through the transducer so that source audio can be removed from the error signal. A level of the source audio with respect to the ambient audio is determined to determine whether the system may generate erroneous anti-noise and/or become unstable.

A first control signal filter to which a cosine wave oscillating at a control frequency is input; a second control signal filter to which a sine wave oscillating at the control frequency is input; a control signal adder for outputting a control signal generated by adding an output of the first control signal filter and an output of the second control signal filter; a filter coefficient update unit for updating filter coefficients of the first control signal filter and the second control signal filter; and a frequency correction value calculation unit for calculating a frequency correction value for correcting the control frequency on the basis of the control signal and the control frequency.

A personal audio device, such as a wireless telephone, includes an adaptive noise canceling (ANC) circuit that adaptively generates an anti-noise signal from an output of a microphone that measures ambient audio. The anti-noise signal is combined with source audio to provide an output for a speaker. The anti-noise signal causes cancellation of ambient audio sounds that appear at the microphone. A processing circuit estimates a level of background noise from the microphone output and sets a power conservation mode of the personal audio device in response to detecting that the background noise level is lower than a predetermined threshold.