A noise reduction device includes a processor that converts a noise signal collected by a microphone disposed in a control space into a noise signal in a frequency domain, a storage that stores the converted noise signal in the frequency domain as a reference signal, and a signal generator that generates a noise reduction signal for reducing the noise signal collected by the microphone at a control position of the control space. The processor determines whether or not the noise signal is non-stationary noise based on a frequency characteristic of the converted noise signal in the frequency domain and a frequency characteristic of the reference signal. When it is determined that the noise signal is the non-stationary noise, the processor controls the signal generator so as to cancel generation of the noise reduction signal.

An active noise control device includes a determination unit configured to determine whether an abnormality has occurred in an acceleration sensor based on a direct-current component of a reference signal acquired by the acceleration sensor attached to a vehicle, and a control unit configured to, when the determination unit determines that an abnormality has occurred in any of a plurality of the acceleration sensors, stop generation of the control signal based on the reference signal acquired by the acceleration sensor that has been determined to have the abnormality, and stop updating a filter coefficient of an adaptive filter configured to perform the filtering process on the reference signal acquired by the acceleration sensor that has been determined to have no abnormality.

An integrated circuit for implementing at least a portion of a personal audio device may include a processing circuit to implement an adaptive filter having a response that generates an anti-noise signal to reduce the presence of the ambient audio sounds at an error microphone, implement a coefficient control block that shapes the response of the adaptive filter in conformity with the error microphone signal by computing coefficients that determine the response of the adaptive filter to minimize the ambient audio sounds at the error microphone, and responsive to detecting a condition that triggers a reset of the adaptive filter, increment the coefficients in a plurality of steps from initial values of the coefficients at a time of triggering the reset to final values of the coefficients at a conclusion of the reset.

An electronic device may include at least one microphone, a speaker, and a processor operatively connected to the at least one microphone and the speaker, wherein the processor may be configured to configure an operation frequency of the microphone as a first frequency and receive an external audio signal from the outside of the electronic device through the microphone operating in the first frequency, generate a first audio signal using the received external audio signal, acquire noise signal information, based on the first audio signal, output a second audio signal generated based on the noise signal information through the speaker, determine a second frequency, based on the generated second audio signal, and change the operation frequency of the microphone to the second frequency and receive the external audio signal from the outside of the electronic device through the microphone operating at the second frequency.

An active noise control system selects one reference sensor providing a reference signal with the largest coherence to a noise signal, among a plurality of available reference sensors, as a first entry of a reference sensor set. After selecting the first entry, the active noise control system repeats a process in which a sensor capable of providing the largest information quantity to a current reference sensor set among remaining sensors is selected as a new entry of a reference sensor set, until a desired number of sensors is reached or a desired control level is reached. When the reference sensor set is determined, the active noise control system utilizes the entries of the reference sensor set to generates a noise control signal suitable for canceling the noise signal.

A signal processing device according to an embodiment includes: two or more microphones each provided with a sound collection unit directed to an outside of a housing including a driver unit, a control unit (102b) that performs a hearing control of sound output from the driver unit to a listener based on sound signals collected and output by the two or more microphones, and an adjustment unit (200) that adjusts a degree of the hearing control between a degree for wind and a degree for non-wind based on a correlation between the sound signals.

A method of canceling road noise includes: receiving a first signal from an acceleration sensor disposed at a vehicle and a second signal from a microphone disposed at the vehicle; monitoring, based on the first and second signals, whether an abnormal event has occurred; determining, based on a result from monitoring whether the abnormal event has occurred, a plurality of parameter values for performing adaptive filtering; and performing, based on the determined parameter values, adaptive filtering to generating an output signal for noise canceling.

A system includes a microphone unit coupled to a roof of an autonomous vehicle. The microphone unit includes a microphone board having a first opening. The microphone unit also includes a first microphone positioned over the first opening and coupled to the microphone board. The microphone unit further includes an accelerometer. The system also includes a processor coupled to the microphone unit.

Various implementations include systems for providing enhanced aware mode capabilities in an ANR audio device. In particular implementations, a method includes receiving an ambient noise signal from a microphone associated with a wearable audio device; determining a gain value based on a sound pressure level (SPL) of the ambient noise signal; generating a gain adjusted ambient noise signal by applying the gain value to the ambient noise signal; generating a total external microphone signal by adding the gain adjusted ambient noise signal to a noise reducing ambient signal; generating an expanded audio signal by selectively adjusting a source audio signal based on the gain adjusted ambient noise signal; and combining and outputting the expanded audio signal with the total external microphone signal to an acoustic transducer.

A method of detecting singing of a user of a personal audio device, the method comprising: receiving a first audio signal comprising bone-conducted speech of the user from a first transducer of the personal audio device; monitoring a second audio signal output to a speaker of the personal audio device; and determining whether the user is singing based on the first audio signal and the second audio signal.