A system including an audio source device having a first microphone and a first speaker for directing sound into an environment in which the audio source device is located and a wireless audio receiver device having a second microphone and a second speaker for directing sound into a user's ear. The audio source device is configured to 1) capture, using the first microphone, speech of the user as a first audio signal, 2) reduce noise in the first audio signal to produce a speech signal, and 3) drive the first speaker with the speech signal. The wireless audio receiver device is configured to 1) capture, using the second microphone, a reproduction of the speech produced by the first speaker as a second audio signal and 2) drive the second speaker with the second audio signal to output the reproduction of the speech.

A fan control system applied to N fans inside a computer system is disclosed, comprising: a main microphone, a control circuitry, a wave generation circuitry and a number N of fan controllers. The control circuitry calculates a basic frequency value according to a temperature inside the computer system, and continuously updates a parameter by any known optimization algorithm according to a main audio signal from the main microphone. The wave generation circuitry generates N square waves according to the basic frequency value and the parameter. The N fan controllers respectively form and transmit N modulation signals to the N fans according to the N square waves and N tachometric signals from the N fans. The parameter is one of a frequency variation and a set of phase differences, and the N square waves have the same frequency.

An urban air mobility (UAM) noise reduction system and method are provided, where the UAM noise reduction system includes a UAM configured to detect and to provide rotation per minute (RPM) information of a propeller and location coordinate information, and a noise canceling device configured to predict a noise canceling sound wave amplitude on the basis of the RPM information of the propeller and the location coordinate information received through the UAM and to output a noise canceling sound wave corresponding to the predicted noise canceling sound wave amplitude to the UAM.

Aspects of the invention are directed towards a system and method for noise suppression. One or more embodiments of the invention describe the method comprising steps of receiving noise by a microphone and deriving a noise signal from the noise, the noise produced by a fan of a fire/smoke detection unit while drawing air and detecting the speed of the fan of the fire/smoke detection unit. The method further describes steps of amplifying the noise signal by the amplifier received from the microphone and producing an anti-phase noise signal by shifting a phase of the amplified noise signal received from the amplifier wherein the anti-phase noise signal is dependent on the detected speed of the fan. The method further describes steps of outputting the anti-phase noise signal through a speaker to suppress the noise produced by the fan of the fire/smoke detection unit while drawing the air.

A system for adjusting volume and ambient sounds in an earphone device with Active Noise Cancelling (ANC) functionality, implemented using a microphone and a signal processor, wherein a signal mixer is configured to, in response to detecting a rotation of a first dial connected to the earphone device, adjust the proportions between a group of signals in a mixed signal generated for the speaker of the earphone device, and thereby enabling precise and intuitive control of both playback volume and ambient sound processing.

A hybrid ANC system that can allow a feedback microphone to receive the same external noise as a feedforward microphone. A processor can generate an anti-noise signal based on what both microphones received to cancel a broader range of frequencies of the external noise.

A projector includes an exterior enclosure having an intake port and a discharge port, a heat source, a fan that causes a cooling gas to flow to the heat source, a loudspeaker that is disposed between one of the two openings, and the fan in the channel of the cooling gas and outputs a sound wave according to a drive signal inputted to the loudspeaker, a characteristic data storage section that stores frequency characteristic data on the frequency characteristics of discrete frequency noise, broadband noise, and in-apparatus environmental noise, and a control section that generates the drive signal, and the control section includes a characteristic acquisition section that acquires the frequency characteristic data corresponding to the rotational speed of the fan per unit time, a waveform generation section that generates the waveform of an interference sound, and a signal output section that outputs the drive signal.

A refrigerator includes a noise reduction device and a machine room that accommodates a condenser and a compressor. The noise reduction device includes a sensing unit configured to measure noise generated from the machine room of the refrigerator and a generating unit configured to output a sound signal having a frequency canceling or reducing the noise. The machine room is defined by a case that has a communication portion configured to communicate a fluid between an inside of the case and an outside of the case to thereby exchange heat between the fluid and the condenser and between the fluid and the compressor.

Provided is a signal processing device that performs noise canceling by combining a feedforward method and a feedback method. A signal processing device includes: a correlation calculation unit that calculates a correlation between a first sound pickup signal by a first microphone installed outside a predetermined region and a second sound pickup signal by a second microphone installed in the predetermined region; a determination unit that determines the correlation; and a control unit that performs control based on a result of the determination. The control unit controls execution of signal processing for generating a cancellation signal to be output within the predetermined region from the first sound pickup signal and the second sound pickup signal or output of the cancellation signal.

Noise abatement within a signal stream containing unwanted signal referred to as noise is performed by acquiring a digitized noise signal and using a digital processor circuit to subdivide the acquired noise signal into different frequency band segments and thereby generate a plurality of segmented noise signals. Then individually for each segmented noise signal, the processor shifts in time the segmented noise signal by an amount dependent on a selected frequency of the segmented noise signal to produce a plurality of shifted segmented noise signals. The precise time shift applied to each noise segment considers the frequency content of the segment and the system processing time. Individually for each segmented noise signal, amplitude scaling is applied. The shifted and amplitude-scaled segmented noise signals are then combined to form a composite anti-noise signal which is output into the signal stream to abate the noise through destructive interference.