Adaptive filters output a cancellation sound from a speaker, a selector selects outputs of a plurality of auxiliary filters each corresponding to different positions, a subtractor subtracts the selected output from the output of the microphone and outputs the subtracted output to the adaptive filter as an error signal, and a position detection device detects a position of a head of a user. A transfer function estimated so that the error signal becomes 0 when noise is canceled at the corresponding position is preset in the auxiliary filter. When the auxiliary filter corresponding to the position close to the head of the user changes, the switching control unit stepwise increases the frequency with which the output of the auxiliary filter is selected by the selector to 100%.

A sound absorbing device according to an exemplary embodiment of the present invention comprises a plurality of sound absorbing cells arranged adjacent to each other on a plane, and each of the plurality of sound absorbing cells includes: a chamber having a volume therein, and in which a plurality of micro holes is perforated on a front surface in which a sound wave is incident; and a neck part introduced and extended to a rear of the front surface and penetrated by a through hole for communicating the outside and the chamber.

The present disclosure provides an active noise control audio device, method and storage medium. The device includes: a speaker, a microphone, an analog filter, and a processing circuit. The speaker used to generate a noise reduction sound; the microphone used to collect an environmental noise and the noise reduction sound and generate a first analog signal; the analog filter used to provide a gain for the first analog signal and to generate a second analog signal, the second analog signal driving the speaker to generate the noise reduction sound; and the processing circuit used to send a control instruction to the analog filter to adjust the gain and a phase shift of the analog filter according to the first analog signal and the second analog signal.

Various implementations include a method for implementing a computational architecture for a personal active noise reduction (ANR) device. A method includes receiving a source audio stream with a first DSP and performing ANR on the source audio stream utilizing operational parameters stored in the first DSP; outputting a processed audio stream from the first DSP; generating state data with a second DSP in response to an analysis of at least one of the source audio stream, microphone inputs and the processed audio stream, and communicating signals to the first DSP over a common bus coupled to the first and second DSPs to alter the operational parameters in the first DSP; and utilizing a general purpose processor coupled to both the first DSP and the second DSP to communicate control signals with a communication interface, process state data from the second DSP, and alter the operational parameters in the first DSP.

A helmet including an active noise cancellation (ANC) system which includes a first reference microphone for measuring sound pressure at a first location on a first side of the helmet, the first location between a defined spatial region and a first source of sound and a second reference microphone for measuring sound pressure at a second location, different to the first location, on the first side. The second location is between the defined spatial region and a second source of sound. A loud speaker is provided in or adjacent to the defined spatial region. A control unit determines, based on output signals from the first and second microphones, a drive signal for driving the loudspeaker to generate a sound signal that at least partially attenuates, in the defined spatial region and in the first frequency range, the sound signals from the first and second noise sources.

The improved active noise cancellation system for forced air heating or cooling systems onboard aircraft employs a duct having a proximal end coupled to the fan unit to entrain the airflow stream in the direction of a distal end of the duct. A reference sensor is positioned within the proximal end of the duct. A means is provided for injecting an audio frequency control signal into the airflow stream in a manner that does not substantially impede the airflow stream. An error sensor is positioned at the distal end of the duct where it is responsive to sounds carried by the airflow stream, including the audio frequency control signal. An electronic circuit coupled to the reference sensor and to the error sensor supplies a noise abating control signal to energize the control transducer and thereby substantially reduce at least one noise harmonic of the fan unit through destructive interference.

Disclosed herein are a speaker device having a built-in microphone and a noise cancellation method using the same. The speaker device having the built-in microphone includes a microphone module picking up sound from a medium to generate a sound pickup signal, a speaker driver transmitting vibration corresponding to a reverse-phase signal of the sound pickup signal to tire medium, and a controller receiving the sound pickup signal from the microphone module, generating the reverse-phase signal of the sound pickup signal, and transmitting the reverse-phase signal to the speaker driver.

The present disclosure relates to the technical field of earphone and provides to an active noise reduction earphone. The active noise reduction earphone includes an earphone shell, a speaker, a sound outlet mouth, a first feedback digital microphone, a second feedback digital microphone and a sound collecting channel. Herein, the speaker divides the earphone shell into the front speaker cavity and the back speaker cavity; the sound outlet mouth is arranged to be faced to the speaker to output the sound emitted by the speaker; the first feedback digital microphone is arranged at the first noise reduction sound collecting hole preset in the back speaker cavity to collect external ambient noise; the sound in the ear canal is collected through the sound collecting channel, and the second feedback digital microphone isolates the sound collecting channel from the front speaker cavity.

The improved active noise cancellation system for forced air heating or cooling systems onboard aircraft employs a duct having a proximal end coupled to the fan unit to entrain the airflow stream in the direction of a distal end of the duct. A reference sensor is positioned within the proximal end of the duct. A means is provided for injecting an audio frequency control signal into the airflow stream in a manner that does not substantially impede the airflow stream. An error sensor is positioned at the distal end of the duct where it is responsive to sounds carried by the airflow stream, including the audio frequency control signal. An electronic circuit coupled to the reference sensor and to the error sensor supplies a noise abating control signal to energize the control transducer and thereby substantially reduce at least one noise harmonic of the fan unit through destructive interference.

Various implementations include a method for implementing a computational architecture for a personal active noise reduction (ANR) device. A method includes receiving a source audio stream with a first DSP and performing ANR on the source audio stream utilizing operational parameters stored in the first DSP; outputting a processed audio stream from the first DSP; generating state data with a second DSP in response to an analysis of at least one of the source audio stream, microphone inputs and the processed audio stream, and communicating signals to the first DSP over a common bus coupled to the first and second DSPs to alter the operational parameters in the first DSP; and utilizing a general purpose processor coupled to both the first DSP and the second DSP to communicate control signals with a communication interface, process state data from the second DSP, and alter the operational parameters in the first DSP.