The present invention includes: a housing that includes an arrangement case in which an internal space is formed, and a sound guide tube in which a sound conduction space is formed; a feedback microphone to which an external sound is input; a first speaker unit that outputs a sound; and a second speaker unit that outputs a sound in an output band different from an output band of the sound output from the first speaker unit. The housing has inside a first space and a second space, the feedback microphone and the first speaker unit are arranged in the first space, the second speaker unit is arranged in the second space, and an equalizer that partitions the first space and the second space is disposed between the first speaker unit and the second speaker unit.

Various implementations include a computational architecture for a personal active noise reduction (ANR) device. The device includes a communication interface that receives an audio stream, a driver, a microphone system and an ANR processing platform. The platform includes a first DSP configured to: receive the audio stream and signals from the microphone system, perform ANR on the audio stream according to a set of parameters in the first DSP, and output a processed audio stream. The platform includes a second DSP configured to: generate state data in response to an analysis of the source audio stream, signals from the microphone system, and the processed audio stream; and alter the operational parameters on the first DSP. The platform includes a general purpose processor configured to: communicate control signals with the communication interface, process state data from the second DSP, and alter the parameters on the first DSP.

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.

A method performed by an in-ear headphone that includes a speaker and an internal microphone. The method receives a microphone signal from the internal microphone that indicates a current sound pressure level (SPL) in an ear canal of a user. The current SPL is a result of a control leak from the in-ear headphone into an ambient environment that reduces a SPL in the ear canal between 2 dB and 25 dB at a frequency within a frequency range than if otherwise not present. The method determines an active noise cancellation (ANC) filter based on the microphone signal and generates an anti-noise signal using the ANC filter. The method drives the speaker using the anti-noise signal to reduce the current SPL in the ear canal of the user as much as 25 dB at a frequency within the frequency range.

A unit cell of an artificial phononic crystal for building of an artificial phononic metamaterial, showing reduced mechanical vibrations in a defined frequency range with at least one band gap in the band structure dispersion relation of the unit cell. The unit cell includes at least one building block and at least one mechanical connection connected to the building block, showing reduced mechanical vibrations in a defined frequency range with tailored dispersion properties with at least one band gap is sought. This is accomplished by forming the building block as a toroid, with a central opening and a front surface from which a first multiplicity of struts, which are tiltable relatively to the principal direction, is extending from the front surface. More than one strut is inclined with respect to the principal direction so that a rotation of the toroid around the principal direction is possible.

Various implementations include a computational architecture for a personal active noise reduction (ANR) device. The device includes a communication interface that receives an audio stream, a driver, a microphone system and an ANR processing platform. The platform includes a first DSP configured to: receive the audio stream and signals from the microphone system, perform ANR on the audio stream according to a set of parameters in the first DSP, and output a processed audio stream. The platform includes a second DSP configured to: generate state data in response to an analysis of the source audio stream, signals from the microphone system, and the processed audio stream; and alter the operational parameters on the first DSP. The platform includes a general purpose processor configured to: communicate control signals with the communication interface, process state data from the second DSP, and alter the parameters on the first DSP.

A phononic coupler. In some embodiments, the phononic coupler includes a sheet, including a plurality of standard reflectors, and a plurality of divergent reflectors. The divergent reflectors define, among the standard reflectors, a first waveguide, and a second waveguide. The coupler has a first port, at a first end of the coupler, a second port, at the first end of the coupler, and a third port, at a second end of the coupler. The first waveguide has a first end at the first port. The second waveguide has a first end at the second port, and a second end at the third port. The coupler is configured to couple longitudinal sound waves to both the first port and the second port.

In one aspect, a first device may include at least one processor and storage accessible to the at least one processor. The storage may include instructions executable by the at least one processor to establish a peer to peer network between the first device and a second device. The instructions may also be executable to select the first device to generate noise cancellation signals based on the first device being closer to a source of sound than the second device. The instructions may be further executable to use the first device to generate the noise cancellation signals based on sound from the source of sound, and to transmit the noise cancellation signals over the peer to peer network to the second device.

The present invention provides an audio adjustment method and associated audio adjustment device for active noise cancellation. The audio adjustment method includes: broadcasting a single tone having a frequency f.sub.k; generating M sets of filtering coefficients regarding the frequency f.sub.k, wherein each set of filtering coefficients within the M sets of filtering coefficients includes a combination of an amplitude and a phase, and the M sets of filtering coefficients are different from one another; determining an m.sup.th set of filtering coefficients from the M sets of filtering coefficients to minimize energy corresponding to the frequency f.sub.k; and adjusting the single tone with the m.sup.th set of filtering coefficients to obtain an adjusted single tone corresponding to the frequency f.sub.k.

A first cancellation signal output from a first speaker cancels noise at a first cancellation point, which is a typical position of the right ear of a user, together with a second cancellation signal output from a second speaker. In addition, the second cancellation signal output from the second speaker cancels noise at a second cancellation point, which is a typical position of the left ear of the user, together with the first cancellation signal output from the first speaker. The first speaker and the second speaker are arranged side by side on a second line segment, which passes through the midpoint of a first line segment connecting the first cancellation point and the second cancellation point to each other and is perpendicular to the first line segment, and a range where the relationship between noise and the first cancellation signal and the second cancellation signal is the same as that at the cancellation point is extended.