A noise-canceling headrest for a vehicle seat, comprising a central part and two side parts, at least one loudspeaker, a microphone, an audio source playback module capable of transmitting an audio signal to the loudspeaker, a noise sensor, and a signal processing circuit configured for: receiving a noise signal and determining a noise correction function, receiving an error signal from the microphone, and updating the noise correction function, generating a noise correction signal by applying the noise correction function to the noise signal, generating a control signal intended for the loudspeaker, by adding together the noise correction signal and the audio signal.

A speaker system includes a cushion body with which a person comes into contact when sitting therein, and a speaker, a front of which is covered by the cushion body. The cushion body includes: a three-dimensional mesh-like elastic part that is formed by a three-dimensionally entangled fiber and bears a load of the person; and a cover member that covers surroundings of the three-dimensional mesh-like elastic part. The cover member includes a first cover member that covers the part of the surroundings of the three-dimensional mesh-like elastic part located at the front of the speaker, and a second cover member that is a remainder of the cover member excluding the first cover member. The first cover member has a higher acoustic transmissivity than the second cover member.

A headrest suitable for being fastened to a vehicle seat having: an upper support portion, a reinforcing frame connected to the upper support portion for fastening the upper support portion to the vehicle seat, and an array of microphones comprising microphones disposed inside seats obtained in the headrest, in such a way that the microphones can be used to capture the sounds from the user sitting on the seat where the headrest is connected, as well as environmental microphones to capture the environmental noise perceived around the headrest.

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.

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 loudspeaker device includes at least one loudspeaker, a loudspeaker holder holding the at least one loudspeaker in a reference range away from the ear of a user by a reference distance, a first microphone collecting an environmental sound and outputting an electrical signal, a second microphone attached to a position where a sound output from the at least one loudspeaker is collected, the second microphone collecting a synthetic sound synthesized from the sound output from the at least one loudspeaker and the environmental sound and outputting an electrical signal, and a processor controlling the at least one loudspeaker so as to output a sound for reducing the environmental sound based on the electrical signals representing the sounds collected by the first microphone and the second microphone.

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.

In a first system signal processing unit, an adaptive filter generates a noise cancel sound, a first system selector selects an output of a first system auxiliary filter corresponding to a noise cancel position matching a detected position of a right ear of a user from a plurality of first system auxiliary filters corresponding to different noise cancel positions, and a first system subtractor subtracts the selected output from an output of a first microphone and outputs the subtracted result as an error signal to a first system adaptive filter and a second system adaptive filter of a second system signal processing unit. The noise cancel positions are arranged at predetermined intervals in a space where the user can move the right ear due to turning and side bending of the head within a predetermined range in the up-down and front-back directions.

A transfer function of a first variable filter is updated to output, from an output of a first seat microphone, a cancel sound that minimizes a level of a signal obtained by subtracting an output of an auxiliary filter that generates a correction signal for correcting a difference between positions of the first seat microphone and the first seat. In the ICC mode in which the uttered voice of the user in the first seat is output from a second seat speaker, a selector sets an uttered voice Dp output from the second seat speaker as an input to the first variable filter, and in the non-ICC mode, the selector sets an output sound of a second seat audio source output from the second seat speaker as an input to the first variable filter. The uttered voice Dp is generated by removing a component of the cancel sound from the output of the first seat microphone.

In a first system signal processing unit, a first system auxiliary filter generates a correction signal for correcting an error signal from a noise signal, a first system subtractor subtracts the correction signal from an output of a first microphone to obtain an error signal, an adaptive filter performs an adaptive operation using the error signal to generate a cancel sound output from a first speaker, and a DMS detects a position of a user's ear. When the position of the user's ear moves, the controller stops the adaptive operation, updates the transfer function of the first system auxiliary filter to the transfer function corresponding to the noise cancel position matching the position of the user's ear, gradually changes the transfer function of the adaptive filter to the transfer function corresponding to the matching noise cancel position, and resumes the adaptive operation after the change is completed.