Abstract: A noise reduction device includes a noise controller, a control sound output component and a residual sound detector. The noise controller is configured to produce a control sound signal for canceling out noise. The control sound output component is configured to output a control sound based on the control sound signal produced by the noise controller. The residual sound detector is configured to detect a residual sound produced by superposition of noise and the control sound outputted from the control sound output component. The control sound output component and the residual sound detector are housed in the shell. The control sound output component and the residual sound detector are away from a rear face of the seat.

Abstract: A noise reduction device, including a microphone for detecting noise, a noise controller for reversing the phase of noise detected by the microphone based on information outputted from the microphone, and a speaker for outputting sound based on information outputted from the noise controller, is arranged at a seat surrounded by a shell portion having a cavity, wherein a speaker is disposed in the cavity of the shell portion.

Abstract: A noise control device includes the following structural elements. A signal memory records both of a noise signal supplied from a noise microphone and an error signal supplied from an error microphone. A filter coefficient calculator calculates a fixed filter coefficient of a control filter by using data recorded in the signal memory. A filter coefficient renewing section renews, at a given timing, a filter coefficient set at a fixed filter in a control filter to a filter coefficient read out from the filter coefficient calculator.

Abstract: It includes a microphone for detecting noise emitted from a noise source, a noise controller for generating control sound signal to reduce noise detected by the microphone based on information from the microphone, and a speaker for outputting control sound based on control sound signal from the noise controller, wherein a plurality of microphones and speakers are arranged for each seat, and a plurality of microphones are arranged in higher density for each seat in a specific direction.

Abstract: A noise reduction device including a noise detection microphone including a high-frequency noise detection microphone and a low-frequency noise detection microphone for respectively detecting a high-frequency noise and a low-frequency noise generated from a noise source; a noise control unit for generating a control sound signal for cancelling a noise detected by the noise detection microphone in a control center of control space; and a loudspeaker for outputting a control sound based on the control sound signal from the noise controlling unit. The high-frequency noise microphone is disposed in a vicinity of a head portion of a user in a state in which directivity in an opposite direction with respect to the control center is added, and the low-frequency noise detection microphone is disposed outside of a sound-insulating wall.

Abstract: A noise reduction device of the present invention comprises a control filter unit for generating a control sound signal to cancel out a noise, a control speaker for outputting a control sound according to the control sound signal from the control filter unit, an error microphone for detecting a residual sound by superimposing the noise upon the control sound output from the control speaker, and an obstacle detector for detecting an obstacle around the error microphone, wherein the control filter unit generates the control sound signal according to data from the error microphone and the obstacle detector.

Abstract: A noise reduction device is disclosed, in which noise reduction device, a controlling sound generator outputs a white noise generated by a white-noise generator, and this white noise is sensed by an error sensor for identifying an acoustic transmission function covering a path from the controlling sound generator to the error sensor. At this time, an identification controller prompts the white noise generator to generate a white noise for identifying the acoustic transmission function provided that an ambient noise level sensed by the error sensor is not greater than a given threshold.

Abstract: In a noise reduction apparatus for controlling noise up to a predetermined upper limited frequency, a distance from a noise source to control point X is made larger than a distance obtained by subtracting a one-half wavelength from a distance, obtained by adding up a distance from the noise source to a noise detecting microphone, a distance corresponding to time as a sum of respective delay time of the noise detecting microphone, a noise controller, and a control speaker, and a distance from the control speaker to control point X, where one wavelength is a period corresponding to the upper limited frequency.

Abstract: A noise reduction device of the present invention comprises a control filter unit for generating a control sound signal to cancel out a noise, a control speaker for outputting a control sound according to the control sound signal from the control filter unit, an error microphone for detecting a residual sound by superimposing the noise upon the control sound output from the control speaker, and an obstacle detector for detecting an obstacle around the error microphone, wherein the control filter unit generates the control sound signal according to data from the error microphone and the obstacle detector.

Abstract: A noise reduction device is disclosed, in which noise reduction device, a controlling sound generator outputs a white noise generated by a white-noise generator, and this white noise is sensed by an error sensor for identifying an acoustic transmission function covering a path from the controlling sound generator to the error sensor. At this time, an identification controller prompts the white noise generator to generate a white noise for identifying the acoustic transmission function provided that an ambient noise level sensed by the error sensor is not greater than a given threshold.

Abstract: In a noise reduction apparatus for controlling noise up to a predetermined upper limited frequency, a distance from a noise source to control point X is made larger than a distance obtained by subtracting a one-half wavelength from a distance, obtained by adding up a distance from the noise source to a noise detecting microphone, a distance corresponding to time as a sum of respective delay time of the noise detecting microphone, a noise controller, and a control speaker, and a distance from the control speaker to control point X, where one wavelength is a period corresponding to the upper limited frequency.

Abstract: A noise control device includes the following structural elements. A signal memory records both of a noise signal supplied from a noise microphone and an error signal supplied from an error microphone. A filter coefficient calculator calculates a fixed filter coefficient of a control filter by using data recorded in the signal memory. A filter coefficient renewing section renews, at a given timing, a filter coefficient set at a fixed filter in a control filter to a filter coefficient read out from the filter coefficient calculator.

Abstract: A noise reduction device, including a microphone for detecting noise, a noise controller for reversing the phase of noise detected by the microphone based on information outputted from the microphone, and a speaker for outputting sound based on information outputted from the noise controller, is arranged at a seat surrounded by a shell portion having a cavity, wherein a speaker is disposed in the cavity of the shell portion.

Abstract: It includes a microphone for detecting noise emitted from a noise source, a noise controller for generating control sound signal to reduce noise detected by the microphone based on information from the microphone, and a speaker for outputting control sound based on control sound signal from the noise controller, wherein a plurality of microphones and speakers are arranged for each seat, and a plurality of microphones are arranged in higher density for each seat in a specific direction.

Abstract: A noise reduction device including a noise detection microphone including a high-frequency noise detection microphone and a low-frequency noise detection microphone for respectively detecting a high-frequency noise and a low-frequency noise generated from a noise source; a noise control unit for generating a control sound signal for cancelling a noise detected by the noise detection microphone in a control center of control space; and a loudspeaker for outputting a control sound based on the control sound signal from the noise controlling unit. The high-frequency noise microphone is disposed in a vicinity of a head portion of a user in a state in which directivity in an opposite direction with respect to the control center is added, and the low-frequency noise detection microphone is disposed outside of a sound-insulating wall.