Abstract: According to one embodiment, a vibration power generator includes a housing, an elastic member, a mover, and a coil. The elastic member is fixed to the housing. The mover is supported by the elastic member and able to vibrate in a first direction. The coil is positioned inside the mover. The mover includes a first magnet, a second magnet, a third magnet, and a first magnetic yoke. The second magnet is placed to be aligned with the first magnet in the first direction so as to repel each other. The third magnet is placed annularly with respect to the first magnet and the second magnet. The first magnetic yoke surrounds the first magnet, the second magnet and the third magnet. The coil is positioned between the third magnet, and both the first magnet and the second magnet.

Abstract: According to one embodiment, an estimating apparatus includes an insertion tube, a first sensor, a second sensor, a processing unit, an adder, and an analyzer. The insertion tube is detachably mounted midway along a coupling tube that couples an excitation source to a main unit. The first sensor is provided inside the insertion tube at a first distance from an exit of a space housing the excitation source. The second sensor is provided at a second distance from the first sensor. The processing unit performs filter processing to a first signal obtained by the first sensor. The adder adds a filtered signal and a second signal obtained by the second sensor, the first signal being the first signal having undergone filter processing by the processing unit. The analyzer analyzes a frequency of a signal obtained by the adder.

Abstract: According to one embodiment, a system for reducing interference noise of rotor and stator blades includes rotor blades, stator blades, loudspeakers, one or more reference microphones, and a controller. The rotor blades rotate about a central axis. The loudspeakers are discretely arranged on a circle that has a center positioned on the central axis. Each loudspeaker generates a control sound. The controller causes the loudspeakers to generate control sounds of a same phase and a same amplitude. The control sounds correspond to the loudspeakers. The r is selected based on a preset attenuation level concerning the interference noise, and the k, where a is a length of the rotor blades, b is a radius of the circle, r =a/b, k is an upper limit wavenumber.

Abstract: A reproducing apparatus includes, a first sensor, processing circuitry, an audio reproducing device, and an image reproducing device. The first sensor detects a current location of a user. The processing circuitry acquires a destination, determines a direction of the destination based on the current location, generates a guidance sound image and a guidance image, and determines a first output timing which is an output timing of the guidance sound image and a second output timing which is an output timing of the guidance image. The audio reproducing device reproduces the guidance sound image at the first output timing to guide the user toward the destination. The image reproducing device reproduces the guidance image at the second output timing to guide the user toward the destination.

Abstract: An acoustic inspection apparatus includes an acoustic-intensity calculating unit, a noise calculating unit, a noise removing unit and an inspecting unit. The acoustic-intensity calculating unit calculates an acoustic intensity, in which an acoustic intensity caused by hammering on an inspection target at a hammering position is canceled out, based on audio signals acquired by microphones in a symmetrical arrangement of at least one pair of microphone positions with respect to the hammering position or in a symmetrical arrangement of two hammering positions with respect to a pair of microphone positions. The noise calculating unit calculates a noise component from the calculated acoustic intensity. The noise removing unit removes the noise component from a physical quantity based on at least one of audio signals acquired at the at least one pair of microphone positions. The inspecting unit performs inspection on the hammering position based on the physical quantity.

Abstract: A reproducing apparatus includes, a first sensor, processing circuitry, an audio reproducing device, and an image reproducing device. The first sensor detects a current location of a user. The processing circuitry acquires a destination, determines a direction of the destination based on the current location, generates a guidance sound image and a guidance image, and determines a first output timing which is an output timing of the guidance sound image and a second output timing which is an output timing of the guidance image. The audio reproducing device reproduces the guidance sound image at the first output timing to guide the user toward the destination. The image reproducing device reproduces the guidance image at the second output timing to guide the user toward the destination.

Abstract: A rotor blade noise reduction system includes: a plurality of rotor blades; a plurality of first speakers disposed equidistantly on a first circumference which is opposed to one surface of a rotor blade plane; a plurality of second speakers disposed equidistantly on a second circumference which is opposed to the other surface of the rotor blade plane; at least one evaluation microphone configured to acquire noise generated from the rotating rotor blades and control sound generated from the first speakers and the second speakers; and an active sound suppression processor configured to input a plurality of first delay control signals corresponding to the first speakers, and to input a plurality of second delay control signals corresponding to the second speakers.

Abstract: According to one embodiment, a noise reduction apparatus includes a speaker, a generator and a controller. The speaker outputs control sound. The generator generates self-excited sound. The controller controls a phase and an amplitude of the control sound to reduce noise generated from a noise source, based on the control sound and the self-excited sound that is synchronized with the control sound.

Abstract: According to one embodiment, a rotating blade noise reduction device for reducing noise from a flight vehicle including rotating blades, the device includes loudspeakers, one or more reference microphones, an estimator, and a processor. The loudspeakers are arranged coaxially in a circumferential form for each of the rotating blades. The reference microphones acquire noise generated from the rotating blades and control sounds generated from the loudspeakers. The estimator estimates angular frequencies of the rotating blades. The processor generates control signals so as to reduce sound pressures at the reference microphones, delays the control signals by time delays corresponding to the loudspeakers dependent on installation angles between the loudspeakers arranged coaxially in a circumferential form from a circle center, the angular frequencies estimated, and a number of the loudspeakers, and inputs the control signals to the loudspeakers.

Abstract: According to one embodiment, a rotor-stator blade interference noise reduction system includes a plurality of rotor blades rotating around a center axis, a plurality of stator blades facing the plurality of rotor blades and being equal in number to the plurality of rotor blades, a plurality of speakers installed approximately along a rotor blade plane defined by the plurality of rotor blades rotating and generating control sound, and an evaluation microphone, in which a distance from the evaluation microphone to one of the plurality of speakers, a distance from the evaluation microphone to another of the plurality of speakers, and a distance from the evaluation microphone to the center axis, are approximately equal.

Abstract: A rotor blade noise reduction system includes: a plurality of rotor blades; a plurality of first speakers disposed equidistantly on a first circumference which is opposed to one surface of a rotor blade plane; a plurality of second speakers disposed equidistantly on a second circumference which is opposed to the other surface of the rotor blade plane; at least one evaluation microphone configured to acquire noise generated from the rotating rotor blades and control sound generated from the first speakers and the second speakers; and an active sound suppression processor configured to input a plurality of first delay control signals corresponding to the first speakers, and to input a plurality of second delay control signals corresponding to the second speakers.

Abstract: According to one embodiment, a noise reduction apparatus includes a first control sound source, a first current detection unit, a second control sound source, a second current detection unit, and an adjustment unit. The first control sound source generates a first control sound for reducing noise from a noise source. The first current detection unit detects a first current flowing from the first control sound source upon receiving the noise from the noise source. The second control sound source is provided at a position different from a position of the first control sound source and generates a second control sound for reducing the noise from the noise source. The second current detection unit detects a second current flowing from the second control sound source upon receiving the noise from the noise source. The adjustment unit adjusts the first control sound and the second control sound so as to make the first current and the second current satisfy a predetermined condition.

Abstract: According to one embodiment, a diagnostic device includes a hammering sound signal acquisition unit, a frequency characteristic conversion unit, and an abnormality determination unit. The hammering sound signal acquisition unit acquires an i-th hammering sound signal representing a hammering sound with respect to striking applied to an i-th struck position among a plurality of struck positions of an inspection target, and a j-th hammering sound signal representing a hammering sound with respect to striking applied to a j-th struck position among the plurality of struck positions of the inspection target. The frequency characteristic conversion unit respectively converts the i-th hammering sound signal and the j-th hammering sound signal acquired by the hammering sound signal acquisition unit into an i-th frequency characteristic and a j-th frequency characteristic.

Abstract: According to one embodiment, a noise reduction apparatus includes a speaker, a generator and a controller. The speaker outputs control sound. The generator generates self-excited sound. The controller controls a phase and an amplitude of the control sound to reduce noise generated from a noise source, based on the control sound and the self-excited sound that is synchronized with the control sound.

Abstract: According to one embodiment, a rotor-stator blade interference noise reduction system includes a plurality of rotor blades rotating around a center axis, a plurality of stator blades facing the plurality of rotor blades and being equal in number to the plurality of rotor blades, a plurality of speakers installed approximately along a rotor blade plane defined by the plurality of rotor blades rotating and generating control sound, and an evaluation microphone, in which a distance from the evaluation microphone to one of the plurality of speakers, a distance from the evaluation microphone to another of the plurality of speakers, and a distance from the evaluation microphone to the center axis, are approximately equal.

Abstract: According to one embodiment, a noise reduction apparatus includes a first control sound source, a first current detection unit, a second control sound source, a second current detection unit, and an adjustment unit. The first control sound source generates a first control sound for reducing noise from a noise source. The first current detection unit detects a first current flowing from the first control sound source upon receiving the noise from the noise source. The second control sound source is provided at a position different from a position of the first control sound source and generates a second control sound for reducing the noise from the noise source. The second current detection unit detects a second current flowing from the second control sound source upon receiving the noise from the noise source. The adjustment unit adjusts the first control sound and the second control sound so as to make the first current and the second current satisfy a predetermined condition.

Abstract: A sound generating device according to an embodiment includes a sound tube and a sound generator. The sound tube is to be held between a tragus and an antitragus. The sound generator is disposed inside the sound tube.

Abstract: According to one embodiment, a noise reduction device includes speakers, microphones, and a processing circuit. The speakers are arranged around a rotor and emit control sound based on control signals. The microphones are arranged around the rotor and convert the control sound and noise emitted by the rotor into microphone signals. The processing circuit generates the control signals for reducing acoustic power in positions of the microphones, based on the microphone signals, rotation speed of the rotor, and a phase of noise that reaches the microphones from the rotor.

Abstract: According to one embodiment, a speaker system includes a plurality of filters and a plurality of speakers. The filters filter a first signal to generate a plurality of second signals. The speakers convert the second signals into respective sound waves. Each speaker has a diaphragm and a vibration source installed in the diaphragm. Diaphragms of the speakers have at least two different shapes. Respective transfer characteristics of the diaphragms are different from each other. Each filter corresponding to the respective transfer characteristics is set such that a transfer characteristic of a synthetic sound wave of the respective sound waves approaches a target transfer characteristic.

Abstract: An acoustic inspection apparatus includes an acoustic-intensity calculating unit, a noise calculating unit, a noise removing unit and an inspecting unit. The acoustic-intensity calculating unit calculates an acoustic intensity, in which an acoustic intensity caused by hammering on an inspection target at a hammering position is canceled out, based on audio signals acquired by microphones in a symmetrical arrangement of at least one pair of microphone positions with respect to the hammering position or in a symmetrical arrangement of two hammering positions with respect to a pair of microphone positions. The noise calculating unit calculates a noise component from the calculated acoustic intensity. The noise removing unit removes the noise component from a physical quantity based on at least one of audio signals acquired at the at least one pair of microphone positions. The inspecting unit performs inspection on the hammering position based on the physical quantity.