Abstract: Characteristics of spatial transmission from a speaker to a microphone contained in a remote controller and set in a listening area and in a non-listening area are measured. A plurality of different types of sound field control effects is calculated on the basis of the spatial transmission characteristics to predict the plurality of types of sound field control effects. The plurality of types of sound field control effects is displayed and presented to a user. The speaker is driven by using a control sound source corresponding to one sound field control effect selected from the plurality of types of sound field control effects by the user operating the remote controller to perform effective sound field control in the listening area and in the non-listening area.

Abstract: In a sheet conveying mechanism, a first bulging space and a second bulging space are provided on a downstream side and an upstream side, respectively, of a conveying path. The second bulging space has a length L1 along the conveying path. The conveying path between the first and second bunging spaces is defined to have a length L2. The lengths L1 and L2 are set to satisfy a predetermined relationship with a frequency of noise propagating through the conveying path. The sheet conveying mechanism can inexpensively reduce noise generated inside the conveying path during sheet conveyance without hindering the conveyance of the sheet.

Abstract: A sheet conveying device includes: a pair of first rollers, the first rollers being disposed to oppose circumferential surfaces thereof with each other; a pair of second rollers, the second rollers being disposed to oppose circumferential surfaces thereof with each other; a guide plate that has a sheet conveyance face for guiding a leading edge of a sheet being conveyed in a conveying direction from the pair of first rollers toward the pair of second rollers, the guide plate being formed with one or more holes; and a sound absorbing member that is disposed on a back face of the guide plate, which opposes the sheet conveyance face, the sound absorbing member absorbing a sound transmitted through the hole formed on the guide plate.

Abstract: A sheet conveying device includes: a feed unit that feeds sheets from a predetermined position; a conveying unit that conveys the sheets fed by the feed unit toward an image forming position at which images are to be formed on the respective sheets; and a registration unit that is provided at an upstream of the image forming position and positions the sheets by being bumped with the sheets conveyed by the conveying unit, wherein the feed unit and the registration unit are configured to operate so that a first timing at which a precedent sheet is bumped to the registration unit and a second timing at which a subsequent sheet is fed by the feed unit matches when a plurality of sheets are consecutively fed by the feed unit.

Abstract: An active sound muffler for reducing a sound to be reduced as emitted from a sound source located at one of the opposite sides of a sound insulating wall and diffracted and transmitted to the other side, the muffler comprises a control loudspeaker arranged at the front end or the other side of the sound insulating wall and adapted to output a control sound with a predetermined amplitude and a predetermined phase, a control microphone arranged above the sound insulating wall and adapted to gauge the sound pressure or the acoustic intensity of the sound to be reduced and that of the control sound and a control circuit for controlling the output of the control loudspeaker so as to minimize the sound pressure or the acoustic intensity, whichever appropriate, based on the outcome of gauging of the control microphone, and the control loudspeaker showing a line sound source characteristic.

Abstract: A reproduction apparatus includes an acoustic signal generator which generates an acoustic signal, first sound pressure detection points located at N points in an audible area to detect sound pressure signals, N+1 control sound wave generators each of which emits a sound wave based on the acoustic signal to generate a control sound, second sound pressure detection points located at M points in a non-audible area to detect sound pressure signals, M sound wave generators each of which emits a sound wave based on the acoustic signal to generate a main sound, and a controller to control an amplitude and a phase of each of the (N+1) control sound wave generators.

Abstract: Apparatus includes generator generating reference signal based on noise emitted from sound source, detector detecting level of reference signal and change in level, unit comparing change with threshold-value range and produce compared result, filter filtering reference signal, adaptive filter having variable filter coefficient, unit updating filter coefficient according to change of level of reference signal for obtaining an updated filter coefficient, unit stopping updating of filter coefficient in response to compared result when change falls outside threshold-value range, unit storing updated filter coefficient each time filter coefficient is updated, generator generating control signal using stored filter coefficient, unit generating control sound based on control signal, microphone detecting synthesis sound pressure of control sound and noise to produce an error signal, and unit setting stored filter coefficient to more accurate coefficient than stored filter coefficient based on error signal, and signal

Abstract: A sound reproducing apparatus includes an amplitude and phase adjusting unit that adjusts amplitude and phase of a sound signal which is supplied as an input, and outputs an adjusted sound signal; a first sound source that outputs a first sound based on the sound signal; and a second sound source that outputs a second sound based on the adjusted sound signal, and that has a different distance decay rate from the first sound source, the distance decay rate representing a ratio of attenuation of sound pressure of sound output from a sound source to a distance from the sound source; wherein the amplitude and phase adjusting unit adjusts the amplitude and the phase of the sound signal, so as to restrain a synthesis sound pressure that is a combination of a sound pressure of the first sound which is calculated based on the distance decay rate of the first sound source, and a sound pressure of the second sound which is calculated based on the distance decay rate of the second sound source, at a predetermined distan

Abstract: A three-dimension active silencer includes a measuring unit for detecting a signal relating to a sound radiated from a target sound source which is located in a closed box. A plurality of additional sound sources are arranged around the target sound source. A microphone is arranged at a predetermined position for detecting a sound power at the position. A controller is adapted to control respective amplitudes of the additional sound sources which can be different from an amplitude of the target sound source and respective phases of the additional sound sources, based on the signal detected by the measuring unit, in such a manner that the microphone detects the lowest sound power. The additional sound sources are arranged in such a manner that a position xp of the target sound source, respective relative positions di (i=1, 2, . . .

Abstract: A contents reproducing system includes a unit which acquires contents data, a specifying unit which specifies a space transfer function that reflects a state of a space in which sound data contained in the contents data is reproduced, a generating unit which generates control sound data based on the sound data contained in the contents data and the specified space transfer function, and an output unit which outputs the sound data and the control sound data to speakers which are different from each other, respectively.

Abstract: A three-dimension active silencer includes a measuring unit for detecting a signal relating to a sound radiated from a target sound source which is located in a closed box. A plurality of additional sound sources are arranged around the target sound source. A microphone is arranged at a predetermined position for detecting a sound power at the position. A controller is adapted to control respective amplitudes of the additional sound sources which can be different from an amplitude of the target sound source and respective phases of the additional sound sources, based on the signal detected by the measuring unit, in such a manner that the microphone detects the lowest sound power. The additional sound sources are arranged in such a manner that a position xp of the target sound source, respective relative positions di (i=1, 2, . . .

Abstract: An active diffracted sound control apparatus comprises a reference microphone for measuring the noise information on a noise source side of a sound insulating wall, a first error microphone for measuring the noise information on a noise receiving side of the sound insulating wall, a speaker arranged in the neighborhood of the sound insulating wall K for generating a control sound to reduce the object sound at a sound receiving point, and a control unit for controlling the output of the speaker based on the outputs of the reference microphone and the first error microphone. The control unit is operated based on a first sound transmission characteristic between the first error microphone and the second error microphone for the noise source and a second sound transmission characteristic between the first error microphone and the second error microphone for the speaker.

Abstract: An active noise controller includes a duct (2) of a stainless steel having the shape of a pipe and provided with an opening (1) at a first end thereof, and a loudspeaker (3)connected to a second end of the duct (2). The duct (2) is disposed with its opening (1) located at a distance not greater than half the wavelength of a sound produced by a sound source (4) from the sound source (4) so as to face the sound source (4). A sound produced by the vibration of the vibrating member (5) of the loudspeaker (3) travels from the second end of the duct (2) through the duct (2) to the first end of the same, and the sound is radiated toward the sound source (4). The sound radiated through the opening (1) has a frequency substantially equal to that of an unnecessary sound included in the sound produced by the sound source (4), an amplitude substantially equal to that of the unnecessary sound and a phase substantially opposite to that of the unnecessary sound.

Abstract: An active sound muffler for reducing a sound to be reduced as emitted from a sound source located at one of the opposite sides of a sound insulating wall and diffracted and transmitted to the other side, the muffler comprises a control loudspeaker arranged at the front end or the other side of the sound insulating wall and adapted to output a control sound with a predetermined amplitude and a predetermined phase, a control microphone arranged above the sound insulating wall and adapted to gauge the sound pressure or the acoustic intensity of the sound to be reduced and that of the control sound and a control circuit for controlling the output of the control loudspeaker so as to minimize the sound pressure or the acoustic intensity, whichever appropriate, based on the outcome of gauging of the control microphone, and the control loudspeaker showing a line sound source characteristic.

Abstract: An active noise controller includes a duct (2) of a stainless steel having the shape of a pipe and provided with an opening (1) at a first end thereof, and a loudspeaker (3)connected to a second end of the duct (2). The duct (2) is disposed with its opening (1) located at a distance not greater than half the wavelength of a sound produced by a sound source (4) from the sound source (4) so as to face the sound source (4). A sound produced by the vibration of the vibrating member (5) of the loudspeaker (3) travels from the second end of the duct (2) through the duct (2) to the first end of the same, and the sound is radiated toward the sound source (4). The sound radiated through the opening (1) has a frequency substantially equal to that of an unnecessary sound included in the sound produced by the sound source (4), an amplitude substantially equal to that of the unnecessary sound and a phase substantially opposite to that of the unnecessary sound.

Abstract: A speaker, serving as an additional sound source, is provided close to a noise source, two microphones are arranged on a central axis of a vibration surface of the speaker to be spaced from each other, acoustic intensity of the speaker is measured from outputs of these microphones, and an input to the speaker is controlled by a controller such that acoustic intensity, that is, acoustic power of the speaker is set to be zero or minimized.

Abstract: A device for detecting the position of a physical defect on a buried pipe includes a leak-of-fluid signal detector, a number of vibration signal detectors, and a device body and can detect the position of a site of a leak, into the ground, of a fluid running through a fluid pipe buried beneath the ground surface. The device body calculates vibration amplitudes and speeds via associated vibration signal detectors with the use of the outputs of the respective vibration signal detectors, calculates cross-correlation functions of the vibration amplitudes and speeds with the use of the vibration amplitudes and speeds and the output of the leak-of-fluid signal detector, calculates the amplitude intensity for each cross-correlation function, and generates resultant vector data representing the position of the leak-of-fluid site with the use of the vibration intensity.