Abstract: An active noise reduction system for reducing the acoustic noise generated by a hard disk drive or generated external of a hard disk drive. The active noise reduction system is integrated into the hard disk drive and produces an acoustic waveform that is 180 degrees out-of-phase with the acoustic noise being generated, for example, by the spindle motor and VCM. The acoustic noise is received directly through a microphone or indirectly through the read/write head, spindle motor driver, or VCM driver. The acoustic noise is processed by electronics and the noise canceling waveform is either retrieved from the hard disk drive's memory, disk, or generated by the electronics. The noise canceling waveform is then broadcasted through one or more transducers that are integrated in the hard disk drive.

Abstract: An improved active noise reduction system which has a transducer, an electro-acoustic sensing means including adjacent to the transducer, an attenuation means with electro-acoustic sensing means to attenuate selected sound frequencies, said system utilizing both feed forward control means and feedback control means comprising a heteronomous electronic controller with algorithmic transfer function and said controller being individually operable.

Abstract: The present invention relates to a soundproof panel, and in particular to a smart panel for decreasing a noise in a wide band. The smart panel according to the present invention includes a board structure for decreasing a noise of an audible frequency band, a sound absorption member attached to one surface of the board structure for decreasing the noise of an audible frequency band, and a piezoelectric unit attached to the board structure for decreasing the noise when the same audible frequency as the resonance frequency of the smart panel is propagated for thereby maximizing the insertion loss in the resonance frequency of the smart panel.

Abstract: A device for use in an audio signal processing system, the device having at least one operating member for processing an audio signal; and a vibration transmission circuit connected to the operating member to distribute undesired vibration in controlled manner.

Abstract: A modular air induction assembly comprises an air induction body, an air filter operatively attached to the air induction body, and a speaker operatively attached to the air induction body. The modular air induction assembly is then installed into the air induction system of a vehicle during production. The air induction body may also comprise a first portion and a second portion that permits service of the assembly following initial vehicle installation.

Abstract: An adapter for reducing echo and noise in internet telephony for use with personal computers. The device employs analog circuitry to provide signal filters and delay which act together to reduce line induced echo and background noise, thus providing a clear voice communication channel. The device is readily inserted between standard microphones and speakers employed in the personal computer.

Abstract: An improved personal noise attenuation system which attenuates both tonal and broadband sound and which includes a spatially adjustable acousto-electric sensor and attenuation means including both feedback and feed forward components so as to provide a heteronomous attenuation and more complete active noise attenuation and the adjustable acousto-electric sensor is moved to exploit the changing physical characteristics of spatial silent zones in different noise fields.

Abstract: The invention relates to a method and an equipment for attenuating sound in a duct. Sound propagating in a duct is detected by means of a detector (2) and attenuated by using two successive monopole elements (3, 4) in such a way that both elements function as a dipole approximation and the elements are also used to approximatively produce the monopole radiation needed. A dipole control signal is fed to both elements (3, 4) at a phase shift which is 180° between the two elements. In addition, a monopole control signal is fed to the same elements (3, 4), only this time cophasally. Total volume velocities produced by the two elements (3, 4) are combinations of the portions obtained from the monopole and dipole sources.

Abstract: An air induction system for an internal combustion engine utilizes localized heat generation to produce a desired acoustic profile that attenuates noise propagated through the air induction system. The noise propagated through the air induction system varies over time to form a variable noise profile. A heat generating mechanism, such as a laser array or electric spark generator, produces a predetermined amount of heat within a localized area adjacent to an inlet to the air duct housing. The predetermined amount of heat is an amount of heat sufficient to produce a desired acoustic energy as a result of rapid air expansion at the localized area. A controller varies the predetermined amount of heat over time to produce a desired acoustic profile that cancels the variable noise profile.

Abstract: A device for determining and characterizing noises generated by masticating food has an enclosure and a mastication device arranged in the enclosure. One or more first reception microphones for airborne sound are arranged in the enclosure. The enclosure is advantageously a dummy head for audio recording. Preferably, two such first reception microphones are arranged in the enclosure. Two second reception microphones for sound conducted by solid material, simulating bone conduction, may be provided in order to create a sound as near-natural as possible.

Abstract: A sound source device is connected to one end of a pipe arrangement to supply sound into the pipe arrangement. Regenerators are installed to the pipe arrangement. Each regenerator serves as an energy converter that converts energy of an acoustic wave of the sound, which is propagated in the pipe arrangement, into another form of energy. Acoustic wave amplifier/attenuator apparatuses are provided in the pipe arrangement at a corresponding location between the sound source device and a corresponding one of the regenerators. Each acoustic wave amplifier/attenuator apparatus uses thermoacoustic effect to amplify or attenuate the acoustic wave and includes a cold heat exchanger, a hot heat exchanger and a stack that is held between the cold heat exchanger and the hot heat exchanger.

Abstract: A vibration control system for an engine or transmission cover on a motor vehicle to absorb and dissipate gear or chain-induced vibration uses a piezoelectric strain actuator with a passive resonant control system to absorb and dissipate vibration at a fixed resonance frequency of transmission and engine timing covers. Another embodiment uses an open-loop active control system, based on signals already existing on-board in the engine controller and a control map of phase, amplitude and frequency. Still another embodiment employs a hybrid system, combining open- and closed-loop control.

Abstract: A noise measurement apparatus capable of performing accurate measurement stably without fluctuation and a noise measuring cable to be used for the apparatus are provided. The noise measuring cable, which connects a measurement object to a connector electrically, includes an insulation tube and a conductive wire mesh covering the insulation tube. Extended portions formed by extending the wire mesh from both the end portions of the insulation tube to narrow are formed. The tip of the extended portion on one side is connected to a connector and resistor side, and a clip which is freely attached to and detached from the measurement object is connected to the tip of the extended portion on the other side.

Abstract: A noise reduction apparatus for reducing noise propagated toward a space 5 on one side of a wall 4 from an external noise source on the other side of the wall 4. The noise reduction apparatus includes a control sound source 1, an error detector 2, and a control section 3. The control sound source 1 is placed on the wall 4 so as to block a noise propagation path. Also, the control sound source radiates a sound into the space 5. The error detector 2 detects the sound propagated from the noise source through the control sound source 1. The control section 3 causes the control sound source 1 to radiate a sound so as to minimize the sound to be detected by the error detector 2 based on the detection results of the error detector 2.

Abstract: An air introduction system (10) includes an active noise control system (22) having an environmentally protected microphone (24). A microphone support structure (26) defines a louvered cage (38) over a microphone reception cavity (40). The microphone (24) is mounted to a circuit board (42) which fits within the microphone reception cavity (40). A cover (42) fits into the cavity (40) to encase the microphone (24) therein. An open cell foam (60) surround the microphone (24) and a waterproof material (58) encases the foam (60). The waterproof material (58) includes an excess of material such that waterproof material provides for internal air expansion and contraction. By locating the foam (60) between the microphone (24) and the waterproof material (58) improved transmission of acoustic waves is provided which thereby maintains microphone sensitivity.

Abstract: A sound masking system according to the invention is disclosed in which one or more sound masking loudspeaker assemblies are coupled to one or more electronic sound masking signal generators. The loudspeaker assemblies in the system of the invention have a low directivity index and preferably emit an acoustic sound masking signal that has a sound masking spectrum specifically designed to provide superior sound masking in an open plan office. Each of the plurality of loudspeaker assemblies is oriented to provide the acoustic sound masking signal in a direct path into the predetermined area in which masking sound is needed. In addition, the sound masking system of the invention can include a remote control function by which a user can select from a plurality of stored sets of information for providing from a recipient loudspeaker assembly an acoustic sound masking signal having a selected sound masking spectrum.

Abstract: A multi-channel active noise control system and method of reducing tonal noise emanating from a tonal noise source are disclosed. The system may include an adaptive controller, a plurality of loudspeakers driven by the loudspeaker, one or more microphones for generating one or more error signals to feedback to the adaptive controller and optionally a reference signal source to provide the adaptive controller with frequency information associated with the tonal noise source. The system and method of the present invention are applicable to any tonal noise source, including but not limited to axial fans.

Abstract: A built-in microphone device for use in an apparatus having a mechanism section generating internal noise inside a housing of the apparatus includes a main microphone for picking up an external sound; a noise reference microphone for picking up the internal noise; an adaptive filter member for generating a control audio signal based on an output signal from the noise reference microphone using a filter coefficient; a signal subtraction section for subtracting the control audio signal generated by the adaptive filter member from an output signal from the main microphone to generate a subtraction result; and a filter coefficient update control section for receiving an operation signal generated at the time of an operation of the mechanism section, and in response to the operation signal, updating the filter coefficient of the adaptive filter member based on the subtraction result generated by the signal subtraction section and an output signal from the noise reference microphone.

Abstract: A resonator for noise damping in a sound-conducting tubular channel (2) is provided with an actively controllable sound generator (4) which is arranged in a resonator chamber (12) to generate interference noise (16) to be superimposed on the tubular channel noise. The resonator chamber (12) is connected via a sound-transmitting opening in a tube wall (3) of the tubular channel (2) to the inside of the tubular channel. A measurement signal from a sound sensor (8) arranged in the tubular channel (2), containing information about the sound spectrum in the channel, is connected amplified, to the sound generator (4) with the same frequency and with inverse phase position. To amplify the active suppression of the sound level by the resonator with a resonator of the smallest possible overall size, the sound-transmitting opening in the tube wall is constructed as a peripheral annular gap in the tube wall.

Abstract: A noise-suppressing receiver is provided. A noise pick-up and a receiver are fixed within a cylinder-like body. An insulation layer is set between the noise pick-up and the receiver. The insulation layer divides the cylinder-like body into a receiver module and a noise-collecting module. A reticulate cover is provided at an end of the cylinder-like body, and a front cap is provided on the other end. A circuit device is added onto the inner side of the front cap described above. The invention has the stronger capability of attenuating environmental noise and the good effect of suppressing noise, because of its unique structure and the corresponding circuit device.

Abstract: An echo sounder includes front and rear masses and a layered product of piezoelectric ceramics sandwiched therebetween, and a hollow space is formed in the front mass for defining a bending vibratory plate portion; a ring-shaped piezoelectric vibrator is accommodated in the hollow space, and has flat major surface or an outer side surface held in contact with the front mass without being fixed to the bending vibratory plate; while the layered product of piezoelectric ceramics gives rise to bending vibrations in the bending vibratory plate, the ring-shaped piezoelectric vibrator is driven for vibrations at the resonant frequency so that an acoustic wave with a large amplitude is radiated from the echo sounder; the bending vibratory plate and ring-shaped piezoelectric vibrator are independently designed so that the echo sounder achieves a high acoustic radiation efficiency without sacrifice of high withstand water pressure.

Abstract: The present invention relates to a smart foam for active noise control in a duct and a device equipped with the same. In particular, the smart foam for the active noise control in a duct according to the present invention comprises: an external ring (52) made out of an elastic porous synthetic resin foam material of a certain length; an internal ring (54) made out of an elastic porous synthetic resin foam to be inserted into the said external ring (52); a ring type PVDF film (60) to be interposed between the said external ring (52) and the internal ring (54) for the radiation of sounds, on the outer and inner surfaces of which film conductive material layers are plated; and lead wires (64) connecting the conductive material layers (62) on the outer and inner surfaces of the said PVDF film (60) to different electrodes and conveying voltages thereto in order to enable the PVDF film (60) to radiate sounds.

Abstract: A flow tube for an induction system with a turbo charger includes a first tube half and a second tube half with a noise attenuation plate positioned between the halves. The noise attenuation plate includes a plurality of holes having varying diameter and depths. The first tube half, the second tube half, and the noise attenuation plate are integrally formed as a single piece during an injection molding process. The noise attenuation plate is folding along a first living hinge to overlap one of the first or second tube halves. The other of the first or second tube halves is folded along a second living hinge to overlap the noise attenuation plate forming a flow tube that defines a flow path. The noise attenuation plate is thus positioned in the flow path. When acoustic energy created by the turbo charger encounters the noise attenuation plate, the change in impedance results in acoustic reflections back toward the turbo charger.

Abstract: The device for the active sound attenuation of a sound signal propagated in a duct comprises: at least first sensor means for a first sound signal, attenuation actuating means supplying an active sound attenuation signal in response to a selected control signal, an electronic control means generating the active sound attenuation signal for the actuating means. The first sensor means and the actuating means are arranged completely inside the duct opposite one another and at a selected distance from the casing of the duct, the axis of symmetry of the radiation of the actuating means and the axis of symmetry of the first sensor means are substantially parallel to the direction of propagation of the sound signal in the duct, and the actuating means are arranged upstream of the first sensor means in the direction of propagation of the sound signal in the duct.

Abstract: This invention concerns environmental noise monitoring, and more particularly a system and method for environmental noise monitoring. The environmental noise monitoring system comprises three or more sound level transducers arranged apart from each other in an environment containing one or more noise sources. Each transducer is arranged to pick up sounds arriving from all directions and to transduce the sounds into electrical signals. The sound level and direction measuring equipment includes signal samplers connected to respective transducers to receive electrical signals representing environmental sounds and to sample the electrical signals. A computer processor is further provided to perform cross correlation calculations to generate a cross correlation function for each pair of sampled signals.

Abstract: A sound reinforcement system (1) comprises at least one microphone (2), adaptive echo compensation (EC) means (4) coupled to said microphone (2) for generating a microphone signal, and one or more loudspeakers (3) coupled to the EC means (4). In addition it comprises a dynamic echo suppressor (DES 7) coupled between the adaptive EC means (4) and said at least one loudspeaker (3) for suppressing remaining echoes by using a time delay between the amplitudes of a microphones signal frequency component and the same remaining echo frequency component.

Abstract: An individual-type or combined-type of high performance noise-canceling pickup with front and rear sound inlets that are roughly toward the same direction or perpendicular to each other is provided to be composed of a plurality of noise-canceling sensors. The noise-canceling performance of that pickup is much better than that of only individual-type noise canceling pickup with the sound inlets on the front wall of the front cover and the rear wall of the rear cover. Even in the extremely bad circumstances of high volume of noise, high signal/noise ratio can be still maintained so that voice is distinct.

Abstract: The present invention relates to a smart foam for active noise control in a duct and a device equipped with the same. In particular, the smart foam for the active noise control in a duct according to the present invention comprises: an external ring (52) made out of an elastic porous synthetic resin foam material of a certain length; an internal ring (54) made out of an elastic porous synthetic resin foam to be inserted into the said external ring (52); a ring type PVDF film (60) to be interposed between the said external ring (52) and the internal ring (54) for the radiation of sounds, on the outer and inner surfaces of which film conductive material layers are plated; and lead wires (64) connecting the conductive material layers (62) on the outer and inner surfaces of the said PVDF film (60) to different electrodes and conveying voltages thereto in order to enable the PVDF film (60) to radiate sounds.

Abstract: A noise suppressor for reducing propagation of a floor impact noise generated in an upper story to a lower story in a multi-storied building is disclosed. A reference sensor set at a position between a floor of the upper story and a ceiling of the lower story detects a floor impact noise generated in the upper story and converts the noise to an electric signal. This signal is computed and processed by a control unit and transmitted to a speaker located at a position lower than the reference sensor. The speaker emitts a sound wave interfering the floor impact noise to eliminate the noise. The noise not having been suppressed is detected by an error sensor and processed together with the noise detected by the reference sensor by the control unit, thus a sound wave to be emitted from the speaker is corrected appropriately.

Abstract: A modular air induction assembly comprises an air induction body, an air filter operatively attached to the air induction body, and a speaker operatively attached to the air induction body. The modular air induction assembly is then installed into the air induction system of a vehicle during production. The air induction body may also comprise a first portion and a second portion that permits service of the assembly following initial vehicle installation.

Abstract: In a device having a sound source within an enclosure and a first microphone for picking up sounds outside the enclosure, a system for improving acoustic separation between the sound source and first microphone comprising an additional microphone located approximately equidistant from the sound as the first microphone for picking up sounds within the enclosure, and a circuit connected to the first microphone and the additional microphone for subtracting the sounds within the enclosure from the sounds outside the enclosure.

Abstract: The present invention combines audio compression and feedback cancellation in an audio system such as a hearing aid. The feedback cancellation element of the present invention uses one or more filters to model the feedback path of the system and thereby subtract the expected feedback from the audio input signal before hearing aid processing occurs. The hearing aid processing includes audio compression, for example multiband compression. The operation of the audio compression element may be responsive to information gleaned from the feedback cancellation element, the feedback cancellation may be responsive to information gleaned from the compression element, or both.

Abstract: An active noise attenuation system (10) comprises a speaker (26) in communication with a flow body (78). The speaker (26) emits an output for attenuating noise from the flow body (78). A control unit (31) communicates with the speaker (26) and controls the output. A housing (14) has one volume (18) acting as a liquid storage chamber and another volume (22) acting as a speaker chamber.

Abstract: A space 4 constituted by a sound absorption panel section 1 and active sound absorption control system section 2 between the inner and outer walls of a nacelle forming an engine intake/exhaust duct is utilized as an acoustic resonance field and as a sound absorption field by sticking a porous sound absorption material 14 onto the inside wall surface of the space. The panel section 1 defines a sound absorption space by means of surface plate 6 made of a perforated plate and wire mesh materials plate, panel construction side plate 9 and back sheet plate 13 having porous sound absorption material stuck thereon; and a movement-controlled reflective plate 8, that is capable of movement/rotation control with respect to said perforated plate, is provided within this sound absorption space.

Abstract: A reactive sound attenuator which includes a sensor for detecting a sound parameter in a space, e.g. a duct, consists of a signal amplifier that is used to amplify a detected signal, an electroacoustic transducer and a cavity with at least one membrane. The membrane, which is capable of moving in a vibratory manner, is part of a wall of a space, e.g. a duct wall. A sensor, which is disposed in the immediate vicinity of, in or on the membrane, detects the vibrations of the membrane. The sensor's signal, which is amplified and inverted by the amplifier, controls the membrane vibration via the electroacoustic transducer.

Abstract: An electrostatic transducer with a tubular housing in which a planar transducer membrane is arranged, whereby the transducer membrane is arranged at an angle other than 0° to the cross-section of the housing. Due to the angular arrangement of the transducer membrane to the cross-section of the housing, the transducer membrane is arranged to the ear drum in an anti-parallel fashion, which results in a minimization of the resonances inside the ear passage. Apart from that the angular arrangement of the membrane to the cross-section of the housing causes the surface of the membrane to be raised to the cross-section of the housing, which results in higher acoustic pressures and a lower dominant resonance of the system.

Abstract: A module adapted for use in a noise reduction headset earcup has an enclosure having walls separating an interior of the enclosure from an exterior of the enclosure outside the earcup. There is a driver with a diaphragm. A port connects the interior and exterior. An acoustically resistive opening connects the interior and exterior in parallel with the port.

Abstract: An active noise control system (20) which generates via an electronic controller (22) a canceling signal(s) which are responsive to a signal from an error sensor(s) (28) to drive a speaker (30) or array of speakers. Each speaker (30) is contained within an enclosure (33) and is inversely and rigidly mounted therein. The enclosure (33) attaches to the trim panels (25) attached to the closed structure (34) and the canceling sound wave form is directed primarily toward the interior surface (36) of the trim (25). Preferably, the speaker(s) (30) are flexibly suspended with mounts (38) to the trim (25). The enclosure (33) preferably includes planar wave guide means such as escapeways (40) for initially directing the canceling sound wave form (anti-noise) in a plane substantially parallel to the surface of the trim (25).

Abstract: A configuration of providing a microphone in a duct having an air current therein, for use in an active noise reduction device for reducing noise propagating in the duct by producing sounds counteracting the noise, includes an expanded room formed by enlarging an area of a cross section of part of the duct, wherein the cross section is perpendicular to a direction of the air current, and a microphone provided in the expanded room for picking up the noise in order to produce signals for the sounds.

Abstract: The air induction system comprises an air induction body having a mouth emanating a first sound and a speaker emanating a second sound disposed about the mouth. The mouth has at least a first mouth portion and at least a second mouth portion wherein the first sound is louder at the at least first mouth portion than at the at least second mouth portion. The speaker has at least a first speaker portion and at least a second speaker portion wherein the second sound is louder at the at least first speaker portion than at the at least second speaker portion.

Abstract: An active noise insulation wall includes an active sound reduction apparatus disposed on an upper end surface of a noise insulation wall. The active sound reduction apparatus comprises a combination of an active acoustic control cell and a sound tube. The active acoustic control cell controls a coming noise such that a diffracted sound pressure component of the coming noise at the upper end surface of the noise insulation wall is actively reduced. The sound tube decreases a sound wave of a frequency different from a target frequency of the active acoustic control cell. Thus, the active noise insulation wall can effectively reduce noises including many frequency components.

Abstract: An adapter for reducing echo and noise in internet telephony for use with personal computers. The device employs analog circuitry to provide signal filters and delay which act together to reduce line induced echo and background noise, thus providing a clear voice communication channel. The device is readily inserted between standard microphones and speakers employed in the personal computer.

Abstract: The air induction system comprises an air induction body having a mouth. A speaker and microphone are both operatively connected to the air induction body. A support connects the microphone to the air induction body. The support may be rigid and extend over only a portion of the face of the speaker. The support may also be spaced a predetermined distance from the speaker face. This distance may relate to the location of the sound field emitted by the speaker. Both the speaker and microphone are in communication with a control unit. The microphone receives sound and communicates this sound to the control unit. The control unit then generates a noise attenuation sound through the speaker.

Abstract: A loudspeaker system is disclosed for active noise reduction. The loudspeaker has a substantially flat or planar diaphragm which is vibrated by an appropriate driver to generate a cancelling signal to cancel noise in the vicinity of the loudspeaker. The loudspeaker includes an input transducer such as a microphone which detects the ambient noise. The microphone is preferably incorporated in the panel structure of the loudspeaker in such a way that the ambient noise information can be captured and presented to active noise cancelling circuitry. The circuitry then provides an appropriate signal to the loudspeaker driver so that the cancelling sound source is provided by the loudspeaker. The use of flat panel loudspeaker technology has been found to provide effective noise reduction and is very appropriate for circumstances in which noise reduction is desirable, for example in aircraft, bus or vehicle seats or telephone kiosks.

Abstract: A device for determining and characterizing noises generated by masticating food has an enclosure and a mastication device arranged in the enclosure. One or more first reception microphones for airborne sound are arranged in the enclosure. The enclosure is advantageously a dummy head for audio recording. Preferably, two such first reception microphones are arranged in the enclosure. Two second reception microphones for sound conducted by solid material, simulating bone conduction, may be provided in order to create a sound as near-natural as possible.

Abstract: A speaker apparatus can ensure a large size and area of a diaphragm so as to improve reproducing capability in a low sound range and increase an output sound pressure, and can constitute a plurality of vibrating points (signal control points). An input signal Vin having a plurality of independent channels is inputted, then the signal input Vin is processed in a sound signal processing portion 30 by calculating and adding of an interference canceling signal between the signal control points, by calculating and adding of a sound interference signal for causing the interference between outputs from the signal control points in an arbitrary point, etc., so as to be inputted to transducers 20 that are attached to a single diaphragm 10. The transducer 20 transduces an electric signal into mechanical vibration. A plurality of the signal control points are generated on the single diaphragm, and each signal control point cause the single diaphragm 10 to vibrate.

Abstract: The present invention is an active-control system for attenuating noise in a duct having a fluid flow. An array of stators having a longitudinal length is positioned axially within the duct. A first array of sound sources capable of generating spinning mode sound and is positioned a distance upstream of a first plane defined by the upstream-most portion of the stators, relative to the fluid flow. The upstream distance is less than the longitudinal length of the stators. A second array of sound sources capable of generating spinning mode sound and is positioned a distance downstream of a second plane defined by the downstream-most portion of the stators, relative to the fluid flow. The downstream distance is less than the longitudinal length of the stators. A controller causes the first and second arrays of sound sources to generate sound including spinning mode sound such that it cancels a portion of the noise within the fluid flow that passes through the stators.