Abstract: A noise reduction apparatus includes: a speaker with a speaker unit held by holding means to make it possible to mix sounds emitted from front and rear of a vibration plate of the speaker; a microphone provided in an area where the sounds emitted from the front and rear of the vibration plate of the speaker are mixed and cancelled; and means for supplying a noise reduction audio signal obtained by phase-inverting an audio signal collected by the microphone to the speaker.

Abstract: A vehicle-mounted three dimensional sound signal reproducing•silencing unit includes at least two speakers disposed for each of seats to be occupied by listeners so as to generate a three dimensional sound field space in a region inclusive of left and right external ears of each of the listeners, and three dimensional signal processing means for converting an output signal from a sound source into a three dimensional sound field signal for supplying it to each of the speakers, thereby reproducing a three dimensional sound field with rich presence for each of the seats. The unit also includes antiphase signal generating means for supplying a silencing signal to the three dimensional signal processing means, thereby silencing sounds for each of the seats without giving an effect on the other seats.

Abstract: A window for a subsonic passenger aircraft that provide maximum optical visibility while minimizing the amount of exterior acoustic noise transmitted through the windows to the passenger cabin during flight of the aircraft includes at least one substantially transparent window pane having the shape of an ellipse. The ellipse has a major axis and a minor axis, and the major axis is about twice as long as the minor axis and is disposed generally perpendicular to the direction of flight of the aircraft. In one exemplary embodiment, the window has a height of about 20 inches and a transparent area of about 141 square inches, and includes a pair of substantially similar window panes disposed in a parallel, spaced-apart relationship circumscribed by a mounting bezel. A plurality of the windows are each mounted with the bezels in spaced-apart rows in each of the opposite sidewalls of the aircraft fuselage.

Abstract: A control characteristics changing unit reads, from an EEPROM, various control parameters in an ANC electronic controller, which correspond to specification information acquired from ECUs. The control characteristics changing unit then outputs control parameters, depending on changed specification information among the read control parameters, as change signals Sm1 through Sm6 to a basic signal generating unit, reference signal generating units, filter coefficient updating units, corrective signal generating units, switches, and variable-gain amplifiers, respectively.

Abstract: A subtractor subtracts an echo canceling signal (?·y1(n?1)) from a canceling error signal (e(n)) to estimate the resonant noise (d(n)) to be silenced at a position of a microphone, and outputs a first basic signal (x1(n)) representing the estimated resonant noise d(n) as an input signal supplied to a controller. In the controller, a delay filter generates a second basic signal (x?(n)) by delaying the first basic signal (x1(n)) by a time value (Z?n) The controller generates a control signal (x(n)) based on the first basic signal (x(n)) and the second basic signal (x?(n)).

Abstract: A subtractor subtracts an echo canceling signal ?·yl(n?1) from a canceling error signal e(n) to estimate a residual noise to be silenced at the position of a microphone, and outputs a first basic signal x1(n) representing the residual noise. A first control circuit section generates a first control signal y1(n) based on the first basic signal x1(n) and a second basic signal x2(n) that is generated by delaying the first basic signal x1(n) by a time Z?n. A second circuit section generates a second control signal y2(n) based on the first basic signal x1(n) and an engine rotation signal.

Abstract: An audio system and method for enhancing sounds coming from the exhaust from an internal combustion engine of an operating vehicle, and optionally from other components of the vehicle including the engine compartment, into the passenger compartment of the vehicle, by using one or more microphones located close to one or more components and processing the signal(s) and sending them directly or indirectly to at least one speaker located in the passenger compartment or to at least one set of headphones is disclosed.

Abstract: An active noise control system cancels vibration and noise based on an output from an adaptive notch filter. When the difference between a current engine pulse value input to the adaptive notch filter and a past engine pulse value within a predetermined time period exceeds a predetermined level, an engine pulse monitor turns off a switch to stop the output from the adaptive notch filter. As a result, when there is a sudden change in the engine rpm, the output from the adaptive notch filter is stopped before the renewal speed of the adaptive notch filter coefficient becomes too fast to follow and the coefficient diverges, to prevent generation of abnormal sound. With this active noise control system, the user will not hear any abnormal sound from the adaptive notch filter even when there is a sudden change in the engine pulse.

Abstract: Road noise is reduced without locally storing noise spectrum patterns for determination or without detecting the present position of a vehicle from the device. An in-vehicle hands-free device causes a cellular phone to detect the present position of the vehicle and transmit the position to a server. The server determines a noise spectrum pattern corresponding to the road surface on which the vehicle is presently running. The noise spectrum pattern is based on the present position of the vehicle received from the in-vehicle hands-free device and road information. The server transmits the noise spectrum pattern to the in-vehicle hands-free device whereupon a noise canceling signal is superimposed on a received signal. The noise canceling signal is based on an inverted noise spectrum pattern that is obtained by inverting the phase of the noise spectrum pattern. The resulting composite signal is output from a speaker.

Abstract: When the frequency of an engine rotation signal reaches a predetermined frequency, a comparator of a switching unit outputs a switching control signal to selectors and a filter coefficient updater. Based on the switching control signal, the selector switches from a connection between one memory and a corrector to a connection between another memory and the corrector, thereby changing the transfer characteristics C?rr of the corrector from C?11 to C?10. Based on the switching control signal, the selector switches from a connection between one ADC and a filter coefficient updater to the connection between another ADC and the filter coefficient updater, thereby supplying the filter coefficient updater with an error signal, rather than an error signal.

Abstract: An adaptive noise control system is deployed in a box-like structure positioned within the transfer path along which the noise is being transmitted from the source of the generated noise to the receiver of the noise in the passenger compartment of an automobile. The adaptive noise control system is can be deployed in the dual bulkhead of the vehicle dashboard to provide a constrained volume within which engine noise can be controlled. The adaptive control system generates a mathematical model of the noise to be controlled in response to the acoustic environment identified by sensors placed within the engine compartment. Sensors in the passenger compartment define the effectiveness of the noise control system. The controller is operable to update the mathematical model in response to the changes in the acoustic environment, thus providing the appropriate acoustic response within the dual bulkhead plenum for control of noise along the transfer path.

Abstract: A noise control system is directed to the path along which the noise is transmitted from the source of the noise being generated to the receiver of the noise in the passenger compartment of an automotive vehicle. The noise control system is deployed in a box structure, such as the dual bulkhead of the dashboard of the vehicle, to provide a constrained volume within which engine noise can be controlled. The dual bulkhead plenum houses an active noise control apparatus, such as a speaker or a vibrating device, between the bulkheads to be operable with a control algorithm to generate sound that can control the noise or vibrations generated by the engine. The plenum can also be treated with passive noise control materials, such as viscoelastic damping materials, acoustical foam or heavy vinyl barrier and foam to block airborne sound and vibrations, in addition to the active noise control.

Abstract: An active noise canceller outputs a noise pattern learning request signal to a hard disk drive causing the hard disk drive to perform a predetermined operation, receives noise at this moment through a sound-receiving unit, and stores, in a nonvolatile memory unit, a relationship between the noise and a head operation data signal output from the hard disk drive. Based on the operation data signal outputted from the hard disk drive, the active noise canceller generates a noise-canceling sound while making a reference to the above relationship stored in the nonvolatile memory unit. Therefore, the signal processing needs a low degree of response for operating the noise-canceling sound.

Abstract: A control system (10) controls a variable acoustical damping device (20) disposed in a sound producing channel (5) of a vehicle engine (1). The control system includes a controller (12) and a selection device (14). The controller is coupled to the variable acoustical damping device and stores a plurality of control patterns (A. B) for different levels of acoustical damping of the acoustical damping device. The selection device outputs a selection signal to the controller so that the controller controls the variable acoustical damping device based on one of the control patterns corresponding to the selection signal.

Abstract: An active noise control system is provided which cancels a noise using a secondary noise from a speaker that is operated in accordance with an output from an adaptive controller. The system is configured such that microphone monitor interrupts a switch to thereby stop the secondary noise from being produced, when an error signal delivered by a microphone used for an adaptive computation in an LMS processing portion has the same sign for a predetermined duration. This allows the system to prevent the user from hearing an abnormal acoustic noise resulting from an abnormal operation or divergence of an adaptive filter even when the output signal from the microphone used for the adaptive computation is indicative of an abnormal level.

Abstract: A system and method of reducing noise in an enclosure is disclosed. The method includes receiving at least one reference signal; receiving pressure signals from no more than two substantially orthogonally placed pairs of acoustic sensors, where one pair of acoustic sensors is in the x-direction and one pair of acoustic sensors is in the y-direction, and where the acoustic sensors are placed in a plane which is substantially parallel and in proximity to an inner surface of the enclosure; using the pressure signals and the reference signal to generate an output signal to minimize energy density at a location of the acoustic sensors; and sending the output signal to an acoustic actuator.

Abstract: A system and method for actively damping boom noise within an enclosure such as an automobile cabin. The system comprises an acoustic wave sensor, a motion sensor, an acoustic wave actuator, a first electronic feedback loop, and a second electronic feedback loop. The enclosure defines a plurality of low-frequency acoustic modes that can be induced/excited by the enclosure cavity, by the structural vibration of a panel of the enclosure, by idle engine firings, and a combination thereof. The acoustic wave actuator is substantially collocated with the acoustic wave sensor within the enclosure. The motion sensor can be secured to a panel of the enclosure.

Abstract: A computer program product for causing a computer of an information processing device to execute processing for generating a sound that is generated by a mobile object with a plurality of tires, which moves on a predetermined surface within a virtual three-dimensional space, the computer being caused to execute the steps of: controlling the movement of the mobile object; calculating a load applied to at least one of the tires of the mobile object; controlling, on the basis of the load, a volume and a pitch of a squealing sound generated from the tires; and outputting the squealing sound. The computer is further caused to execute the steps of calculating a slip angle of at least one of the tires of the mobile object, and changing the tone of the squealing sound on the basis of the slip angle.

Abstract: A method and system for determining locations in a design of an assembly likely to result in buzz, rattle, squeak (“BSR”), and/or other noise conditions. The invention uses a finite element model to represent a design. BSR effects are predicted based upon analysis performed on multiple design models. Users may engage in real-time “what if” analyses to determine the effects of various design and component changes on noise source characteristics. Additional intelligence may be applied to limit the number of model points subject to evaluation. Displacements, contact velocities, and force responses at selectively identified subsets of interesting points can evaluate noise characteristics. An “as designed” model may evaluate noise source characteristics at the beginning of the life of an assembly. Degraded models can determine the effects of aging and use. A restored model may evaluate the influence of optimal fastener design on BSR characteristics for assembly resulting from fastener degradation.

Abstract: An active noise control system is capable of canceling out noise in the passenger compartment of a vehicle based on low-frequency road noise. The active noise control system has a feed-forward control unit for being supplied with reference signals highly correlated to noise from a noise source and generating a noise cancellation signal which is out of phase to noise in the passenger compartment of the vehicle, and a canceling sound generating unit disposed in the passenger compartment for generating a noise canceling sound in response to the noise cancellation signal from said feed-forward control unit. The active noise control system also has microphones for generating reference signals which are positioned respectively near the base of the front seat, near the center of a roof, and within a trunk compartment, i.e., respectively at vibrational antinodes of a primary or secondary acoustic normal mode of the passenger compartment in the longitudinal direction thereof.

Abstract: While a vehicle incorporating an active vibration noise control apparatus is decelerating, hysteresis is given if an operating point moves from an operating point on a sampling period characteristic curve to an operating point on another sampling period characteristic curve. Even if a base period detected depending on noise contains fluctuations, a smooth noise control process is performed. Since a division number produced when the base period is divided by a sampling period is a real number, the freedom of design is widened. Less strict limits are posed on the processing capability of a CPU of the active vibration noise control apparatus to provide a wider control range.

Abstract: An engine is supported on a vehicle body frame through an active vibration-isolating device. The vibration of the engine is prevented from being transmitted to the vehicle body frame by controlling the active vibration-isolating device. A speaker is disposed within a vehicle compartment. The noise is reduced by adaptively controlling the speaker based on a rotational speed of the engine and a noise detected by a microphone disposed within the vehicle compartment. Thus, the vibration and noise characteristics of the vehicle can be improved by a synergic effect of reducing both the vibration and the noise. Further, because the microphone is inexpensive and the speaker for an audio set can be used without any modification, the present invention can be achieved with a low cost.

Abstract: An apparatus and method for noise reduction employ a first processor having one or more channels, each channel comprising a respective first processor filter, and each channel configured to receive a respective one of one or more input signals. The first processor is configured to provide an intermediate output signal. The apparatus and method further employ a second processor including a second processor filter configured to receive the intermediate output signal and to provide a noise-reduced output signal. The apparatus and method further employ a first adaptation processor coupled to the first processor and a second adaptation processor coupled to the second processor. In some embodiments, an echo canceling processor reduces an echo portion associated with the noise-reduced output signal. In some embodiments, a response of the first filter portion and of the second filter portion are dynamically adapted.

Abstract: An active noise control system (100) and method compensates for changes in a microphone output to maintain accurate noise control. A calibration signal reflecting a desired microphone output is generated and stored in an active noise control module (106). During operation, the active noise control module (106) compares an actual microphone output signal with the calibration signal and compensates for any changes in the actual output signal before any noise compensation or cancellation function occurs.

Abstract: An active noise control system (100) and method modifies a noise made when a vehicle closure, such as a door, hood, or trunk, closes by detecting the closure's velocity and selecting a delay time and control noise amplitude appropriate for the velocity. By modifying the noise of a vehicle door closing, the system (100) can reduce the frequency and reverberation of the noise generated by the door, improving user perception of the vehicle itself.

Abstract: An active noise cancellation system (26) for controlling engine noise propagation through a vehicle induction system (32) is customizable to achieve a desired engine noise profile. A controller (34) of the active noise cancellation system drives a speaker (36) to generate a noise cancellation sound in a manner consistent with an individual's indicated preference for a specific type of available engine noise profile. By customizing how the speaker is driven, the system customizes the resulting engine noise heard in the passenger compartment. In one example, the system is customizable using a hand held communication device (24) such as a cell phone, a personal digital assistant or a so-called palm top computer. In another example, a resident communication bus on the vehicle is accessed through a user communication interface (28) supported on the vehicle.

Abstract: The method of noise attenuation comprises the steps of generating a noise canceling signal, sensing for an system condition, and ceasing the generation of the noise canceling based upon the system condition. This method is embodied in a system that includes an air induction body, a speaker in proximity to the air induction body, a sensor for sensing a system condition, and a control unit with a noise cancellation feature. The control unit is in communication with both the speaker and the sensor. Based upon the sensed system condition, the control unit may disable the noise cancellation feature.

Abstract: A system for microphone noise reduction includes first and second filter portions and a control processor adapted to adapt the first and second filter portions in response to a one of a plurality of stored vectors. Each stored vector is representative of acoustic transfer functions in accordance with a model of a vehicle and a respective position within the vehicle. A method for processing microphone signals includes selecting a vehicle model, selecting positions within the vehicle model, measuring acoustic response vectors at the positions, storing the response vectors, selecting one of the response vectors, and adapting first and second filter portions in accordance with the selected response vector.

Abstract: In a microphone mounting for a hands-free system in automotive vehicles, the microphone is mounted on the seat belt. In one embodiment the microphone is seated in a sheath which is fastened to the upper belt deflection and through which the belt can freely pass. The sheath consists of two mutually displaceable flat sleeves, of which the lower one accommodates the microphone whose position relative to the passenger's mouth can be adjusted in an optimum way by a mutual displacement of the two sleeves. In another embodiment the microphone is provided at its side facing the belt with contacts that are brought into electrical contact with conducting wires integrated into the belt so as to be connected to the telephone circuit.

Abstract: An apparatus for producing sounds corresponding to the operation of an internal combustion engine in the interior space of a motor vehicle is characterized by a pressure sensor (20) that detects fluctuations in pressure in a fresh air stream into the engine, an amplification device (32, 33) for amplifying output signals of the pressure sensor, and at least one speaker (34) attached to the amplifier and arranged in the interior space of the vehicle for reproducing the amplified signals.

Abstract: An active noise control system is capable of canceling out noise in the passenger compartment of a vehicle based on low-frequency road noise. The active noise control system has a feed-forward control unit for being supplied with reference signals highly correlated to noise from a noise source and generating a noise cancellation signal which is out of phase to noise in the passenger compartment of the vehicle, and a canceling sound generating unit disposed in the passenger compartment for generating a noise canceling sound in response to the noise cancellation signal from said feed-forward control unit. The active noise control system also has microphones for generating reference signals which are positioned respectively near the base of the front seat, near the center of a roof, and within a trunk compartment, i.e., respectively at vibrational antinodes of a primary or secondary acoustic normal mode of the passenger compartment in the longitudinal direction thereof.

Abstract: An active noise attenuation system for an air induction assembly includes a housing that is mounted to a vehicle structure and a speaker assembly that is mounted within the housing to generate a sound field for attenuating noise. The housing defines an air inlet duct open end through which air is drawn. A microphone detects noise and modifies an anti-noise signal that is sent from an electronics center. The electronics center receives the signal, mixes with other engine signals, phase-shifts the signal, and sends the phase-shifted signal to the speaker to attenuate the noise. The speaker includes electrical connections that extend outwardly toward the air inlet duct open end for connection to the electronics center. The microphone and speaker are connected to the electronics center with flex cables.

Abstract: An active noise control system includes a source unit for generating regenerative signals, an ANC unit for processing signals so as to actively cancel noise, sensors for detecting the information on the inside and outside of a vehicle, a vehicle interior voice discriminating unit for discriminating voice of conversation generated in the vehicle interior, an amplifier for amplifying the signals processed by ANC unit and reproducing transducers for reproducing the signals amplified by the amplifier.

Abstract: An air induction system comprises an air induction body and air filter to provide filtered air to a vehicle engine. A microphone is disposed within the air filter. A control unit may receive signals from the microphone. The control unit may further control a speaker, which produces a noise canceling sound to thereby reduce engine noise associated with the air induction system.

Abstract: Transitory audio information that is subject to interruption is provided without loss of content. Transitory audio information received from an audio source is audibly provided until an interrupt signal is received. The transitory audio information is buffered while a message associated with the interrupt signal is audibly provided. Upon conclusion of the message, the buffered transitory audio information is audibly provided.

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 integrating apparatus to lower the levels of audio outputs of an on-board audio system immediately upon cessation of a noise level such as when a vehicle comes to a stop. Audio signals from an audio source are amplified through attenuating means by an amplifying means to drive a loudspeaker. An output of a microphone for detecting a noise is inputted to each of two integrating circuits, which have different fall time constants. Outputs of the integrating circuits are applied to a selectively outputting means, which selectively derives an output having a lower level among the outputs of the integrating circuits, and which then supplies the output as a control signal to the attenuating means. When the level of noise is high such as when the vehicle is running, the control signal has a high level and the attenuating means reduces an attenuation. Thus, the output of the audio source may be heard without a drift of the audio signal level.

Abstract: An active noise control system for reducing road noise of low frequency generated inside the cabin of a vehicle is provided. The active noise control system includes a noise detector, a signal generator for processing the input noise signal to generate a signal for producing noise canceling waves, a limiting amplifier having a specified threshold value for variably amplifying the processed signal so that the amplitude of output signal will not exceed the threshold value, and an electrical acoustic converter for producing noise canceling acoustic waves in accordance with the output signal.

Abstract: A noise attenuation system (10) for an air induction system (12) includes an air inlet duct (16) having an open end (18) to draw in air and a loudspeaker (22) mounted within the inlet duct (16) and facing the open end (18) of the inlet duct (16). The air horn (24) is connected to the loudspeaker (22) to tune the sound output and increase the sound power from the loudspeaker (22) to optimize cancellation of noise generated by the air induction system (16) at lower frequencies. An open end (18) of the air horn (24) is positioned within a plane defined by the open end (18) of the air inlet duct (16). A microphone (26) is positioned near the air inlet duct (16) and is in communication with a controller (28). The controller (28) generates an input to the loudspeaker (22). The input to the loudspeaker (22) is out of phase with the noise detected by the microphones (26) to cancel a portion of noise emitted from the open end (18) of the air inlet (16).

Abstract: An active noise attenuation system for an air induction assembly is operably connected to an engine that generates a low frequency noise having a noise profile defining a peak noise. The system has an air inlet duct housing with an inlet and an outlet connected to the engine. A resonator is supported by the housing and is positioned between a speaker assembly and the engine to attenuate the peak noise resulting in an attenuated low frequency engine noise. A microphone senses the attenuated low frequency engine noise and generates an attenuated low frequency engine noise signal. A controller receives and phase shifts the signal and sends the signal to the speaker to generate a sound field to cancel or reduce the attenuated low frequency engine noise signal.

Abstract: An active noise control system (20) includes a controller (34) that receives a signal from a single pressure sensor (36). The controller (34) estimates an engine speed of an engine (30) and a throttle position of a throttle valve associated with an air intake manifold (32). The controller (34) generates a noise control signal that drives a speaker (38), which responsively generates a noise attenuation signal. The disclosed embodiment may be used in an after-market product as it requires minimal interfacing with other vehicle electronics.

Abstract: An active noise cancellation system has a speaker which is utilized to generate sound to cancel engine noise, as is known. An operator horn switch communicates with a control for the active noise cancellation system. Upon receiving a request from the operator for a horn signal, the control for the active noise cancellation system generates a horn tone from the speaker associated with the active noise cancellation system. If cancellation is in progress, the cancellation is preferably paused during the period of time when the horn signal is being emitted.

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 apparatus and method for determining when a component of a work vehicle experiences vibration above a predetermined threshold, and responding to the vibration so that the vibration is reduced below the predetermined threshold. The apparatus, which is in a work vehicle that includes a chassis, an operator's cab and an active cab suspension system, includes a sensor that is configured to sense a quantity representative of the vibration experienced by the component of the work vehicle and to develop a first signal indicative of that quantity. The apparatus also includes a signal processor that is coupled to the sensor and is configured to develop, in response to the first signal, a second signal indicative of whether the vibration experienced by the component is above the predetermined threshold.

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: In an active noise control apparatus in which an audio signal and a noise control signal are mixed to thereby sound a loudspeaker inside a motor vehicle, a general-purpose audio head unit cannot conventionally be freely changed for the one already mounted on the motor vehicle. As a solution, an active noise control unit is provided with a buffer amplifier and a mixer. An audio signal amplified by a power amplifier in an audio head unit is adjusted in level by the buffer amplifier such that a level of an audio signal outputted after amplification by the first amplifier becomes substantially equal to a level of the audio signal outputted from the audio head unit. Then, at the mixer, a noise control signal outputted from an active noise controller is added to an audio signal outputted from the buffer amplifier. Therefore, any audio head unit can be freely changed for the one already mounted on the vehicle as long as the audio head unit contains therein a power amplifier.

Abstract: The invention refers to a device for sound control in a space (2) with a sound field from at least one sound source (3). The device includes a pulse sensor (5), which provides a pulse signal from the sound source (3). Moreover, the device includes a number of sound influencing members (8) for reducing the sound field in the space (2) and a number of sound sensors (9), which sense the actual sound field in the space and provide an error signal. A control unit includes a signal supplied device (11, 12), which receives a pulse signal and supplies a first signal to an adaptive filter (15). The filter has a number of filter coefficients and generates a drive signal for each sound influencing member (8). The signals supply device also supplies second signals to a calculating member (24), which calculates the value of the filter coefficients by the second signals and the error signals for updating the adaptive filter (15).

Abstract: A method of forecasting the comfort performance in a vehicle equipped with a test mounted assembly in a selected position, traveling at speed V over smooth ground, with a maximum speed Vmax, by establishing a vehicle transfer function where the assembly has a tire with N substantially identical irregularities on its circumference, regularly distributed to excite the vehicle in a range of frequencies, measuring the forces at the wheel center, and multiplying the forces by the vehicle transfer function to forecast the noise and vibrations.

Abstract: An active vibratory noise control apparatus has a speaker for canceling vibratory noise in the passenger compartment of a vehicle, the speaker being used as a speaker of one of different audio devices that can be installed on the vehicle. Each of the audio devices has a command key switch assembly. When the command key switch assembly is operated to turn off the transistor, a control signal is applied to a switching control circuit in an active vibratory noise control unit, which identifies the audio device installed on the vehicle. The active vibratory noise control unit generates a canceling signal matching characteristics of the speaker of the identified audio device for canceling vibratory noise in the passenger compartment.

Abstract: An active vibratory noise control apparatus reduces vibratory noise which is produced in the passenger compartment of a vehicle based on vibratory noise generated by a variable-cylinder internal combustion engine that can selectively be operated in a full-cylinder operation mode in which all of the cylinders are operated and a partial-cylinder operation mode in which some of the cylinders are out of operation. The active vibratory noise control apparatus has a partial-cylinder operation mode determining circuit for determining whether the variable-cylinder internal combustion engine is in the partial-cylinder operation mode or not. Depending on a determined result from the partial-cylinder operation mode determining circuit, a transistor is turned on or off to switch an amplifying circuit which drives a speaker into and out of operation.