EP0858651B1 - Dispositif d'attenuation acoustique active destine a etre dispose a l'interieur d'un conduit, en particulier pour l'insonorisation de reseau de ventilation et/ou de climatisation - Google Patents

Dispositif d'attenuation acoustique active destine a etre dispose a l'interieur d'un conduit, en particulier pour l'insonorisation de reseau de ventilation et/ou de climatisation Download PDF

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Publication number
EP0858651B1
EP0858651B1 EP96937355A EP96937355A EP0858651B1 EP 0858651 B1 EP0858651 B1 EP 0858651B1 EP 96937355 A EP96937355 A EP 96937355A EP 96937355 A EP96937355 A EP 96937355A EP 0858651 B1 EP0858651 B1 EP 0858651B1
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EP
European Patent Office
Prior art keywords
duct
attenuation
signal
sound
sensor
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Expired - Lifetime
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EP96937355A
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German (de)
English (en)
French (fr)
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EP0858651A1 (fr
Inventor
Christian Carme
Virginie Delemotte
Pierre Chaffois
Patrick Damizet
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Aldes Aeraulique SA
Technofirst SA
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Aldes Aeraulique SA
Technofirst SA
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    • G—PHYSICS
    • G10—MUSICAL INSTRUMENTS; ACOUSTICS
    • G10K—SOUND-PRODUCING DEVICES; METHODS OR DEVICES FOR PROTECTING AGAINST, OR FOR DAMPING, NOISE OR OTHER ACOUSTIC WAVES IN GENERAL; ACOUSTICS NOT OTHERWISE PROVIDED FOR
    • G10K11/00—Methods or devices for transmitting, conducting or directing sound in general; Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
    • G10K11/16—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
    • G10K11/175—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general using interference effects; Masking sound
    • G10K11/178—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general using interference effects; Masking sound by electro-acoustically regenerating the original acoustic waves in anti-phase
    • G10K11/1785—Methods, e.g. algorithms; Devices
    • G10K11/17857—Geometric disposition, e.g. placement of microphones
    • G—PHYSICS
    • G10—MUSICAL INSTRUMENTS; ACOUSTICS
    • G10K—SOUND-PRODUCING DEVICES; METHODS OR DEVICES FOR PROTECTING AGAINST, OR FOR DAMPING, NOISE OR OTHER ACOUSTIC WAVES IN GENERAL; ACOUSTICS NOT OTHERWISE PROVIDED FOR
    • G10K11/00—Methods or devices for transmitting, conducting or directing sound in general; Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
    • G10K11/16—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
    • G10K11/175—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general using interference effects; Masking sound
    • G10K11/178—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general using interference effects; Masking sound by electro-acoustically regenerating the original acoustic waves in anti-phase
    • G10K11/1785—Methods, e.g. algorithms; Devices
    • G10K11/17861—Methods, e.g. algorithms; Devices using additional means for damping sound, e.g. using sound absorbing panels
    • G—PHYSICS
    • G10—MUSICAL INSTRUMENTS; ACOUSTICS
    • G10K—SOUND-PRODUCING DEVICES; METHODS OR DEVICES FOR PROTECTING AGAINST, OR FOR DAMPING, NOISE OR OTHER ACOUSTIC WAVES IN GENERAL; ACOUSTICS NOT OTHERWISE PROVIDED FOR
    • G10K11/00—Methods or devices for transmitting, conducting or directing sound in general; Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
    • G10K11/16—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
    • G10K11/175—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general using interference effects; Masking sound
    • G10K11/178—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general using interference effects; Masking sound by electro-acoustically regenerating the original acoustic waves in anti-phase
    • G10K11/1787—General system configurations
    • G10K11/17879—General system configurations using both a reference signal and an error signal
    • G10K11/17881—General system configurations using both a reference signal and an error signal the reference signal being an acoustic signal, e.g. recorded with a microphone
    • G—PHYSICS
    • G10—MUSICAL INSTRUMENTS; ACOUSTICS
    • G10K—SOUND-PRODUCING DEVICES; METHODS OR DEVICES FOR PROTECTING AGAINST, OR FOR DAMPING, NOISE OR OTHER ACOUSTIC WAVES IN GENERAL; ACOUSTICS NOT OTHERWISE PROVIDED FOR
    • G10K2210/00—Details of active noise control [ANC] covered by G10K11/178 but not provided for in any of its subgroups
    • G10K2210/10—Applications
    • G10K2210/104—Aircos
    • G—PHYSICS
    • G10—MUSICAL INSTRUMENTS; ACOUSTICS
    • G10K—SOUND-PRODUCING DEVICES; METHODS OR DEVICES FOR PROTECTING AGAINST, OR FOR DAMPING, NOISE OR OTHER ACOUSTIC WAVES IN GENERAL; ACOUSTICS NOT OTHERWISE PROVIDED FOR
    • G10K2210/00—Details of active noise control [ANC] covered by G10K11/178 but not provided for in any of its subgroups
    • G10K2210/10—Applications
    • G10K2210/112—Ducts
    • G—PHYSICS
    • G10—MUSICAL INSTRUMENTS; ACOUSTICS
    • G10K—SOUND-PRODUCING DEVICES; METHODS OR DEVICES FOR PROTECTING AGAINST, OR FOR DAMPING, NOISE OR OTHER ACOUSTIC WAVES IN GENERAL; ACOUSTICS NOT OTHERWISE PROVIDED FOR
    • G10K2210/00—Details of active noise control [ANC] covered by G10K11/178 but not provided for in any of its subgroups
    • G10K2210/30—Means
    • G10K2210/301—Computational
    • G10K2210/3027—Feedforward
    • G—PHYSICS
    • G10—MUSICAL INSTRUMENTS; ACOUSTICS
    • G10K—SOUND-PRODUCING DEVICES; METHODS OR DEVICES FOR PROTECTING AGAINST, OR FOR DAMPING, NOISE OR OTHER ACOUSTIC WAVES IN GENERAL; ACOUSTICS NOT OTHERWISE PROVIDED FOR
    • G10K2210/00—Details of active noise control [ANC] covered by G10K11/178 but not provided for in any of its subgroups
    • G10K2210/30—Means
    • G10K2210/321—Physical
    • G10K2210/3214—Architectures, e.g. special constructional features or arrangements of features
    • G—PHYSICS
    • G10—MUSICAL INSTRUMENTS; ACOUSTICS
    • G10K—SOUND-PRODUCING DEVICES; METHODS OR DEVICES FOR PROTECTING AGAINST, OR FOR DAMPING, NOISE OR OTHER ACOUSTIC WAVES IN GENERAL; ACOUSTICS NOT OTHERWISE PROVIDED FOR
    • G10K2210/00—Details of active noise control [ANC] covered by G10K11/178 but not provided for in any of its subgroups
    • G10K2210/30—Means
    • G10K2210/321—Physical
    • G10K2210/3219—Geometry of the configuration
    • G—PHYSICS
    • G10—MUSICAL INSTRUMENTS; ACOUSTICS
    • G10K—SOUND-PRODUCING DEVICES; METHODS OR DEVICES FOR PROTECTING AGAINST, OR FOR DAMPING, NOISE OR OTHER ACOUSTIC WAVES IN GENERAL; ACOUSTICS NOT OTHERWISE PROVIDED FOR
    • G10K2210/00—Details of active noise control [ANC] covered by G10K11/178 but not provided for in any of its subgroups
    • G10K2210/50—Miscellaneous
    • G10K2210/509—Hybrid, i.e. combining different technologies, e.g. passive and active

Definitions

  • the present invention relates to acoustic attenuation activates an acoustic signal propagating in a space confined, such as a conduit.
  • Active acoustic attenuation is the operation which consists in attenuating an acoustic signal, by electronically creating another acoustic signal similarly amplitude that the acoustic signal to attenuate, and in opposition phase with respect to it.
  • An acoustic signal to be attenuated here means noise from any source of noise and likely to spread in the conduit.
  • electronic control means include filtering means whose coefficients are adapted, in real time, according to an algorithm chosen for minimize the energy of the acoustic error signal as a function of the reference acoustic signal.
  • This installation has the advantage of generating only a small pressure loss due solely to the presence of microphones error and reference inside the duct.
  • the location of the attenuation source in the wall of the duct sheath most often generates parasitic phenomena, which can disturb the attenuation active. These phenomena, called “rejection phenomena”, most often occur at relatively frequent frequencies bass, typically from the first angular wave mode sound.
  • a known solution is to choose for electronic control means (in particular conditioning or anti-recovery filters and smoothing) a cutoff frequency lower than the frequency of appearance of the first mode sound waves angular.
  • a solution known to favor a time delay acoustic (propagation of sound waves) greater than electrical time delay (from signal propagation electronic), consists of placing the reference microphone at a relatively large distance from the source mitigation. In practice, this distance is chosen equal at least four times the diameter of a circular duct.
  • This type of installation does not provide for the use of a microphone of reference to participate in the development of the signal acoustic attenuation. It is a simple filtering by feedback.
  • the axis of symmetry of the radiation of the attenuation source is here perpendicular to the direction propagation of sound waves, which limits the efficiency active acoustic attenuation because this arrangement asymmetrical generates parasitic sound waves (equivalent to those of the first angular mode or "mode transverse "), from the frequency of appearance of such fashion. If necessary, this provision is effective for the treatment of the only transverse mode.
  • document FR-A-2275722 describes a device comprising a reference microphone and a noise reduction source arranged inside a pipeline. There is no error microphone placed near the source of the counter-noise.
  • the device is therefore not adaptive. It only allows fail to obtain satisfactory mitigations when physical parameters of the pipeline (temperature, fouling, ...) evolve.
  • the present invention aims to improve installations active acoustic attenuation.
  • the first sensor means and actuator means are separated from each other from a small distance, significantly less to the diameter or the smallest dimension of the section of the duct and arranged entirely inside the duct, at a chosen distance from the duct sheath, and the axis of symmetry of the radiation of the actuator means and the axis of symmetry of the first sensor means are substantially parallel to the direction of propagation of the acoustic signal in the conduit.
  • the first sensor means and the actuator means are arranged substantially in the axis central duct.
  • the device comprises a fixed frame (or bulb) capable of supporting actuator means and the first sensor means according to a chosen arrangement to avoid the creation of waves noise and whose dimensions and shape are chosen to limit the pressure drop in the duct.
  • the framework supports attenuation means passive acoustics arranged in an arrangement chosen for facilitate the directivity of the radiation of the actuating means, and whose volume is optimized thanks to the attenuation active to limit pressure drop and reduce bulk of the device in the conduit.
  • fixing means to fix the framework inside the duct are provided for a selected distance from the sheath of said conduit, and the dimensions and shape are chosen to limit the loss of load in the conduit.
  • the framework is monobloc, with low loss charging, and compact.
  • second sensor means arranged at a second place inside the duct, upstream from the first place according to the direction of propagation of the acoustic signal in the duct and suitable for picking up a second acoustic signal at least at one point of said second location, and in which the electronic control means generate the signal active acoustic attenuation for the actuator means, in order to minimize the energy of the first acoustic signal, by function of the first and second acoustic signals as well captured.
  • Such a device constitutes an active acoustic attenuator of the type with anticipation filtering (also called FEED FORWARD CONTROL).
  • the framework supports the second sensor means inside the duct at a selected distance from the sheath of the conduit as well as actuator means.
  • the fixing means at the point of contact with the duct sheath, are covered with a material vibration damper.
  • the electronic means control means include filtering means the coefficients are adapted in real time according to an algorithm chosen to minimize the energy of the first acoustic signal based on the second acoustic signal.
  • the conduit is subdivided into a plurality of sub-conduits with or without sheath (with or without partitioning), each sub-duct being associated with a framework disposed inside said sub-duct, the plurality of frameworks forming a single structure with or without means passive attenuation.
  • a device constitutes a system multi-way.
  • the plurality of frameworks is arranged substantially in the central axis of the duct.
  • one at less of the frames, among said plurality, is disposed substantially in the central axis of the conduit.
  • the means control electronics are common to the plurality of frameworks.
  • the electronic control means are subdivided into independent and associated electronic control means each with actuator and sensor means of each frame.
  • the second sensor means are common to the plurality of frameworks.
  • the duct sheath located at a selected distance from the source and at least first sensor means comprises passive acoustic attenuation means for the sheath.
  • the device according to the invention also applies to ducts of oblong, square, rectangular section, or other.
  • the fluid can be not only air but also another gas, or water. There may or may not be flow of fluid.
  • the device according to the invention can be installed at any opening between a noisy place and a place to be soundproofed.
  • the device according to the invention is applied to a ventilation unit, for example the VEC271B unit sold by the company ALDES.
  • a ventilation unit for example the VEC271B unit sold by the company ALDES.
  • Electronic control means that deliver the signal active acoustic attenuation at the source of the counter-noise preferably use the filtering technique by anticipation also called FEED FORWARD CONTROL.
  • the essential characteristics of the device namely especially its particular arrangement inside the conduit can also be applied to filtering means by feedback also called FEED-BACK CONTROL.
  • the device comprises a sensor 2 placed at a location 3 inside the core 4 of a circular duct 1.
  • This sensor receives a first signal acoustic e (called error) at least at point 3 of the drove.
  • a source of attenuation 6 is disposed inside of the soul 4 of the conduit. This source delivers an attenuation signal acoustic active in response to a control signal chosen which will be described in more detail below.
  • Electronic control means (not shown in Figures 1 and 2) generate the acoustic attenuation signal active for the source, depending on at least the first signal acoustic e.
  • first means sensors 2 and source 6 are arranged entirely inside of the duct, facing each other, and to a chosen distance from the duct sheath.
  • the axis of symmetry of the radiation of the source and the axis of symmetry of the first means sensors are substantially parallel to the direction of propagation of the acoustic signal in the duct.
  • the source is a speaker diaphragm M and coil B.
  • the axis of radiation of the loudspeaker ARS is here the main axis of the loudspeaker on which the physical quantities (intensity, efficiency, pressure) are maximum.
  • the first sensors 2 include at least one microphone S, unidirectional, formed of a sensitive capsule C, itself wrapped in a protective E envelope.
  • the AS axis of symmetry of the microphone is represented.
  • the microphone is connected to electronic means control via conventional L cables.
  • the iso-sensitivity curves are also shown in figure 5.
  • the senor 2 and the source 6 are arranged here substantially in the central axis 10 of the conduit.
  • the fact of arranging the source and the sensor inside the duct, and according to the layout described above confers many advantages.
  • the sound vibrations caused by the source according to the invention are taken into account in full by the electronic control means.
  • sensor (microphone) and actuator (speaker) means of the device according to the invention are supported at the interior of the duct by a framework (or bulb) whose shape and dimensions are chosen especially in view avoid the appearance of spurious sound waves and limit the pressure drop in the duct.
  • this framework is fixed inside the duct by fixing means which are covered, for the parts in contact with the duct sheath, of a material having vibration damping properties.
  • these means vibration dampers are easy to set up square.
  • the source 6 is housed at the end 11 of an acoustic enclosure 12.
  • the enclosure is cylindrical in shape.
  • Source 6 is arranged at one 11 of the ends of the cylinder so that the radiating surface of the source is opposite the microphone error 2.
  • the enclosure is made of a rigid material, for example PVC, or sheet metal.
  • the length of the speaker is from 800 to 1000 mm. Its diameter is around 100 at 300 mm.
  • the distance between the radiating surface of the speaker 6 and microphone 2 is of the order of 150 to 300 mm.
  • the internal wall 14 of the acoustic enclosure 12 is advantageously covered with passive absorption material.
  • this passive sound absorption material is rock wool.
  • the thickness of the wool rock is here of the order of 10 to 30 mm.
  • the acoustic enclosure 12 is itself supported by a framework 16 of cylindrical shape such as a shell or a bulb.
  • the outer wall 15 of the frame 16 is constituted of a rigid perforated material favoring passive absorption and avoiding the erosion of rock wool by the air flow.
  • the rigid material of the shell is a sheet perforated metal.
  • the perforation rate is at least around 30% in area. Perforation promotes energy absorption acoustics by bringing rock wool into contact with the medium in which the sound waves propagate.
  • the space between the external wall 15 of the frame and the outer wall 13 of the enclosure 12 is filled of rock wool.
  • the inner wall 19 of the sheath 18 of the duct is also provided with means for passive acoustic attenuation.
  • the inner wall 19 of the sheath 18 is made of a material such as a perforated sheet.
  • a passive acoustic attenuation material is advantageously housed between the inner wall 19 and the outer wall 20 of the sheath 18 of the duct.
  • this passive acoustic attenuation material is also rock wool.
  • the thickness of the rock wool is of the order of 25 to 50 mm and its density is of the order of 40 kg / m 3 to 70 kg / m 3 .
  • the part of the duct sheath equipped with passive acoustic attenuation means opposite of the bulb improves the overall attenuation of the device according to the invention in a wide frequency band.
  • This part of the sheath is most often intended to be assembled to another sheath devoid of passive attenuation.
  • the senor 2 is a flooded microphone in a hemisphere 40 made of a material having advantageously transparent acoustic properties.
  • This material is for example open cell foam. This material avoids air turbulence noise, which promotes good signal capture acoustic.
  • the hemisphere 40 is supported by a ring 42 disposed at a chosen distance from the source 6 thanks to two feet 44 whose length determines the distance between the surface radiating from the source and the equatorial section 41 of the half-sphere 40.
  • the space between the radiating surface of the source and the section 41 can be empty or fully filled or partially delimited open cell foam, or other material acoustically transparent.
  • the space between the source 6 and the sensor 2 is delimited by a thin or thin fabric open cell foam layer.
  • These materials are advantageously acoustically transparent.
  • the property "acoustically transparent” here gives the advantage of improving turbulence filtering for the error microphone 2. Likewise, it improves the filtering of dust. He avoids also the detachments of the air flow.
  • the electronic means of control are advantageously but not limited to type with anticipatory filtering means.
  • a reference sensor 50 disposed in a second place 51 of the conduit, upstream of the first location 3 depending on the direction of propagation of the acoustic signal in the conduit.
  • This sensor 50 is capable of picking up a second acoustic signal at least at a point 51 of the duct.
  • This second acoustic signal constitutes the reference signal r that will use the electronic control means.
  • this sensor 50 is placed close to from the end 9 of the enclosure 12 which is longitudinally opposite the end 11 of the acoustic enclosure 12 in which source is inserted.
  • the sensor 50 is also embedded in a hemisphere 53 in open cell foam.
  • the hemisphere 53 is attached to the end 9 of the acoustic enclosure 12.
  • the frame 16 and the sensors 2 and 50 are kept at the interior of the duct by fixing means which consist of fins 32, 34 and 36 extending along the framework, at the equatorial section 41 of the half-sphere 40 to the level of the end 9 of the enclosure 12. These fixing means make it possible to fix the framework to a chosen distance from the duct sheath.
  • these fins can be individual or formed a sort of three-branch spider, this which allows to form a common fixation for the source and the sensors.
  • This common fixing allows a set up easy of the acoustic attenuation device according to the invention.
  • it is compact, and has a aerodynamic shape which does not increase the pressure drop in the conduit.
  • the ends of the fins at the place of contact with the duct sheath are covered with a vibration damping material, for example a material elastomer type.
  • the ratio between the outside diameter of the framework and the internal diameter of the duct must remain significantly less than 0.6.
  • the implantation of the framework in the center of the duct shortens the distance between the microphone 2 and the attenuation speaker 6.
  • the speaker should be kept at a distance of about 15 to 30 cm from the error microphone.
  • the distance theoretical minimum between speaker 6 and microphone 50 corresponds to two diameters of the conduit. This minimum theoretical distance is to be compared with a length theoretical equivalent to four diameters in the case of a source arranged in the wall of the duct sheath, as in Patent FR-83 13502 mentioned above.
  • the radiating surface of the speaker may be perpendicular to the direction of wave propagation sound, but also parallel or at a certain angle. However, it is when the radiating surface of the speaker is substantially perpendicular to the direction of sound wave propagation that the speaker is actually directive.
  • the complementarity of the mitigation elements passive improves directivity all the more because the waves sound propagating from the attenuation source upstream for example are amortized by the passive device. Moreover, it is when the radiating surface of the attenuation source is substantially perpendicular to the direction of sound wave propagation that the attenuation device active acoustics according to the invention is symmetrical by relative to the axis of symmetry of the duct.
  • the angular modes being asymmetrical, they risk to be slightly excited by a speaker placed so asymmetrical.
  • the speaker is the one sold by the company AUDAX under the reference HT 130k0.
  • control and reference microphones are for example unidirectional microphones sold under the reference EM357 by POOKOO INDUSTRIAL.
  • FIGS. 6 and 7 illustrate schematically the architecture and the functional aspect electronic means for active attenuation control according to the invention in the case of a single-channel system.
  • control means who are going to be able to generate the attenuation signal active acoustics at source 6 are articulated here around means of advance filtering. These control means are advantageously housed inside the frame. They can also be accommodated in the duct sheath.
  • These anticipation filtering means include a first acquisition block 100 having an input 102 connected to sensor 50 and an output 104. Likewise, provision is made for sensors 2 an acquisition block 110 having a input 112 connected to the sensor means 2, and an output 114.
  • acquisition blocks 100 and 110 carry their signals respective to a processor 130 having an input 132 connected to input 104 and an input 134 connected to output 114.
  • the processor 130 is advantageously a type processor DSP for DIGITAL SIGNAL PROCESSOR.
  • the processor 130 is that sold by TEXAS INSTRUMENTS under the reference TMS 320C25.
  • the processor 130 has an output 136 delivering a signal digital to a 140 rendering block.
  • This 140 block has an input 142 connected to output 136 and an output 144 linked to source 6.
  • the acquisition blocks 100 and 110 are acquisition blocks an analog signal to convert it to digital for processor 130.
  • each acquisition block 100 and 110 includes a preamplifier, followed in series by a conditioning filter, for example an anti-recovery filter and finally followed by an analog / digital converter.
  • a conditioning filter for example an anti-recovery filter
  • the restitution block 140 is a device whose function is to ensure the conversion of a signal digital to analog.
  • such a restitution block includes a digital / analog converter followed by a filter smoothing, for example a low-pass filter, and an amplifier audio.
  • the processor 130 is capable of driving an algorithm of minimization so that the signal e picked up by the sensor 2 has the lowest possible energy. This action is carried out through the delivery of a signal u which excites the attenuation source 6 so that the wave of counter-noise emitted by source 6 has the same amplitude than the signal picked up by the sensor 50, but in opposition to phase with respect to it to attenuate the noise that propagates in the duct from location 51 to location 3.
  • the minimization algorithm is an algorithm LMS type for LEAST MEANS SQUARE or LESS SQUARE WAY.
  • sampling frequency of analog / digital converters is chosen carefully to avoid introduce an annoying time delay at the level of the propagation of electronic signals.
  • the processor acquires periodically, and in in real time, the reference noise r picked up by the sensor 50. These processing means also calculate the energy of the signal e picked up by the error sensor 2. Next, the means filtering are placed in search of optimal parameters W for the best active attenuation in order to determine, in real time, the values of the signal active acoustic attenuation control u.
  • the impulse responses brought into play are the impulse response Ho relative to the transfer function between sensor 50 and source 6 and the impulse response H relative to the transfer function between source 6 and error sensor 2.
  • the transfer function H includes an input receiving the signal u and an output delivering the signal y which corresponds to the active acoustic attenuation signal picked up by the sensor 2.
  • the Ho transfer function includes an input receiving the signal r and an output delivering the corresponding signal to the sound radiation from the source to be attenuated, picked up by the reference sensor 50.
  • the Ho function is most often advantageously negligible.
  • the transfer function H is measured as follows.
  • a first initialization step we measure the transfer function of the so-called secondary path between the source 6 and the error microphone 2 by an initialization method, for example by exciting source 6 with DIRAC type signals, white noise, filtered reference or analogues.
  • the transfer function H is sampled and saved in the memory of the DSP processor.
  • the function of transfer is sampled at the frequency of 5400 Hz on a number of 70 points.
  • the digital filter coefficients W are adapted by real time according to the LMS algorithm to minimize the signal e depending on the signal r (or b).
  • the operation of the device according to the invention is independent of the setting of the installation, the flow, the velocity of the fluid in the conduit, or accessories ventilation network present upstream or downstream of the device according to the invention.
  • the iterative LMS type minimization algorithm allows here to find the active attenuation whatever the type of noise source, for example fans or compressors or others.
  • the setting implementation and adaptation of the installation is very simple and does not call on acoustic specialists or electronics engineers.
  • the device according to the invention is designed by incorporating attenuation, where appropriate passive, which provides very high performance interesting over the entire audible frequency band.
  • multi-channel system it may be necessary to insert several frameworks into the drove. There are then two categories of systems multi-channel: the coupled system and the decoupled system.
  • Each frame can be associated with a microphone respective reference 50 or a single reference microphone for the plurality of frames.
  • the COM electronic control means are common to the plurality of frames. They acquire nxm impulse responses Hij (i being an integer varying from 1 to n and j being an integer varying from 1 to m) on a selected number of points and at a frequency sampling method.
  • Electronic control means also acquire of n Hoi impulse responses to take into consideration of acoustic propagation between microphones error and reference microphones. Finally, in time real, they calculate the n Wi filters. Each of the filters and therefore each control signal depends on signals picked up by the reference microphone (s) and error microphones, and impulse responses.
  • the n error microphones and the m speakers are positioned in n ducts with sheathing ( Figures 12 and 13) or without sheath ( Figures 10 and 11).
  • the n conduits when are grouped together correspond to the total duct D.
  • the sheaths G1 to G3 of the sub-conduits SC1 to SC4 are here distinct from means of fixing the frames. Possibly, the means when full over the entire length of the device, can constitute the sheaths of the sub-conduits.
  • the electronic control means When decoupled, the electronic control means are subdivided into electronic control means COM1 and COM2 each associated with the actuator and sensor means each frame OS1 and OS2.
  • the second sensor means are common to the plurality of frameworks.
  • each frame thus constitutes a partitioning of the duct, changeable at will according to the application chosen.
  • the attenuation of the device according to the invention on the bass frequencies is in the case of a purely random noise of 10 dB at 125 Hz, 12 dB at 250 Hz, and 15 dB at 500 Hz.
  • the optimized combination of acoustic absorption active broadband and passive absorption allows obtain a satisfactory result for low frequencies, that is to say those below 1000 Hz in the case random noise.
  • the acoustic attenuation obtained is 13 dB at 125 Hz, 20 dB at 250 Hz, and 30 dB at 500 Hz.
  • the volume occupied by means of passive mitigation is relatively little bulky compared to the previous structures in order to limit the pressure drop and reduce the size of the device in the conduit. This reduced volume is optimized here thanks to the choice of active attenuation parameters according to the invention.

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  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Acoustics & Sound (AREA)
  • Multimedia (AREA)
  • Duct Arrangements (AREA)
  • Soundproofing, Sound Blocking, And Sound Damping (AREA)
  • Pipe Accessories (AREA)
  • Exhaust Silencers (AREA)
  • Sink And Installation For Waste Water (AREA)
EP96937355A 1995-10-30 1996-10-29 Dispositif d'attenuation acoustique active destine a etre dispose a l'interieur d'un conduit, en particulier pour l'insonorisation de reseau de ventilation et/ou de climatisation Expired - Lifetime EP0858651B1 (fr)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
FR9512802 1995-10-30
FR9512802A FR2740599B1 (fr) 1995-10-30 1995-10-30 Dispositif d'attenuation acoustique active destine a etre dispose a l'interieur d'un conduit, en particulier pour l'insonorisation de reseau de ventilation et/ou de climatisation
PCT/FR1996/001694 WO1997016816A1 (fr) 1995-10-30 1996-10-29 Dispositif d'attenuation acoustique active destine a etre dispose a l'interieur d'un conduit, en particulier pour l'insonorisation de reseau de ventilation et/ou de climatisation

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EP0858651A1 EP0858651A1 (fr) 1998-08-19
EP0858651B1 true EP0858651B1 (fr) 1999-06-16

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EP96937355A Expired - Lifetime EP0858651B1 (fr) 1995-10-30 1996-10-29 Dispositif d'attenuation acoustique active destine a etre dispose a l'interieur d'un conduit, en particulier pour l'insonorisation de reseau de ventilation et/ou de climatisation

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US (1) US7248704B2 (xx)
EP (1) EP0858651B1 (xx)
AT (1) ATE181444T1 (xx)
AU (1) AU719258B2 (xx)
CA (1) CA2233253C (xx)
DE (1) DE69602966T2 (xx)
ES (1) ES2134645T3 (xx)
FR (1) FR2740599B1 (xx)
HK (1) HK1015923A1 (xx)
WO (1) WO1997016816A1 (xx)

Families Citing this family (24)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
MY125833A (en) * 1997-06-06 2006-08-30 Carrier Corp Wall cavity microphone turbulence shield
US6084971A (en) * 1997-06-10 2000-07-04 Siemens Electric Limited Active noise attenuation system
DE19861018C2 (de) * 1998-12-15 2001-06-13 Fraunhofer Ges Forschung Gesteuerter akustischer Wellenleiter zur Schalldämpfung
DE60000904T2 (de) * 1999-09-14 2003-09-18 Siemens Vdo Automotive Inc., Chatham Aktiv gesteuerter Einlasslärm mit Multipole-Einlassvorrichtung
EP1085199B1 (en) * 1999-09-14 2003-03-12 Siemens VDO Automotive Inc. Actively controlled induction noise using a quadrapole inlet
GB0004243D0 (en) * 2000-02-24 2000-04-12 Wright Selwyn E Improvements in and relating to active noise reduction
FR2808916B1 (fr) * 2000-05-11 2003-08-15 Jean Laurent Peube Source et systeme electroaeroacoustiques pour controle actif du bruit
JP4409755B2 (ja) * 2000-12-15 2010-02-03 パナソニック株式会社 能動騒音制御装置
US7327849B2 (en) * 2004-08-09 2008-02-05 Brigham Young University Energy density control system using a two-dimensional energy density sensor
WO2007099541A2 (en) * 2006-03-02 2007-09-07 Silentium Ltd. Quiet active fan for servers chassis
US20110123036A1 (en) * 2006-03-02 2011-05-26 Yossi Barath Muffled rack and methods thereof
FR2905734B1 (fr) * 2006-09-07 2012-07-13 Airbus France Dispositif permettant d'ameliorer l'efficacite des traitements acoustiques dans un conduit d'une motorisation d'aeronef
US8855329B2 (en) * 2007-01-22 2014-10-07 Silentium Ltd. Quiet fan incorporating active noise control (ANC)
US7705522B2 (en) * 2008-06-06 2010-04-27 Toyota Motor Engineering & Manufacturing North America, Inc. Adjustable sound panel with electroactive actuators
JP5666797B2 (ja) * 2009-10-05 2015-02-12 フォスター電機株式会社 イヤホン
JP6182524B2 (ja) 2011-05-11 2017-08-16 シレンティウム リミテッド ノイズ・コントロールのデバイス、システム、および方法
US9928824B2 (en) 2011-05-11 2018-03-27 Silentium Ltd. Apparatus, system and method of controlling noise within a noise-controlled volume
US9508337B2 (en) * 2013-05-17 2016-11-29 Ask Industries Societa Per Azioni Low-noise fume extractor hood
TWI645116B (zh) * 2017-09-20 2018-12-21 中原大學 風扇噪音控制系統
CN109625260B (zh) * 2017-10-06 2023-06-30 松下电器（美国）知识产权公司 无人飞行体
CN108150753B (zh) * 2018-02-07 2024-09-20 北京市劳动保护科学研究所 一种主被动复合消声器
CN110486927A (zh) * 2018-05-15 2019-11-22 中国船舶重工集团公司第七一一研究所 噪声主动控制设备
CN109545180A (zh) * 2018-11-19 2019-03-29 辽宁工程技术大学 一种变压器有源声屏障降噪系统
CN113470610B (zh) * 2021-06-25 2023-08-22 哈尔滨工业大学（深圳） 噪声控制方法、装置、存储介质和计算机设备

Family Cites Families (16)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1456018A (en) * 1972-11-24 1976-11-17 Nat Res Dev Active control of sound waves
GB1512014A (en) * 1974-06-21 1978-05-24 Univ Leeds Ind Service Ltd Method of attenuating longitudinal compression waves travelling in a gas filled duct
US4473906A (en) 1980-12-05 1984-09-25 Lord Corporation Active acoustic attenuator
FR2550903B1 (fr) 1983-08-19 1986-07-25 Electricite De France Procede et dispositif de commande et de regulation de chaine electroacoustique
GB8404494D0 (en) * 1984-02-21 1984-03-28 Swinbanks M A Attenuation of sound waves
US4665549A (en) * 1985-12-18 1987-05-12 Nelson Industries Inc. Hybrid active silencer
JPS62164400A (ja) * 1986-01-14 1987-07-21 Hitachi Plant Eng & Constr Co Ltd 電子消音システム
GB8603678D0 (en) 1986-02-14 1986-03-19 Gen Electric Co Plc Active noise control
US5511127A (en) * 1991-04-05 1996-04-23 Applied Acoustic Research Active noise control
US5410607A (en) * 1993-09-24 1995-04-25 Sri International Method and apparatus for reducing noise radiated from a complex vibrating surface
US5689572A (en) * 1993-12-08 1997-11-18 Hitachi, Ltd. Method of actively controlling noise, and apparatus thereof
AU1907995A (en) * 1993-12-30 1995-08-01 Bolt Beranek And Newman Inc. Active muffler
US5498127A (en) * 1994-11-14 1996-03-12 General Electric Company Active acoustic liner
US5815582A (en) * 1994-12-02 1998-09-29 Noise Cancellation Technologies, Inc. Active plus selective headset
US5852667A (en) * 1995-07-03 1998-12-22 Pan; Jianhua Digital feed-forward active noise control system
US5828759A (en) * 1995-11-30 1998-10-27 Siemens Electric Limited System and method for reducing engine noise

Also Published As

Publication number Publication date
CA2233253C (fr) 2005-08-16
WO1997016816A1 (fr) 1997-05-09
HK1015923A1 (en) 1999-10-22
FR2740599B1 (fr) 1997-12-19
FR2740599A1 (fr) 1997-04-30
AU719258B2 (en) 2000-05-04
US20030053635A1 (en) 2003-03-20
US7248704B2 (en) 2007-07-24
ATE181444T1 (de) 1999-07-15
DE69602966T2 (de) 1999-12-23
EP0858651A1 (fr) 1998-08-19
AU7498696A (en) 1997-05-22
CA2233253A1 (fr) 1997-05-09
DE69602966D1 (de) 1999-07-22
ES2134645T3 (es) 1999-10-01

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