Classifications

• • 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
  • G10K11/1781—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 characterised by the analysis of input or output signals, e.g. frequency range, modes, transfer functions
  • G10K11/17813—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 characterised by the analysis of input or output signals, e.g. frequency range, modes, transfer functions characterised by the analysis of the acoustic paths, e.g. estimating, calibrating or testing of transfer functions or cross-terms
  • G10K11/17817—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 characterised by the analysis of input or output signals, e.g. frequency range, modes, transfer functions characterised by the analysis of the acoustic paths, e.g. estimating, calibrating or testing of transfer functions or cross-terms between the output signals and the error signals, i.e. secondary path
• • 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
  • G10K11/1781—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 characterised by the analysis of input or output signals, e.g. frequency range, modes, transfer functions
  • G10K11/17821—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 characterised by the analysis of input or output signals, e.g. frequency range, modes, transfer functions characterised by the analysis of the input signals only
  • G10K11/17825—Error signals
• • 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
  • G10K11/17853—Methods, e.g. algorithms; Devices of the filter
  • G10K11/17854—Methods, e.g. algorithms; Devices of the filter the filter being an adaptive filter
• • 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
• • 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
• • 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
  • G10K2210/12—Rooms, e.g. ANC inside a room, office, concert hall or automobile cabin
• • 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
  • G10K2210/3053—Speeding up computation or convergence, or decreasing the computational load

Definitions

• the present invention relates to methods and devices for active soundproofing. More particularly, the invention relates to a method for soundproofing a space receiving noise, by emitting noise in said space.
• the document EP-A-0 601 934 describes an example of such a method, in which: - the noises to be attenuated are captured outside the space to be soundproofed, by means of microphones, the noises are calculated during the propagation of the noises towards the space to be soundproofed, then said noises are emitted so that they arrive in said space to be soundproofed at the same time as the noises to be attenuated.
• the process described in this document is satisfactory, in particular for attenuating random noises such as those coming from the street, but it nevertheless has the disadvantage that the counter noises must be calculated and emitted extremely quickly before the noises to be attenuated reach the space to be soundproofed, which limits the volume of the calculations made to determine the noise abatements, and therefore the quality of the soundproofing.
• the object of the present invention is in particular to overcome this drawback, when the noises to be attenuated are emitted by an electric sound generating apparatus such as a radio, television receiver, a hi-fi system, or the like.
• a method of the kind in question is essentially characterized in that an electrical signal known as a reference signal, used read by an electrical sound generator which transforms this reference electrical signal into sound waves at the origin of at least part of the noise to be attenuated, this acquisition being carried out directly by electromagnetic means (for example, direct acquisition of the electrical signal by wire, acquisition by capturing a wave, radio or light, modulated as a function of the reference signal, or others) at the latest when the electric sound generating apparatus transforms said electric reference signal into sound waves, and what one determines the noises according to this electrical reference signal.
• electromagnetic means for example, direct acquisition of the electrical signal by wire, acquisition by capturing a wave, radio or light, modulated as a function of the reference signal, or others
• the signal which is used to determine the noises is acquired at the latest when the noises are emitted, whereas in the methods of the prior art, this signal was acquired by transducers, for example microphones, that after the sound waves at the origin of the noises have already traveled a certain distance: the invention avoids this delay in acquiring the reference signal used to determine the noises, which makes it possible to have more time to determine said counter noises, and therefore to use a process for preparing said noises which is finer and more efficient than in the subsequent art.
• the counter-noises are emitted by means of a non-zero number n high -speakers, and the noise countermeasures are also determined as a function of data relating to the propagation of sounds, on the one hand, between the electrical sound generating apparatus and the space to be soundproofed, and on the other hand, between the loudspeakers and the space to be soundproofed;
• h ⁇ :, (- t) represents the time feedback of the impulse response h 1D (t), previously determined and stored, between the speaker i and a predetermined point j called "calibration" belonging to the space to be soundproofed, the space to be soundproofed comprising a non-zero number p of calibration points
• the impulse response h 1D (t) corresponding to the acoustic signal received at point j when the loudspeaker i emits a short acoustic pulse
• g D (t) is the impulse response, previously determined and stored, between the sound-generating electrical apparatus and the calibration point j, this impulse response g ** (t) corresponding to the acoustic signal received at the calibration point j when the electric sound generator emits a short acoustic pulse
• S (t) is an estimate of the acoustic signal emitted by the electric sound generating apparatus, this estimate being determined as a function of the reference electric signal, and ⁇ £> denotes the convolution product;
• S (t) is expressed in the form As (t), where A is a constant coefficient at least by periods and s (t) is a signal determined directly from the electric signal reference point, and the noise in the space to be soundproofed is measured to determine the coefficient A; the coefficient A is determined by a process of minimizing the noise in the space to be soundproofed.
• the subject of the invention is also a device for implementing a method as defined above, this device comprising: an electromagnetic acquisition system for acquiring the reference electrical signal, - a electronic central unit which is connected electromagnetically (radio link, electric wire link, fiber optic link, or the like) to the acquisition system and which is suitable for determining noise abatements, - and a non-zero number n of loudspeakers which are connected to the electronic central unit to emit the noise towards the space to be soundproofed.
• the device comprises the electrical sound generating apparatus, and the device d acquisition is integrated into this electrical appliance;
• the electrical sound generator is adapted to generate the sound waves corresponding to the reference electrical signal with a certain delay with respect to the acquisition of said reference electrical signal by the acquisition device; - said delay is between 0.01 and 2 seconds;
• the sound generating electrical apparatus also generates images, with the same delay as for the generation of said sound waves;
• the acquisition device is connected to the electrical sound generator;
• the electrical sound generating apparatus is a receiver adapted to receive said reference electrical signal on a reception channel from a number of predetermined reception channels, the acquisition device itself being a receiver which is independent of said electrical apparatus sound generator and which is adapted to receive an electrical signal on a reception channel among said predetermined reception channels, the device further comprising means for selecting the reception channel on which the reference electrical signal is received;
• the device further comprises at least one microphone which is adapted to receive the noises generated by the
• FIG. 1 is a diagrammatic view illustrating a first embodiment of the invention
• FIG. 2 is a diagrammatic view of the electrical sound generator apparatus for which noise is sought to be reduced, in a second embodiment embodiment of the invention
• FIG. 3 is a schematic view similar to FIG. 1, illustrating a third embodiment of the invention.
• the same references designate identical or similar elements.
• the electrical sound generating device is a television receiver, but it could be any other electrical device which transforms an analog or digital electrical signal, known as the reference electrical signal, into sound waves at the origin at least some of the noise that we are trying to reduce in space 1.
• the electrical sound generating device could also be constituted by a radio receiver, an optical disc player, a microgroove disc player, a magnetic tape player (presented or not in the form of a cassette), a loudspeaker receiving by wire or other means the signal to be broadcast, etc., or a combination of these.
• the electrical sound generating appliance whose noise is sought to be attenuated is generally located in another room 5 of the same building 3 as space 1, but this appliance could also be located outside of building 3, for example when trying to attenuate the noises coming from a street sound system or an outdoor concert sound system.
• the space 1 to be soundproofed could if necessary be located outside a building.
• the soundproofing of the space 1 is carried out by generating in this space counter-noise, in phase opposition with the noise coming from the electrical apparatus 4 generating sounds.
• noises are generated by a number n, at least equal to 1 and generally at least equal to 2, of loudspeakers 6 controlled by an electronic central unit 7, which generally consists of a computer connected by wire or wireless to the high -speakers 6 by means of analog-digital converters integrated for example into said computer.
• the computer 7 is also connected electromagnetically to the sound generating electrical device 4, so as to receive from this device the above-mentioned reference electrical signal.
• This electromagnetic link can be made by wire (point-to-point link or home automation bus, by solid cable, by coaxial cable or by optical fiber) or by radio, as in the example shown in FIG. 1.
• the computer 7 is connected to a radio receiver 8 while a radio transmitter 9 is connected to the television 4, for example by means of the audio output or the "Scart" socket of this television. or any other interface, for transmitting the reference electrical signal to the receiver 8 and the computer 7.
• the computer 7 Given the fact that the acquisition and transmission of the reference electrical signal by electromagnetic means is almost instantaneous in comparison with the propagation of the sound, the computer 7 thus knows the reference signal s (t) corresponding to the emitted sound signal by the electric sound generator 4, well before this sound signal reaches room 2. The computer 7 thus has maximum time to optimally assess the noise to be emitted by the various speakers 6.
• This determination of the noises can be carried out by any known means, for example by adaptive filtering for example as taught in the document EP-A-0 505 949 (see FIG. 16 of this document, where the signal s (t) would be applied to the circuit in place of the signal from the microphone 25 of said FIG. 16), or according to a method similar to the method taught in document EP-A-0 601 934. ⁇
• the impulse responses h ⁇ ;) (t) and g-- (t) can be measured for example by placing a microphone 11 successively at the different calibration points 10 (or by placing several microphones simultaneously at the different points 10) and by transmitting the aforementioned acoustic pulses by the loudspeakers 6, and from the location of the electric sound generating apparatus 4, this microphone 11 being connected to the computer 7 by wire or wireless, by means of an analog converter- digital integrated into said computer so that the impulse responses can be acquired and stored by the computer 7.
• the computer 7 then sends a signal from each speaker i where: h ⁇ ;) (-t) represents the time return of the impulse response h 1D (t),
• S (t) is an estimate of the acoustic signal emitted by the sound-generating electrical device, this estimate being determined as a function of the reference electrical signal s (t), and ® denotes the convolution product.
• f (t) the convolution product of a function f (t) by a function g (t) is worth:
• the computer 7 In order to evaluate the coefficient A, it is possible for example to leave the microphone 11 (or more microphones) permanently in the space 1 to be soundproofed, and the computer 7 gradually varies the coefficient A so as to minimize the noise perceived by said microphone.
• This minimization process can be implemented continuously or at close time intervals by the computer 7, or even when the microphone 11 measures a noise level above a determined threshold, in the case where the use of the device 4 would have changed the volume of this device. If necessary, the coefficient A (or the estimate S (t)) could be transmitted by the transmitter 9 from data acquired directly in the device 4.
• the radio transmitter 9 ′ or any other device for acquiring the reference electrical signal s (t), could be integrated into the electric sound generator 4 which would then be an integral part of the active soundproofing device according to the invention.
• the electrical sound generator 4 can be adapted to generate the sound waves corresponding to the reference electrical signal with a certain delay with respect to the acquisition of said signal by the transmitter 9, this delay possibly being for example between 0.01 and 2 seconds: it is thus possible to give additional time to the computer 7 to optimally determine the noise to be emitted by the different speakers 6.
• the device 4 also generates images, such as in the case of a television receiver, it generates these images with the same delay as for sound waves.
• the electrical sound generator 4 is a radio or television receiver, or more generally any device adapted to receive the electrical signal reference s (t) on a reception channel among a certain number of predetermined reception channels, it is possibly possible to avoid connecting or integrating with this apparatus 4 a special device for acquiring the reference electric signal.
• an acquisition device 12 is used, consisting of a receiver which is independent of the receiver 4 and which is connected to the computer 7.
• This receiver 12 is similar to the receiver 4, and it is adapted to receive electrical signals on the same reception channels as the receiver 4.
• the receiver 12 can for example be controlled by the computer 7, so as to scan the various reception channels, the computer 7 then comparing the electrical signals thus received with the electrical signals coming from the microphone 11.
• the computer 7 can select a reception channel, on which the electrical signal closest to the signal from the microphone is received, the electrical signal s (t) received on this reception channel being then used by the computer 7 as an electrical reference signal.
• This process can be implemented at regular time intervals by the computer 7, or when the noise level measured by the microphone 11 exceeds a certain threshold, in the case where the user of the receiver 4 has changed the reception channel.
• noise emitted according to the invention could be superimposed on the noise calculated according to the prior art from measurements made by microphones located inside the space 1, to attenuate the noises other than those generated by the electrical sound generator 4.

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• Physics & Mathematics (AREA)
• Engineering & Computer Science (AREA)
• Acoustics & Sound (AREA)
• Multimedia (AREA)
• Soundproofing, Sound Blocking, And Sound Damping (AREA)
• Measurement Of Mechanical Vibrations Or Ultrasonic Waves (AREA)
• Noise Elimination (AREA)

Applications Claiming Priority (3)

Publications (1)

Family

ID=9513652

Family Applications (1)

Country Status (5)

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Family Cites Families (4)

• 1997
  • 1997-11-21 FR FR9714653A patent/FR2771541B1/fr not_active Expired - Fee Related
• 1998
  • 1998-11-19 JP JP2000522581A patent/JP2001524701A/ja active Pending
  • 1998-11-19 AU AU12446/99A patent/AU1244699A/en not_active Abandoned
  • 1998-11-19 WO PCT/FR1998/002468 patent/WO1999027520A1/fr not_active Application Discontinuation
  • 1998-11-19 EP EP98955694A patent/EP1032932A1/de not_active Withdrawn

Non-Patent Citations (1)

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