EP1583075A1 - Dispositif de réduction active de son - Google Patents

Dispositif de réduction active de son Download PDF

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Publication number
EP1583075A1
EP1583075A1 EP04076031A EP04076031A EP1583075A1 EP 1583075 A1 EP1583075 A1 EP 1583075A1 EP 04076031 A EP04076031 A EP 04076031A EP 04076031 A EP04076031 A EP 04076031A EP 1583075 A1 EP1583075 A1 EP 1583075A1
Authority
EP
European Patent Office
Prior art keywords
microphone
loudspeaker
error signal
primary
panel
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP04076031A
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German (de)
English (en)
Inventor
Arthur Perry Berkhoff
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Nederlandse Organisatie voor Toegepast Natuurwetenschappelijk Onderzoek TNO
Original Assignee
Nederlandse Organisatie voor Toegepast Natuurwetenschappelijk Onderzoek TNO
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Nederlandse Organisatie voor Toegepast Natuurwetenschappelijk Onderzoek TNO filed Critical Nederlandse Organisatie voor Toegepast Natuurwetenschappelijk Onderzoek TNO
Priority to EP04076031A priority Critical patent/EP1583075A1/fr
Priority to PCT/NL2005/000234 priority patent/WO2005096269A1/fr
Priority to EP05729401A priority patent/EP1733381B1/fr
Publication of EP1583075A1 publication Critical patent/EP1583075A1/fr
Withdrawn legal-status Critical Current

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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
    • G10K11/1781—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
    • G10K11/1787—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

Definitions

  • the invention relates to a system for actively reducing sound from a primary noise source, such as traffic noise, comprising: a loudspeaker connector for connecting to at least one loudspeaker for generating anti-sound for reducing said noisy sound; a microphone connector for connecting to at least a first microphone placed adjacent to said loudspeaker; a control unit coupled to said first microphone connector, for providing an error signal, based on the output of said first microphone; and a control unit for outputting a signal to said loudspeaker connector, for controlling said loudspeaker based on said error signal of said control unit.
  • a primary noise source such as traffic noise
  • the invention has as one of its goals to provide a system that at the one time offers a compact and robust way of implementing a noise barrier but where the hereabove described disadvantages are mitigated.
  • said simulated error signal of said virtual microphone is a result of a combination of a first transfer function expressing the far field character of the primary source near said first microphone and a second transfer function expressing the near field character of the secondary source near said first microphone.
  • the loudspeaker may be arranged to produce anti-sound in a direction away from said primary noise source. Further, said microphone is preferably placed adjacent in front of said loudspeaker.
  • a second microphone may be placed between said loudspeaker and said primary source.
  • Said second microphone may be arranged to provide a second error signal that is used as a feed forward error signal in order to achieve an expected sound pressure level of the primary source near said loudspeaker.
  • Said at least one loudspeaker and said at least first microphone may be part of an array of loudspeakers and an array of microphones respectively, wherein loudspeakers and said microphones are placed at a distance less than 5 times an interspacing between two adjacent loudspeakers.
  • Such an array may serve as an active noise barrier on the side of a road etc.
  • said at least said at least one loudspeaker and said at least one microphone are part of an array of loudspeakers and an array of microphones respectively, wherein said loudspeakers and said microphones are placed relative to each other in a range between 10% and 100% of an interspacing between two adjacent loudspeakers. It has been found that a position of said microphone at such a general "close" distance of the loudspeaker, is still able to derive a sufficient error signal in order to be able to calculate a far field sound pressure.
  • said microphone may be formed integral with said loudspeaker in a panel to be placed on the side of a road.
  • the invention is also related to a panel for a noise screen to be placed on the side of the road, for actively reducing noise from a primary source, comprising: a loudspeaker to be directed away from the primary source a microphone attached to said panel and placed on a distance away from said panel; and a system according to any of the preceding aspects.
  • said panel may further comprise a second microphone placed opposite to said first microphone, viewed in a direction away from said panel. Furthermore, said loudspeaker is placed on top of said panel. In this way the influence of wind is more or less the same for the primary sources and the secondary sources. This can lead to a more robust system with respect to fluctuations of the wind.
  • the invention is related to a method as described in claims 12 and 13.
  • FIG. 1 A proposed configuration of the system according to the invention can be found in Figure 1.
  • reference sensors 1 microphones are present near secondary sources 2 (loudspeakers), and nearfield error sensors 3 (microphones).
  • nearfield error sensors 3 microphones
  • farfield error sensors 4 microphones
  • One section (n) of the active noise barrier 5 is considered. In order to assess the stability and performance of the active noise barrier 5, including the interactions between different subsystems(n-1, n+1), also the sensors and sources of adjacent sections should be taken into account.
  • virtual error signals are derived from the nearfield error sensors. These virtual error signals should represent the degrees of freedom in the farfield of the angular sector of interest.
  • the primary disturbance d reference signals x
  • actuator control signals u nearfield error signals e _ y
  • farfield error signals e _ z farfield error signals
  • Lower case variables denote vectorial quantities that are a function of time
  • upper case variables denote matrices that operate on the time-dependent vectors.
  • the assumption is that G ux is compensated in the controller, leading to a control structure based on Internal Model Control. Furthermore, aspects related to decentralization are not taken into account yet but will be discussed in the remainder.
  • Figure 2 shows a system using a single transfer function H yz . Such systems are used for actively controlling noise from panels. However, the performance for the present application is insufficient, as can be demonstrated in simulations.
  • Figure 3 shows a system where the basic strategy is to minimize the nearfield pressure, using a feedforward controller, as in Figure 2.
  • Figure 4 shows a system in which the nearfield pressure is directly fed back to the controller, where the basic strategy is also to minimize the nearfield pressure. The latter configuration has been tested by Japanese researchers. In the present application, reduction of the nearfield pressure is very different from minimizing the farfield pressure.
  • the simulations described below will show that the configuration of Figure 5 performs substantially better than the configurations of Figure 2-4.
  • a transfer function H yz is designed which makes a real-time estimate of e_z from measured data e_y .
  • the maximum performance with such a transfer function is limited by the fact that we are dealing with two sets of sources, the primary sources and the secondary sources. These two sets of sources may have a very different nature and may lead to rather different requirements for the transfer function H yz .
  • One big difference, for example, is that the nearfield sensors are located rather far away from the primary sources while the nearfield sensors are, by definition, in the nearfield of the secondary sources. So, although a single transfer function H yz may have acceptable performance in some systems, such as active panels, the performance for active noise barriers can be improved further.
  • G dy the transfer function between primary source and nearfield error sensor
  • G dz the transfer function between primary source and farfield error sensor
  • G uy the transfer function between secondary source and nearfield error sensor
  • G uz the transfer function between secondary source and farfield error sensor.
  • Stability robustness and performance robustness are governed by the sensitivity of the control system to changes in the secondary path.
  • the propagation distances involved in the secondary path are considerably reduced if nearfield sensors are used instead of the farfield sensors. Therefore, it is expected that the reduced change of the propagation path will have a positive effect on the stability robustness of the system.
  • the primary sources are effectively diffraction sources on top of a noise barrier and if the secondary sources are close to these diffraction sources then we obtain a system in which a large part of the possibly varying transmission path is common to both the primary signals and the secondary signals. This results in an expected improved performance robustness with respect to changes in wind, temperature, etc.
  • an initial calibration phase is assumed in which sources are placed at random positions in the region where the primary noise sources are to be expected.
  • the estimate of the primary signal on one of the farfield sensors is shown in Figure 8.
  • the estimate of one of the secondary source transfer functions to the farfield as estimated from the secondary transfer functions to the nearfield sensors is shown in Figure 9.
  • calibration sources have been used, which are indicated as green asterixes in Figure 12.
  • Three independent primary sources are used, also shown in Figure 12. The identification procedure is based on the solution of the equations resulting from an assumed multi-input, multi-output Finite Impulse Response model leading to a block-Toeplitz structure.
  • This value of ⁇ was obtained by reducing the value of ⁇ until the prediction error for primary signal validation data did not reduce anymore.
  • the latter prediction error was obtained with validation data from an independent set of primary sources at random positions in the same region as for the solution of the system of equations.
  • the example of Figure 10 is an active noise barrier in which the error signal equals the pressure as measured on microphones near the secondary sources.
  • this distance i.e. the difference between the z-coordinate of the 5 secondary sources and z-coordinate of the 5 error sensors is 0.5 m.
  • 5 reference sensors are used, which are positioned, as seen from the secondary sources, 1 m towards the primary sources.
  • the primary noise sources are three independent broadband noise sources which are positioned at a distance of 4.5 m from the secondary sources.
  • Figure 10 shows the configuration and the resulting sound pressure in the x,z-plane. It can be seen that sound pressure reductions are mainly obtained near the error sensors. The reduction at the error sensors is 24.2 dB but the reduction in the farfield is much less, being 1.9 dB.
  • Figure 12 shows the results in case the error signal equals virtual farfield signals, using the same microphone positions as in Figure 10.
  • the virtual sensor signals are obtained by processing the nearfield error signals e_y with a fixed operator which is determined in a calibration phase.
  • the sources as used in this calibration phase are positioned in the region where the primary noise sources are to be expected (see Figure 12). It can be seen that the resulting farfield sound pressure reductions are slightly less than in Figure 11, being 9.0 dB. However, the farfield sound pressure reductions are considerably higher than obtained with the nearfield error sensors as used in Figure 10.
  • the reduction of the error signals is approximately equal in case of minimizing the virtual error signals, being 11.6 dB, and in case of minimizing the true farfield error signals (11.3 dB).
  • the performance of the systems with 32 and 64 coefficients is less dependent on the actual primary source distribution and is therefore more stable and predictable.
  • the influence of a simultaneous change of the positions of the primary sources and a changing primary spectrum was investigated using a modified primary spectrum that was obtained by applying a fourth-order bandpass filter with Butterworth characteristic with lower and upper cutoff frequencies of 0.15 f s and 0.35 f s , respectively, to the primary source signals.
  • a slight improvement was found of the performance on the farfield evaluation microphones from 10.6 dB to 11.4 dB.
  • the performance for a moving source was investigated.
  • the radiation characteristics of the moving sources were simulated by taking into account the doppler shift as well as the changing radiation characteristics depending on the direction of the movement. Also, simulations were performed in order to study the performance variations for a change in the height of the primary sources.
  • the invention is not limited to the hereabove described embodiments but may comprise variations and modifications thereto while falling under the scope of the annexed claims.

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  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Acoustics & Sound (AREA)
  • Multimedia (AREA)
  • Soundproofing, Sound Blocking, And Sound Damping (AREA)
EP04076031A 2004-03-31 2004-03-31 Dispositif de réduction active de son Withdrawn EP1583075A1 (fr)

Priority Applications (3)

Application Number Priority Date Filing Date Title
EP04076031A EP1583075A1 (fr) 2004-03-31 2004-03-31 Dispositif de réduction active de son
PCT/NL2005/000234 WO2005096269A1 (fr) 2004-03-31 2005-03-31 Systeme pour reduction sonore
EP05729401A EP1733381B1 (fr) 2004-03-31 2005-03-31 Systeme pour reduction sonore

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
EP04076031A EP1583075A1 (fr) 2004-03-31 2004-03-31 Dispositif de réduction active de son

Publications (1)

Publication Number Publication Date
EP1583075A1 true EP1583075A1 (fr) 2005-10-05

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EP04076031A Withdrawn EP1583075A1 (fr) 2004-03-31 2004-03-31 Dispositif de réduction active de son
EP05729401A Not-in-force EP1733381B1 (fr) 2004-03-31 2005-03-31 Systeme pour reduction sonore

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EP (2) EP1583075A1 (fr)
WO (1) WO2005096269A1 (fr)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP3125237A1 (fr) * 2015-07-29 2017-02-01 Harman International Industries, Incorporated Appareil d'annulation active du bruit et procédé d'amélioration de performances de la reconnaissance vocale
EP3185240A1 (fr) * 2015-12-22 2017-06-28 Helmut-Schmidt-Universität Système et procédé permettant de réduire activement le bruit passant à travers une ouverture dans une barrière sonore

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5315661A (en) * 1992-08-12 1994-05-24 Noise Cancellation Technologies, Inc. Active high transmission loss panel
US5519637A (en) * 1993-08-20 1996-05-21 Mcdonnell Douglas Corporation Wavenumber-adaptive control of sound radiation from structures using a `virtual` microphone array method
EP0759606A2 (fr) * 1995-08-21 1997-02-26 DIGISONIX, Inc. Système de commande actif, adaptatif et sélectif
US5917919A (en) * 1995-12-04 1999-06-29 Rosenthal; Felix Method and apparatus for multi-channel active control of noise or vibration or of multi-channel separation of a signal from a noisy environment
US20030002687A1 (en) * 1999-11-16 2003-01-02 Andreas Raptopoulos Apparatus for acoustically improving an environment and related method

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5315661A (en) * 1992-08-12 1994-05-24 Noise Cancellation Technologies, Inc. Active high transmission loss panel
US5519637A (en) * 1993-08-20 1996-05-21 Mcdonnell Douglas Corporation Wavenumber-adaptive control of sound radiation from structures using a `virtual` microphone array method
EP0759606A2 (fr) * 1995-08-21 1997-02-26 DIGISONIX, Inc. Système de commande actif, adaptatif et sélectif
US5917919A (en) * 1995-12-04 1999-06-29 Rosenthal; Felix Method and apparatus for multi-channel active control of noise or vibration or of multi-channel separation of a signal from a noisy environment
US20030002687A1 (en) * 1999-11-16 2003-01-02 Andreas Raptopoulos Apparatus for acoustically improving an environment and related method

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
GARCIA-BONITO J ET AL: "GENERATION OF ZONES OF QUIET USING A VIRTUAL MICROPHONE ARRANGEMENT", JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA, AMERICAN INSTITUTE OF PHYSICS. NEW YORK, US, vol. 101, no. 6, 1 June 1997 (1997-06-01), pages 3498 - 3516, XP000696885, ISSN: 0001-4966 *

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP3125237A1 (fr) * 2015-07-29 2017-02-01 Harman International Industries, Incorporated Appareil d'annulation active du bruit et procédé d'amélioration de performances de la reconnaissance vocale
CN106409280A (zh) * 2015-07-29 2017-02-15 哈曼国际工业有限公司 用于改进语音识别性能的有源噪声消除设备和方法
US9704509B2 (en) 2015-07-29 2017-07-11 Harman International Industries, Inc. Active noise cancellation apparatus and method for improving voice recognition performance
EP3185240A1 (fr) * 2015-12-22 2017-06-28 Helmut-Schmidt-Universität Système et procédé permettant de réduire activement le bruit passant à travers une ouverture dans une barrière sonore

Also Published As

Publication number Publication date
EP1733381B1 (fr) 2012-12-19
EP1733381A1 (fr) 2006-12-20
WO2005096269A1 (fr) 2005-10-13

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EP1583075A1 (fr) Dispositif de réduction active de son

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