WO2016083513A1 - Procédé et système de suppression active de son - Google Patents

Procédé et système de suppression active de son Download PDF

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Publication number
WO2016083513A1
WO2016083513A1 PCT/EP2015/077787 EP2015077787W WO2016083513A1 WO 2016083513 A1 WO2016083513 A1 WO 2016083513A1 EP 2015077787 W EP2015077787 W EP 2015077787W WO 2016083513 A1 WO2016083513 A1 WO 2016083513A1
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WO
WIPO (PCT)
Prior art keywords
sound
fast
sound source
primary
sources
Prior art date
Application number
PCT/EP2015/077787
Other languages
German (de)
English (en)
Inventor
Uli Krause
Delf Sachau
Original Assignee
Helmut-Schmidt-Universität
Hamburg Innovation Gmbh
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 Helmut-Schmidt-Universität, Hamburg Innovation Gmbh filed Critical Helmut-Schmidt-Universität
Publication of WO2016083513A1 publication Critical patent/WO2016083513A1/fr

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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
    • G10K11/1785—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
    • G10K11/1787—General system configurations
    • G10K11/17875—General system configurations using an error signal without a reference signal, e.g. pure feedback

Definitions

  • the present invention relates to a method for actively suppressing sound from a plurality of primary sound sources by means of sound from a plurality of secondary sound sources, wherein each secondary sound source is assigned exactly one primary sound source, and a system for active suppression of sound by a method according to the invention.
  • Active sound suppression systems and methods also referred to as antinoise systems or noise reduction systems and methods, typically employ one or more secondary sound sources or secondary sound sources to reduce the primary sound radiated from one or more noise sources referred to as the primary sound source or sources Speakers, one or more sensors and a control device which is connected to the speakers and the sensors.
  • the control device controls the loudspeakers on the basis of the signals supplied by the sensors in such a way that the entire sound field generated by the combination of the primary sound source (s) and the loudspeakers is favorably influenced in terms of the target of the sound reduction.
  • one or more sensors can be used to generate reference signals, on the basis of which control signals for the secondary sound sources are determined, and one or more further sensors can serve as error sensors, with the aid of which the quality of the control signals is checked and their determination is adjusted as needed ,
  • the desired influence of the sound field can be based on various physical mechanisms.
  • sound is reflected at the locations of the secondary sound sources, that sound is absorbed by the secondary sound sources and the sound energy is transmitted via the corresponding sound sources.
  • tuatoren is dissipated or that the primary sound sources and the secondary sound sources influence each other in such a way that the radiated from the combination of primary and secondary sound sources total sound power is minimized.
  • the interference affects a reduction in the ability of sound sources to emit sound.
  • the secondary sound sources reduce the effective resistance of the primary sound source by acting on the acoustic modes of the sound field or act on the air molecules located in front of the primary sound source, that they less resistance to the movement of the radiation surface of the primary sound source , There is always the difficulty that the contribution of the secondary sound sources to the sound field must not overcompensate the benefits achieved in a negative way.
  • one known type of active noise reduction employs one or more error microphones as sensors, each of which locally measures the sound pressure produced by all existing sound sources, including the primary sound source and one or more secondary sound sources.
  • the measurement results are processed by the control device, which then controls the secondary sound sources in such a way that the sound pressure at the microphones is minimized as far as possible by destructive interference and / or sound reflection at the locations of the secondary sound sources.
  • This can be a local noise reduction can be achieved at the microphone positions.
  • This principle which is an example of a sound pressure-based control, has the disadvantage that the local noise reduction at the microphone positions is generally accompanied by a noise amplification in other areas. Furthermore, only the local sound effect in the form of the sound pressure is influenced, without the cause in the form of sound pressure. power radiation through the primary sound source to combat.
  • the microphones must also be distributed globally and the secondary sound sources must be arranged so that they can excite the same modes as the primary sound source. It is also problematic to take into account changing environmental influences in the implementation of the control. Further, because the microphones measure the overall sound pressure, these methods may fail in the presence of additional sources of noise since the controller can not account for the contribution of the various sound sources. Despite these drawbacks, controls based on sound pressure measurements are most commonly used because the necessary measurements are technically easy to implement.
  • the radiated total active power of a pair of sound source from a primary source and a secondary source is minimal if and only if the secondary source is driven in phase or phase opposition, or equal in relation to the primary source - or antiphase oscillates, and the secondary source does not radiate active sound power.
  • the effective sound power is the real part of the overall sound power usually represented by a complex size and corresponds to the actual net energy transport per second perpendicular to an area, such as the emission surface of a sound source. le.
  • the dummy sound power represented by the imaginary part of the total sound power is due to the energy transport through the medium mass, which is merely moved, but not compressed.
  • the secondary source is driven either with a control signal for the primary source in the same or opposite phase (in the case of the former document) or an opposite in relation to the drive signal for the primary source drive signal (in the case of the latter document), so that can not be dispensed with the design uniformity, and the amplitude of the drive signal for the secondary source is set manually.
  • the sensors used are either a large number of microphones randomly distributed in space or a sound intensity sensor comprising two microphones spaced apart from each other. This means a relatively high amount of hardware.
  • EP 2 378 513 A1 discloses a system and a method for active suppression of sound from a primary sound source by means of a secondary sound source.
  • the method described there can also be used for active sound suppression of a plurality of primary sound sources by a plurality of secondary sound sources, wherein each primary sound source is assigned exactly one secondary sound source.
  • each primary sound source is assigned exactly one secondary sound source.
  • EP 2 378 513 A1 requires a one-time pre-equalization to adapt the acceleration or speed of the secondary sound sources. It is assumed that a time invariance of the primary sound sources and a sound transmission without external interference. In the long-term operation of the secondary sound sources, however, a phase relationship between the vibrations of the primary sound sources and the secondary sound sources, for example, by a vibro-acoustic interaction between the primary and secondary sound sources, change.
  • the present invention achieves this object with a method of actively canceling sound from a plurality of primary sound sources by means of sound from a plurality of secondary sound sources, each secondary sound source being associated with exactly one primary sound source.
  • a control amount for the secondary sound source is determined iteratively by the steps of determining a speed of each primary sound source Determining a speed and a sound pressure of each secondary sound source, determining a speed to be effectively suppressed for each secondary sound source, wherein the speed of a secondary sound source to be effectively suppressed next to the speed determined for the primary sound source associated with the secondary sound source concerned also includes the sound pressure and the speed determined for all the secondary sound sources except for the secondary sound source concerned, and determining the control value for each secondary sound source such that minimizing a difference between the fast suppression rate to be effectively suppressed for a secondary sound source and the rapid rate determined for the secondary sound source.
  • the secondary sound sources are controlled with the respectively determined control variables.
  • the plurality of primary sound sources may be different sound sources, each emitting separate sound.
  • the plurality of primary sound sources are so-called elementary sound sources, into which a real sound source is thoughtfully decomposed, when the real sound source emits sound with different phases and / or in different directions.
  • the secondary sound sources may be loudspeakers, and a secondary sound source may also be formed by a plurality of loudspeakers, which are all located at the same location and are controlled in the same way by the data processing device.
  • Each of the secondary sound sources is assigned exactly one primary sound source. The number of primary sound sources whose sound is actively suppressed is thus less than or equal to the number of secondary sound sources.
  • a primary sound source can thus also be assigned to a plurality of secondary sound sources.
  • the number of primary sound sources is greater than the number of secondary sound sources.
  • a primary sound source which is not dominant in relation to the other primary sound sources, need not necessarily be suppressed.
  • each primary sound source whose sound is to be actively suppressed, is assigned at least one secondary sound source.
  • the secondary sound sources are controlled with manipulated variables which are determined iteratively, ie in several successive steps, such that the sound of the plurality of primary sound sources is actively suppressed and the sound intensity of the sound emitted by the secondary sound sources becomes minimal, but not negative, ie is reduced to zero, and is preferably zero. If the sound intensity of the secondary sound sources becomes negative, the sound of the primary sound sources is absorbed and suppression of the sound of the primary sound sources can be achieved by maximizing the absorption. Since in the following all calculations are carried out in the frequency domain, ie with measured signals that have been Fourier-transformed from the time domain into the frequency domain, the dependence of the different quantities is not given by the time t but by the frequency k.
  • a fast or sonic fast is determined for each sound source.
  • the determination of a sound velocity does not necessarily mean that the actual sound velocity is actually determined.
  • the term fast in the sense of the present patent application includes not only the actual sound velocity, but also directly with these related variables, such as acceleration or acceleration of sound.
  • an acceleration sensor which is arranged directly on the oscillating sound source, for example a diaphragm of a loudspeaker.
  • a laser sensor with which an oscillating movement of a surface of a sound source is detected, wherein from the detected movement an acceleration or a rapid of the sound can be determined.
  • the secondary sound sources are controlled with the control variables determined in this way.
  • the difference between the speed of the secondary sound sources and the speed to be effectively suppressed is advantageously reduced and thus the sound emitted by the primary sound sources is suppressed.
  • the sound intensity of the secondary sound sources is also reduced to zero.
  • the interaction of the sound sources with each other is taken into account by the calculation of a fast to be suppressed by the respective secondary sound sources, taking into account the remaining secondary sound sources.
  • the fast to be effectively suppressed are determined on the assumption that the sound intensity of each secondary sound source is zero. This assumption has been found to be particularly advantageous to account for interactions between the various secondary sound sources while minimizing the total radiated sound energy to zero. This creates an altogether less loud procedure.
  • the use according to the invention of a transmission path matrix makes it possible to calculate the sound pressure of the secondary sound sources from the speeds determined for the secondary sound sources.
  • the transmission line matrix H pa (fc) takes into account that the rapid and the sound pressure of the secondary sound source are not measured at the same location.
  • the speed of a secondary sound source is measured directly on a diaphragm of a loudspeaker, for example by means of a laser sensor or a Hall probe, while the sound pressure is measured by means of a microphone which is arranged at a distance from the diaphragm.
  • the transmission path matrix is thus an empirical quantity which describes a system of secondary sound sources and measuring devices and which, once measured, can be stored permanently in a device for carrying out the method according to the invention.
  • Pps (fc) Ps (f) - H pa (fc) a s (fc) Equation (4) can be determined, where p s (fc) is the certain secondary sound pressure.
  • a measured transmission distance matrix which is not only determined by the theoretical model, will be referred to below as H TM a .
  • the sound pressure P p " s (fe) generated at the measurement location by the primary sound sources is based on the variables measured or determined with real sensors
  • the transmission link matrix for each secondary sound source comprises a factor for correcting a phase difference between the sound pressure determined for a secondary sound source and the speed determined for the relevant secondary sound source.
  • the factor according to the invention can be advantageously, for example, a transit time difference from a sound source Compensate for the different sensors, phase differences due to deviating quality of the sensors or phase differences due to different measurement methods in the determination of a sound pressure and a fast.
  • the use of a factor for correcting a phase difference has been found to be particularly advantageous in the practical implementation of the method in order to actively actively suppress the sound generated by the primary sound source.
  • acceleration sensors with the same measurement principle are used to detect the fast of the primary and the secondary sound sources. Therefore, it is not necessary to compensate for a phase difference at the particular speeds because there is no phase difference between the sensors.
  • sensors with different measurement principles are used in determining the fastness of the primary and secondary sound sources, a phase correction corresponding to equation (6b) would be necessary.
  • Equation (7) in [diag ⁇ ps (fc) ⁇ a- (fc) * ], where the subscript sol denotes the solution of a system of equations and the upper index c denotes the correction around the phase error. It should be noted, however, that equation 7 only leads to a unique solution for ic (fc) if, as in a preferred embodiment, the number of secondary sound sources equals the number of primary sound sources. On the other hand, if several secondary sound sources are assigned to a primary sound source, then the equation system (7) is overdetermined, provided that the secondary sources, which are assigned to exactly one primary source, are located at the same location and a solution for the factor K (C) can be used, for example an optimization process can be found. Possible solutions for overdetermined equation systems are well known to the person skilled in the art.
  • a Filtered-Reference-Least-Mean-Square algorithm for the iterative determination of the manipulated variables.
  • a reference in the Filtered-Reference least-mean-square algorithm an image of a fast one of the primary sound sources is used. The mapping takes place by means of a manipulated variable transmission matrix with which it can be determined which fast are generated by the secondary sound sources as a function of the manipulated variables.
  • FxLMS Filtered-Reference Least-Mean Square
  • W u + 1 (k) W u (k) - (kX (ky (to be determined H TM (fc)) "e (fe) Equation (8), wherein w u in the previous step determined u manipulated variable, is an Is the weight with which the convergence speed of the filter can be set, X (Ji) is a reference, for example a quick one of the primary sources, the superscript H denotes an adjoint, ie complex conjugate and transpose, matrix and H TM denotes the manipulated variable transmission matrix ,
  • each primary sound source is assigned exactly one secondary sound source.
  • This preferred embodiment of the method according to the invention is particularly economical, since the number of secondary sound sources and sensors required is minimal.
  • the object underlying the invention is achieved by a system for active suppression of sound with a method according to one of the preceding embodiments.
  • the system includes a plurality of sound pressure sensors, a plurality of primary speed sensors, a plurality of secondary speed sensors, a plurality of secondary sound sources, and a data processing device.
  • the sound pressure sensors, the fast sensors and the secondary sound sources are functionally connected to the data processing device.
  • the system is designed to determine the speed of the primary sound sources using the primary fast sensors.
  • the system is further adapted to determine the sound pressure of the secondary sound sources by means of the sound pressure sensors.
  • the system is configured to determine the speed of the secondary sound sources by means of the secondary speed sensors.
  • the data processing device is configured to determine from the determined rapid and acoustic pressure manipulated variables for the secondary sound sources with a method according to one of the preceding preferred embodiments and to control the secondary sound sources with the specific manipulated variables.
  • the system according to the invention comprises the means necessary for carrying out the inventive method.
  • the step of determining can already be carried out directly by the sensors, which measure a quantity on the basis of which the respective value is determined.
  • the sensors send only one measured value to a data processing device, which is evaluated in this to determine the required value or the required size.
  • the data processing device may be, for example, a conventional computer or an integrated circuit.
  • a data processing device can be set up for carrying out method steps, for example by uploading software, but also by means of corresponding hardware-related measures. Also, the data processing device can be formed by a plurality of separate data processing devices.
  • one of the fast sensors is a laser sensor.
  • Laser sensors enable an essentially instantaneous measurement of the acceleration of a sound source and thus the speed of the sound generated by the sound source, without the need for a sensor to be attached directly to the sound source.
  • a laser sensor for measuring a speed of a primary sound source can be arranged in a housing of a system according to the invention and measure the acceleration from a distance to the primary sound source. This eliminates the need for modifications to the primary sound source for mounting sensors.
  • At least one of the fast sensors is a Hall probe.
  • a Hall probe is a particularly inexpensive embodiment of an acceleration sensor that can be used to determine a speed of a sound source.
  • At least one of the sound pressure sensors is a microphone. It is further preferred that the transmission path matrix and / or the manipulated variable transmission matrix are permanently stored in a memory of the data processing device. Thus, with a permanent arrangement of the system, this can be operated at any time without the need for previous measurements for adjusting the system. Finally, it is preferred if a number of the sound pressure sensors, the primary speed sensors, the secondary speed sensors and the secondary sound sources are the same.
  • Fig. 3 is a schematic representation of an embodiment of a secondary sound source.
  • the method illustrated in FIG. 2 requires three different input variables: a fast a TM (t) of a plurality of primary sound sources 3, a fast a TM (t) of a plurality of secondary sound sources 5, 21 and a sound pressure p TM (£) of one A plurality of secondary sound sources 5, 21.
  • the input variables have previously been determined from the signals measured with the respective sensors 7, 9, 11, 25. All input variables are Fourier-transformed before performing the further method steps in the frequency domain, as indicated by the symbols indicated by the reference numeral 27.
  • the number of primary sound sources 3 corresponds to the number of secondary sound sources 5, 21.
  • the i-th entry of the vector a TM (t) is the fast determined for the primary sound source 3 that has been assigned to the secondary sound source 5, 21, whose fast forms the ith entry in the vector a TM (t).
  • the proportion p ps (c) of the sound pressure p TM (fc) measured at the respective sound pressure sensors 11 is determined, which is generated there by the primary sound sources 3.
  • the proportion H TM (k) af (k) of the secondary sound sources 5, 21 is subtracted from the determined secondary sound pressure p (fc) according to equation (5).

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  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Acoustics & Sound (AREA)
  • Multimedia (AREA)
  • Soundproofing, Sound Blocking, And Sound Damping (AREA)

Abstract

Il est décrit et revendiqué un procédé de suppression active d'un son d'une pluralité de sources sonores primaires au moyen d'un son d'une pluralité de sources sonores secondaires, une grandeur de réglage destinée à commander la source sonore secondaire de façon itérative étant déterminée par détermination de la célérité de chaque source sonore primaire, détermination de la célérité et de la pression acoustique de chaque source sonore secondaire, détermination de la célérité à supprimer efficacement pour chaque source sonore secondaire, la célérité à supprimer efficacement d'une source sonore secondaire en plus de la célérité, qui a été déterminée pour la source sonore primaire associée à la source sonore secondaire concernée, comportant également les célérités et les pressions acoustiques déterminées pour les autres sources sonores secondaires, détermination de la grandeur de réglage pour chaque source sonore secondaire de façon à déterminer et minimiser la différence entre la célérité à supprimer efficacement déterminée pour une source sonore secondaire et la célérité déterminée pour l'une des sources sonores secondaires et les sources sonores secondaires sont commandées avec les grandeurs de réglage respectives. En outre, il est décrit et revendiqué un système de suppression active de son par le procédé de l'invention.
PCT/EP2015/077787 2014-11-28 2015-11-26 Procédé et système de suppression active de son WO2016083513A1 (fr)

Applications Claiming Priority (2)

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EP14195457.8 2014-11-28
EP14195457.8A EP3026664B1 (fr) 2014-11-28 2014-11-28 Procédé et système d'atténuation phonique active

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2020024334A1 (fr) * 2018-08-01 2020-02-06 中科振声（苏州）电子科技有限公司 Système de réponse au bruit de vibration intelligent et procédé de réponse au bruit de vibration intelligent

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN108428444B (zh) * 2018-03-07 2021-06-22 南京大学 一种补偿次级声源近场影响的紧凑有源吸声方法

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20090180627A1 (en) * 2007-12-21 2009-07-16 Airbus Deutschland Gmbh Active sound blocker
EP2378513A1 (fr) * 2010-04-08 2011-10-19 Helmut-Schmidt-Universität Procédé et système de réduction de bruit active

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20090180627A1 (en) * 2007-12-21 2009-07-16 Airbus Deutschland Gmbh Active sound blocker
EP2378513A1 (fr) * 2010-04-08 2011-10-19 Helmut-Schmidt-Universität Procédé et système de réduction de bruit active

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
NICK STEFANAKIS ET AL: "Power-output regularization in global sound equalization", THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA, vol. 123, no. 1, 1 January 2008 (2008-01-01), pages 33, XP055189001, ISSN: 0001-4966, DOI: 10.1121/1.2816580 *

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2020024334A1 (fr) * 2018-08-01 2020-02-06 中科振声（苏州）电子科技有限公司 Système de réponse au bruit de vibration intelligent et procédé de réponse au bruit de vibration intelligent

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