Arrangement of speaker transducers and method of operating an arrangement of speaker transducers

Abstract

The invention relates to an acoustic transducer arrangement (1) based on the principle of wave field synthesis, characterized in that at least one first acoustic transducer (11) is coupled to an acoustic low pass filter unit (5). The invention relates to a method for operating a two-dimensional acoustic transducer arrangement.

Description

[0001] The invention relates to a sound transducer arrangement with the features of claim 1 and a method for operating a sound transducer arrangement with the features of claim 14.

[0002] The principle of wave field synthesis is well-known for the reproduction of audio signals (see, for example, Berkhout, AJ (1988): A holography approach to acoustic control. Journal of the Audio Engineering Society, Vol. 36, No. 12, December 1988, pp. 977–995). According to the Huygens principle, sound wavefronts are reconstructed from a multitude of elementary waves. Each elementary wave originates from the acoustic center of a transducer, which is driven by its associated amplifier. The superposition of elementary waves is also the basis of beamforming principles, which allow sound waves to be preferentially radiated in a desired direction (see, for example, Schröder, Jaeckel, Evaluation of beamforming systems, 4th Berlin Beamforming Conference 2012). In principle, these elementary waves are intended to synthesize the wavefronts across the entire audible frequency range.In order for the sound wavefronts synthesized from the elementary waves to be radiated with the same amplitude in every direction, the operating principle requires omnidirectional half-space radiation from the individual transducers. To prevent unwanted interference in the playback range, which manifests as aliasing effects, the individual transducers should theoretically be positioned at a distance of less than half a wavelength of the radiated signal from each other – even for the upper transmission range (e.g., above 4 kHz).

[0003] For the playback area, i.e., an interior and / or exterior space, wave field synthesis requires a source-free volume, meaning all reflections should be avoided. However, since complete acoustic isolation of the playback space is practically impossible, the wavefronts must be aligned in both the azimuth and elevation planes. This largely prevents the generation of reflections by ensuring that the reflective surfaces of the playback space are not unintentionally struck by the synthesized wavefronts.

[0004] With horizontal sound transducer rows around the audience, as implemented, for example, in a system at the TU Berlin ( http: / / www.fouraudio.com / de / referenzen / wellenfeldsynthese-an-der-tu-berlin.html That is not possible. Directed cylindrical waves are formed in the elevation plane.

[0005] From WO 2015 / 036845 A1, it is known to construct larger, two-dimensional transducer surfaces in modules according to the principle of wave field synthesis. However, with a two-dimensional transducer arrangement (e.g., DE 2005 10001395 A2) based on the principle of wave field synthesis, the requirement for aliasing-free reproduction across the entire transmission range leads to a disproportionately high level of complexity, because the total number of transducers quadruples when their spacing is halved. In practice, such radiating surfaces are therefore constructed in such a way that a largely closed wavefront can be generated up to the Forman region of speech reproduction, i.e., up to approximately 4 kHz. The audio frequencies above this are of less importance for the localization of the sound source, so direction-dependent aliasing effects are permitted here.

[0006] Dynamic loudspeakers are typically used as sound transducers in these applications. However, their resonant frequencies, given a given diaphragm diameter, lie several octaves above the lower cutoff frequency of the audio range to be reproduced, which is required for high-quality sound reproduction. Furthermore, the sensitivity and power handling of dynamic loudspeakers are far below the values ​​that are standard for larger loudspeakers.

[0007] In such a two-dimensional arrangement, the efficiency of the individual transducers improves with increasing signal wavelength because they operate more synchronously as the frequency decreases. Consequently, the air in front of the diaphragm can no longer move freely in all directions, resulting in a larger air mass in front of the diaphragm. Compared to a single transducer, the weight of the air column now being moved significantly improves the match to the air's radiation resistance, because the diaphragm no longer operates almost without resistance but encounters a working resistance. This leads to a significant increase in level towards lower frequencies. However, this increase cannot compensate for the steeper sound pressure drop of the driver below its resonant frequency. Therefore, using multiple transducers with a corresponding distribution of the radiated frequency ranges is an advantageous solution.

[0008] Such a division of the reproduction range into individual frequency bands leads to only minor irregularities in the vertical directivity of the system in horizontal WFS loudspeaker arrays, such as those in the lecture hall at TU Berlin (see Anselm Goertz, Michael Makatsch, Christoph Moldrzyk, Stefan Weinzierl: Equalization of loudspeaker signals for wave field synthesis systems, 25th TONMEISTERTAGUNG - VDT INTERNATIONAL CONVENTION, November 2008). Complex challenges arise in a planar or spatial loudspeaker arrangement based on the principle of wave field synthesis. Mounting the various loudspeakers in a single plane is not possible because the wavefront must be reconstructed in all three spatial dimensions without significant gaps in the spacing of the high-frequency loudspeakers.Therefore, the acoustic centers of the elementary waves, from which the wavefront to be synthesized is composed, do not lie in a common plane.

[0009] US 2012 / 207332 A1 shows an array of MEMS transducers.

[0010] Fig. 1 Figure 1 schematically depicts a cross-sectional view of a transducer arrangement. Three primary transducers 11 are shown, which are exemplary cone transducers in this example. A plurality of secondary transducers 12 are arranged between the primary transducers 11. In the illustrated embodiment, these are dome transducers, which are often used for the high-frequency range. The secondary transducers 12 can also be arranged in the region of the diaphragm of the primary transducers 11, as is known from coaxial loudspeakers, provided they do not obstruct the sound output. The arrangement of several high-frequency loudspeakers in front of the diaphragm of low-frequency loudspeakers is generally known.

[0011] Elementary waves 311, 312 each emanate from the first sound transducers 11 and the second sound transducers 12, having their point of origin in the acoustic centers 211, 212 of the first sound transducers 11 and second sound transducers 12.

[0012] In dome-shaped transducers, such as the second transducer 12 shown here, the acoustic centers 212 are located approximately on the front of the dome. In cone-shaped transducers, such as the first transducer 11 shown here, the acoustic centers 211 of the elementary waves 311 are located in the rear part of the cone, slightly in front of the dust cap (Sven Franz, Christina Imbery, Menno Müller, Jörg Bitzer: "Determination of the frequency-dependent acoustic center of a loudspeaker in the time domain"; Institute for Hearing Technology and Audiology Oldenburg). The exact position is frequency-dependent. Regarding the superposition of the elementary waves of the first and second transducers 11, 12, the position of the acoustic centers in the transition region of their operating frequencies is crucial.

[0013] As from Fig. 1 As can be seen, the arrangement and construction of the first and second sound transducers 11, 12 result in a geometric offset of their respective acoustic centers. In particular, the acoustic centers of the first and second sound transducers 11, 12 are not located on the same plane. With respect to the main propagation direction of the respective sound transducers 11, 12, the first sound transducer 11 is located behind the second sound transducer 12.

[0014] This geometric offset cannot be easily compensated for in time during wave field synthesis, and it also leads to problems with the superposition of elementary waves in beamforming methods. In the representation of the Fig. 1 It becomes clear that the elementary waves 311 of the rearward-shifted first cone transducers 11 can indeed be temporally aligned so that a common front line 4 forms with the elementary waves 312 of the second dome transducers 12. However, the radius of the elementary waves 311 of the cone transducers 311 is then larger than the radius of the elementary waves 312 of the dome transducers 12. This results in an inhomogeneous distribution of the wavefronts.

[0015] The superposition of inhomogeneous wavefronts, especially in the crossover region, inevitably leads to direction-dependent irregularities in the frequency response and to undesirable side loops. Such side loops should be avoided as much as possible if the aim is to forgo addressing the room acoustics. They could generate unwanted reflections that would counteract the source-free nature of the room acoustics inherent in wave field synthesis. Particularly in the midrange, where the crossover frequency is typically located, such reflections are easily localized, and therefore would significantly distort the spatial reproduction.

[0016] The task is to improve the radiation characteristics of a transducer arrangement, in particular to compensate for a geometric offset of transducers in a transducer arrangement.

[0017] This problem is solved by an object having the features of claim 1.

[0018] In this arrangement, at least one first sound transducer is coupled with an acoustic low-pass filter device.

[0019] For example, the acoustic center of the first transducer can be located behind the acoustic centers of the high-frequency transducers in relation to the front of the transducer arrangement.

[0020] The acoustic center of the first transducer and the low-pass filter device can, for example, in one embodiment, be shifted into a plane with the acoustic centers of high-frequency transducers as the second transducer. This makes it possible to ensure a homogeneous superposition of elementary waves even in the crossover frequency range, although the drivers of the transducers themselves are mounted in different planes. In such a "loudspeaker system," the sound waves no longer originate from the loudspeaker itself. It only builds up air pressure in the chamber, not a wave. The sound wave arises at the outlet of the air duct from the vibrating column of air.

[0021] An acoustic low-pass filter utilizes the spring effect of an air volume in series with the mass of the air (1.293 g / L) in a channel. The volume can then be considered to be the chamber volume plus the volume of the diaphragm cone. Air can only exit the channel, so the acoustic center is located at the outlet of this channel. The acoustic low-pass filter results, among other things, in a 90-degree phase shift at the outlet of the air channel, which is taken into account when driving tweeters.

[0022] The at least one acoustic low-pass filter device can be positioned upstream, i.e., in particular in the main propagation direction of the elementary wave generated by the at least one first transducer. However, the filter device can also assume other positions relative to the coupled transducer, e.g., offset or positioned laterally. In one embodiment, however, the outlet of the air duct with its oscillating air mass, which, together with a loudspeaker chassis and the acoustic low-pass filter, is the acoustic center and origin of the elementary wave of the at least one first transducer, can terminate in the plane of the acoustic centers of the transducers.

[0023] The acoustic low-pass filter device can be, or include, a mechanical device. As such, it can have a resilient air volume in an air chamber. The air chamber can be located in front of the coupled transducer.

[0024] A cavity, in particular the volume of the diaphragm cone, of the coupled transducer can also be part of the air chamber of the acoustic low-pass filter device, and / or a part of the transducer can be part of the boundary of the air chamber. Specifically, a cone of the transducer can be part of the air chamber or constitute the entire air chamber. The cone can also be in air-conducting communication with another air chamber of the acoustic low-pass filter device. A cone volume of the at least one first transducer can be part of or equal to the volume of the resonating air. The acoustic low-pass filter device can have a throat or a comparable constriction of the air outlet that encompasses a vibrating air mass.

[0025] The neck of the acoustic low-pass filter device need not be a tube. Rather, it can deviate from a straight line and have an approximately circular or polygonal cross-section, or any other shape. A straight tube can also have a cross-section that deviates from a circular one.

[0026] The opening of the neck to the environment can be integrated into a plate in front of the respective at least one first sound transducer; an opening in such a plate can also be designed as an opening of the neck to the environment or as the neck itself.

[0027] It should be noted that a portion of the upstream air is relatively rigidly connected to the air in the duct and must therefore be included in the vibrating mass. The corresponding calculation principles for this are known from the port correction of bass reflex tubes.

[0028] The first transducer, at least one, is designed as a midrange transducer, a mid-bass transducer, and / or a bass transducer. It can be a dynamic loudspeaker, in particular a cone transducer, but can also be implemented using a different transducer principle.

[0029] In one embodiment, a plurality of first sound transducers are arranged in a pattern. This pattern can, in particular, be a one-, two-, or three-dimensional grid pattern in which the first sound transducers are arranged regularly or almost regularly (e.g., a slight offset due to aliasing is possible). For example, sound transducers of a similar design or with a similar frequency range (e.g., midrange, mid-bass, or bass transducers) can occupy analogous positions.

[0030] Further transducers in the transducer array are arranged relative to each other in a second pattern, in particular a grid pattern. These additional transducers are high-frequency transducers, especially dome tweeters.

[0031] The first and second patterns can superimpose to form a single pattern or represent a superposition of two grid patterns. In one embodiment, the second transducer can also be mounted within the vibrating air mass, in which case its influence on the cutoff frequency of the acoustic low-pass filter must be considered.

[0032] The at least one acoustic low-pass filter device is a Helmholtz type.

[0033] The device is designed as a resonator or incorporates a Helmholtz resonator. A Helmholtz resonator consists of an air volume of arbitrary shape, connected to the surroundings via a relatively small-volume neck. The air in the neck can be considered an inertial mass. The entire air volume forms an elastic volume, resulting in a spring-mass system. Such a spring-mass system can, for example, be coupled to a transducer by being positioned in front of it. In this way, the Helmholtz resonator serves as a low-pass filter device.

[0034] In a further embodiment, the acoustic low-pass device can be designed such that the numerical value of the ratio of the area of ​​the outlet opening to the product of the volume of its air chamber and the length of its neck S V ⋅ L between 100 and 5000, where the area and volume are given in square meters and cubic meters respectively, and the length of the neck in meters.

[0035] The acoustic centers of the first sound transducers with coupled low-pass filter devices lie in one plane.

[0036] Furthermore, the acoustic center of at least one first transducer with coupled low-pass filter device and the acoustic center of a second transducer of the transducer arrangement lie in one plane.

[0037] The area can be defined, in particular, by the acoustic centers of the first and second transducers – using the low-pass filter device. Accordingly, the acoustic centers of the first transducers and the associated acoustic low-pass filter devices, as well as the acoustic centers of the second transducers in the transducer arrangement, can be arranged in a surface, especially a plane.

[0038] The acoustic center of the at least one first transducer can be positioned by means of the coupled acoustic low-pass filter device, in particular shifted along the direction of sound propagation. This can be used to adjust the spatial radiation characteristics of the transducer arrangement, especially for a homogeneous structure of the elementary waves of wave field synthesis or a related beamforming method.

[0039] The direction of displacement of the first acoustic center of the at least one first sound transducer can be collinear with the direction of propagation of an elementary wave generated by the at least one first sound transducer. The direction of propagation of the elementary wave is determined by the vector that is perpendicular to the plane that bounds the half-space into which the sound transducer radiates.

[0040] In particular, the acoustic center of the at least one first sound transducer can be shifted by means of the coupled acoustic low-pass filter device such that it lies on the plane of a second sound transducer, wherein the plane of the height of the acoustic center of a second sound transducer is described by the plane that passes through the acoustic center of the sound transducer and is perpendicular to the vector of the propagation direction of the elementary waves generated by the sound transducer.

[0041] Conversely, the acoustic center of the first transducer can also be shifted by means of the coupled acoustic low-pass filter device so that the acoustic center of a second transducer lies on the plane of the height of the shifted acoustic center.

[0042] In a further embodiment, the additional phase shift of a signal from the at least one first transducer, which arises from coupling with an acoustic low-pass filter device, can be compensated for by adjusting the control, in particular by delaying the control of the at least one second transducer, so that the elementary waves of the transducers in the transducer arrangement superimpose to form a common wavefront.

[0043] In one embodiment, the cutoff frequency of the at least one acoustic low-pass filter device can be tuned above, in particular one to two octaves above, a crossover frequency of a transmission range of the respective at least one first transducer. Accordingly, the transmission range of the at least one first transducer does not need to be significantly altered by coupling with one of the acoustic low-pass filter devices.

[0044] Furthermore, second transducers, particularly for the high-frequency range, can be oriented differently from the main axis of the transducer array, which is perpendicular to the two-dimensional transducer surface. This aims to linearize the sound reproduction for distant listeners located far from the main axis in the transducer array's radiation direction. The main axis of the transducer array can refer to a local area in the case of curved surfaces.

[0045] The described embodiments also relate to a modular transducer system, which, for example, comprises at least two transducer assemblies arranged such that the radiating surfaces of the respective transducer assemblies are arranged in a plane, are part of a curved surface, or approximate a curved surface. The described embodiments relate to a module within the modular transducer system or to the modular transducer system as a whole.

[0046] A module in a transducer system can be designed, or include, a three-way module. This module can comprise first transducers, designed as cone transducers and suitable for transmitting the mid-frequency spectrum. These are each coupled to an acoustic low-pass filter device.

[0047] Furthermore, the module can incorporate dome tweeters suitable for audio transmission of the upper frequency spectrum. These can be mounted in groups on circuit boards such that their spacing is smaller than that of the midrange drivers. Specifically, their spacing should be smaller than the shortest wavelength of the frequency range to be transmitted without perceptible aliasing. At the upper limit of the transmission range, wavelengths of approximately 2.15 cm result. In practice, a spacing of 4–12 cm, and especially 8 cm, between tweeters is usually sufficient to ensure transmission without perceptible aliasing.

[0048] Furthermore, the module can have at least one bass transducer located behind the high-frequency and mid-frequency transducers, and the sound pressure generated by which can be implemented as a double-vented bandpass enclosure.

[0049] The following explains the relationships and embodiments with reference to the drawings. These show: Fig. 1 a sectional view of a sound transducer arrangement according to the state of the art; Fig. 2 a schematic sectional view of a sound transducer arrangement in which the first sound transducers are each coupled to an acoustic low-pass filter device; Fig. 3 a sectional view of a sound transducer arrangement in which the first sound transducer is coupled with an acoustic low-pass filter device and the generated elementary waves of the first and second sound transducers superimpose to form a common, homogeneous wavefront; Fig. 4 a first sound transducer of a sound transducer arrangement, which is coupled to an acoustic low-pass filter device; Fig. 5 schematically a grid pattern in which the first and second sound transducers of a sound transducer arrangement are arranged relative to each other; Fig. 6 a sectional view of a transducer arrangement in which the first transducer is coupled with an acoustic low-pass filter device, resulting in a homogeneous wavefront. Fig. 7 a sectional view of a transducer arrangement in which the first transducers are coupled with an acoustic low-pass filter device and with second transducers with adapted orientation; Fig. 8 a perspective view of an exemplary embodiment of a sound transducer module; Fig. 9 a perspective view of an embodiment of a modular sound transducer system; Fig. 10 another embodiment of a sound transducer arrangement.

[0050] Fig. 2 schematically shows a sectional view of a sound transducer arrangement 1 or a sound transducer module 7 (as exemplified in Figur 8 (as shown). This, and all subsequent embodiments, show embodiments for transducer arrangements and methods for operating transducer arrangements.

[0051] The illustration shows first sound transducers 11, each coupled to an acoustic low-pass filter device 5. The section shows four first sound transducers 11, but this number is only for illustrative purposes.

[0052] The acoustic low-pass filter device 5 is shown here directly in front of the first sound transducers 11, i.e. in particular in the positive propagation direction 3111 of the elementary wave 311 generated by the respective first sound transducers 11.

[0053] This positioning is only an example; other positioning options, e.g. offset or lateral positioning of the acoustic low-pass filter device 5 with reference to the coupled first transducer 11, are also possible.

[0054] The in Fig. 2 The first sound transducers 11 shown are arranged equidistantly on a straight line. In further embodiments, first sound transducers 11 of a region of a sound transducer arrangement 1, a sound transducer module 7, or even the entire sound transducer arrangement 1, are arranged relative to each other in a first pattern 611, in particular a grid pattern. This pattern can be one-, two-, or three-dimensional, in particular also such a grid pattern (see e.g. Fig. 5 ).

[0055] Furthermore, it shows Fig. 2 Second sound transducers 12, whose positions alternate with those of the first sound transducers 11 along the straight line. This particular arrangement is also only shown as an example. The second sound transducers 12 could be arranged in a second pattern 612, in particular a grid pattern. Further sound transducers of the partially illustrated transducer arrangement could also be arranged in a second pattern. In one embodiment, the first pattern 611 and the second pattern 612 can be superimposed to form a common pattern 6, as shown by way of example in Fig. 5 is shown.

[0056] The second sound transducers 12 referred to below can be the second sound transducers 12 of the sectional view shown, but also second sound transducers 12 at a different position of the Fig. 2 The sound transducer arrangement 1 is shown in part. In particular, the second sound transducers 12 do not need to be in immediate spatial proximity to the first sound transducers 11 in the sound transducer arrangement.

[0057] The elementary waves 311 generated by the first sound transducers 11 have their apparent origin in an acoustic center 211, which is located in Fig. 2 The acoustic center 211 of a first sound transducer 11 can, for example, be determined by the design of the first sound transducer 11. For instance, the acoustic center of a cone sound transducer is located in the rear part of the cone, approximately at the front of the dust cap.

[0058] The acoustic centers 211 of the first sound transducers 11 can be positioned by means of the coupled acoustic low-pass filter device 5, in particular along an axis. This is demonstrated with reference to Fig. 3 and 4The location of the displaced acoustic center 211 can be regulated and determined, for example, by the type or design of the acoustic low-pass filter device 5 and / or by the placement of the acoustic low-pass filter device 5 in relation to the coupled first sound transducer 11.

[0059] In particular, the acoustic center 211 of a first sound transducer 11 can be shifted collinearly to the propagation direction 3111 of the elementary wave 311 generated by the first sound transducer 11 by means of the coupled acoustic low-pass filter device 5.

[0060] By coupling with the acoustic low-pass filter device 5, the acoustic center 211 of the first sound transducers 11 can be positioned so that the radii of curvature of the elementary waves 312, 311 generated by coupled first sound transducers 11 and by second sound transducers 12 are adapted or correspond, thus enabling the generation of a homogeneous wavefront 4 by the sound transducer arrangement 1 or the sound transducer module 7.

[0061] For example, the acoustic centers 212 of second sound transducers 12 and the acoustic centers 211 of first sound transducers 11 with coupled acoustic low-pass filter device 5 can be positioned on a common surface, in particular on a convex or concave plane.

[0062] The acoustic center 211 of a first sound transducer 11 can be shifted by means of the coupled acoustic low-pass filter device 5 such that the shifted acoustic center 211 lies on the plane of the height of the acoustic center 212 of a second sound transducer 12, wherein the plane of the height of the acoustic center of a sound transducer is described by the plane that passes through the acoustic center of the sound transducer and is perpendicular to the vector of the propagation direction of the elementary waves generated by the sound transducer.

[0063] The cutoff frequency of an acoustic low-pass filter device 5 determines the frequency range that is attenuated by the filter device; specifically, sound above the cutoff frequency is attenuated and sound below the cutoff frequency is allowed to pass through almost unhindered.

[0064] In one embodiment, the cutoff frequency of the acoustic low-pass filter device 5 is tuned above the operating range or above, in particular one to two octaves above, the crossover frequency of a transmission range of the first transducer 11 coupled to the acoustic low-pass filter device 5.

[0065] The cutoff frequency can be adjusted in particular so that the playback frequency range of the first transducer 11 is not significantly changed by coupling with an acoustic low-pass filter device 5, in particular the acoustic low-pass filter device 5 has no undesirable audible effect on the transmission range of the coupled first transducer 11.

[0066] If the cutoff frequency of the acoustic low-pass filter 5 is close to the upper limit of the transmission range of the respective first transducer 11 for the lower transmission range, harmonics of the first transducer 11 cannot reach the listeners, which can reduce the distortion factor of the first transducer 11.

[0067] The first 11 transducers can be, for example, midrange transducers, mid-bass transducers, and / or bass transducers. These can be implemented, for example, as dynamic loudspeakers, especially as cone transducers, as in Fig. 3 and 4 The second transducer 12 can be high-frequency transducers, which are implemented as dome transducers ( Fig. 3 The acoustic low-pass filter devices 5 may in particular include resonators (i.e., an air system consisting of a mass and a resilient air volume), as described in the Figuren 3 and4 is shown.

[0068] Fig. 3 Figure 1 shows a sectional view of a sound transducer arrangement 1 or a sound transducer module 7, which is a special embodiment of the subject matter of the Fig. 2 to be understood. In particular, descriptions of the Fig. 2 also on Fig. 3 transmitted. Fig. 3 is also applied as an embodiment to the subject matter of Fig. 1 to understand.

[0069] The first 11 loudspeakers are in Fig. 3 Shown as an example of a cone loudspeaker, which is typically used for the midrange to bass frequency range.

[0070] Each of the first sound transducers 11 is coupled to an acoustic low-pass filter device 5. This is in Fig. 3 each placed directly in front of the first sound transducers 11 and as a mechanical device which, with reference to Fig. 4 It is described in more detail and illustrated.

[0071] The illustrated mechanical acoustic low-pass filter devices 5 each have a resilient air volume 53 in an air chamber 51. In the Fig. 3 In the exemplary embodiment shown, the air chamber 51 consists of the cone 511 of the cone transducer 11 and a further air chamber 512. Therefore, the resilient air volume 53 consists of the cone volume 531 and, optionally, a further air volume 532. However, the air chamber 51 could also correspond to the cone 511 or comprise or contain another air chamber of the first transducer 11. A part, in particular a wall, of the first transducer 11 could form part of the boundary of the air chamber 51. The air chamber 51 could also be constructed independently of the first transducer 11; in particular, the air chamber 51 could have no common boundaries with the first transducer 11.

[0072] In the Fig. 3 In the illustrated embodiment, the air chambers 51 of the acoustic low-pass filter devices 5 are partially limited by a plate 55 which is placed in front of the first sound transducers 11.

[0073] The in Fig. 3 The illustrated embodiment of the acoustic low-pass filter device further comprises a neck 52 which includes a vibrating air volume 54.

[0074] In Fig. 3 The necks 52 of the three acoustic low-pass filter devices 5 are aligned such that their openings 521 to the surroundings lie in one plane. In the illustrated form, openings 551 in the plate 55, which partially confines the air chambers 51, form part of the confinement of the necks 52. This design is merely an example.

[0075] By coupling with the acoustic low-pass filter devices 5, the acoustic center of the first sound transducers 11 is shifted approximately to the height of the openings of the necks 52. A comparison of the acoustic centers 211 of the first sound transducers 11 in Fig. 1 with the acoustic centers 211 of the first sound transducers 11 with the coupled acoustic low-pass filter device 5 in Fig. 3 This shows that the acoustic centers of the first sound transducers 11 were shifted by coupling with the acoustic low-pass filter devices 5. In particular, the acoustic centers were shifted along the propagation directions of the elementary waves 311 generated by the respective first sound transducers 11. The shifted acoustic centers 211 of the first sound transducers 11 lie on a surface.

[0076] Fig. 3 Figure 12 further shows a second sound transducer 12, which is shown as an example of dome transducers typically used for the high-frequency range. The dome transducers are shown here as an example mounted on the plate 55, which forms the boundary of the air chambers 51 of the acoustic low-pass filter device 5. The plate can also serve as the mounting board for the second sound transducer.

[0077] The first sound transducers 11 and the second sound transducer 12 are arranged in a common grid pattern 6, in particular following the in Fig. 3 The arrangement shown consists of a first sound transducer 11 and three second sound transducers 12 in a repeating manner. This arrangement is merely an example. The second sound transducers 12 can also be mounted in the area of ​​the air duct opening, provided their influence on the vibrating air mass is taken into account when dimensioning the acoustic low-pass filter.

[0078] In the Fig. 3 In the illustrated embodiment, the openings 521 of the necks 52 of the acoustic low-pass filter devices 5 and the domes 721 of the dome transducers lie approximately on the same surface. Since the displaced acoustic centers (displaced by the acoustic low-pass filter devices 5) lie approximately at the height of the opening of the necks 52 and the acoustic centers 212 of the dome transducers lie on their domes 721, the acoustic centers 211 of the first transducer 11 with coupled low-pass filter devices 5 and the acoustic centers 212 of the second transducer 12 lie approximately on the same surface.

[0079] In particular, by coupling with the acoustic low-pass filter devices 5, the acoustic centers 211 of the first sound transducers 11 were shifted to the plane in which the second sound transducers 12 have their acoustic centers 212.

[0080] The radii of curvature of the elementary waves 311, 312 of the first sound transducer 11 and the second sound transducer 12 are aligned by shifting the acoustic centers relative to each other, which is shown by a comparison with the radii of curvature of the elementary waves 311, 312 in Fig. 1 shows.

[0081] Within the framework of coupling with an acoustic low-pass filter device 5, a phase shift of the signals from the first transducers 11 is induced. This additional phase shift of the signal from the first transducers 11 can be compensated for by an adapted control of second transducers 12, in particular by a delay in the control of the second transducers 12, so that the elementary waves 311, 312 superimpose to form a common, homogeneous synthesized wavefront 4. This is demonstrated by a comparison of the wavefront in Fig. 3 with the wavefront in Fig. 1 clarifies.

[0082] Fig. 4 Figure 1 shows a single first transducer 11 from a transducer arrangement 1, which is coupled to an acoustic low-pass filter device 5. The first transducer 11 is shown here as an example of a cone transducer.

[0083] An acoustic low-pass filter device 5 is coupled to the first sound transducer 11. This is shown here in the mechanical embodiment of an acoustic low-pass filter device, which is placed directly in front of the first sound transducer 11.

[0084] In the acoustic low-pass filter device 5, a resilient air volume 53 is coupled to a vibrating air volume 54; the former corresponds to a spring. The resilient air volume 53 and the vibrating air volume 54 form a mass-spring system. The resilient air volume 53 is enclosed by an air chamber 51, and the vibrating air volume 54 is enclosed by a short neck 52. This corresponds to a Helmholtz resonator.

[0085] In Fig. 4 The air chamber 51, which comprises the resilient air volume 53, consists of the cone 511 of the cone sound transducer 11 and a further air chamber 512. Thus, the resilient air volume 53 consists of the cone volume 531 and a further air volume 532.

[0086] Part of the boundary of the neck 52 of the in Fig. 4 The acoustic low-pass filter device 5 shown has an opening 551 in a plate 55 in front of the first sound transducer 11; that is, the opening 551 in the plate 55 is integrated into the throat 52. The opening 551 in the plate 55 could also correspond to the opening 521 of the throat 52 to the surroundings. Alternatively, the opening in the plate 551 could correspond entirely to the throat 52. The throat 52 could also have been formed in a different way.

[0087] If several, e.g. all midrange transducers, all mid-bass transducers and / or all low-frequency transducers, are coupled in a transducer arrangement 1 with an acoustic low-pass filter device 5, a plate 55 in front of the transducer arrangement 1 can have several openings 551, each of which serves as openings 521 of the necks 52 of the various acoustic low-pass filter devices 5 or is integrated into the necks 52 of the acoustic low-pass filter devices 5.

[0088] In the illustrated embodiment, the neck 52 is designed as a tube, in particular having a circular cross-section. However, it could also have a different cross-section, e.g., a polygonal one. The opening of the neck can also have a different shape, which may be determined in particular by the overall design of the transducer arrangement or result from its design.

[0089] The acoustic center of the first sound transducer 11 migrates by coupling with the acoustic low-pass filter device 5 to the end of the neck 52 of the acoustic low-pass filter device 5, in which the oscillating air volume 54 determines the upper cutoff frequency of the acoustic low-pass filter device 5.

[0090] In the Fig. 4 In the example shown, the acoustic center of the first sound transducer 11 is shifted in the direction of propagation 3111 or by the elementary wave 311 generated by the first sound transducer 11 by means of the coupled acoustic low-pass filter device 5.

[0091] The cutoff frequency of the acoustic low-pass filter can be calculated analogously to the calculation of the resonant frequency of a Helmholtz resonator. The cutoff frequency of the acoustic low-pass filter should be at least one third to one octave higher than the electrical crossover frequency of an electronic crossover network in the corresponding loudspeaker.

[0092] The resonant frequency is calculated using the following formula. f = c 2 π S V ⋅ L , where c is the speed of sound, S the cross-section of the opening of the neck, L the length of the neck and V This is represented by the volume of the spring-like air mass. Additionally, the muzzle opening correction must be taken into account, because a portion of the upstream air must be included in the oscillating mass.

[0093] The cutoff frequency of this acoustic low-pass filter device can be calculated analogously to the calculation of the resonant frequency of a Helmholtz resonator. This is calculated using the formula... f = c 2 π S V ⋅ L , where c the speed of sound in m / s, S the area of ​​the neck's exit opening in m² < , L the length of the neck in m and V Represent the volume of the springing air mass in m³.

[0094] Additionally, the muzzle opening correction must be taken into account, because a portion of the upstream air must be included in the oscillating mass. The formula then changes to f = c 2 π S V ⋅ L + 2 d This is because the twice-diameter of the neck opening, multiplied by the length of the neck, is added to the amount of air moving. This results in slightly lower values ​​for the cutoff frequency.

[0095] The upper end of the operating range of a midrange transducer typically lies between 1 and 4 kHz. With the cutoff frequency of the coupled acoustic low-pass filter above the midrange driver's transmission range, the resulting ratio is, for example, the area of ​​the exit opening to the product of the volume and length of the neck. S V ⋅ L between 100 and 5000.

[0096] Fig. 5 Figure 6 schematically shows a pattern 6 in which sound transducers of a sound transducer arrangement are arranged. A plurality of first sound transducers 11, arranged in a first grid pattern 611, and further sound transducers, arranged in a second grid pattern 612, are shown.

[0097] In the form shown, the first grid pattern 611 and the second grid pattern 612 overlap to form a common grid pattern 6.

[0098] The first 11 transducers can be, for example, midrange transducers, mid-bass transducers, and / or bass transducers. These could, for example, have been implemented as cone transducers. The first prototype can be, as in Fig. 5 The pattern shown is a grid pattern, but other regular arrangements of the transducers are also possible. The pattern can also be one-, two-, or three-dimensional. For clarity, the low-pass filter devices 5, which are coupled to the first transducers 11, are shown here only with their openings. A second transducer 12 can also be mounted within the opening if its influence is included in the low-pass calculation.

[0099] In the first pattern 611, for example, sound transducers of a similar design type or a similar operating range can occupy analogous positions.

[0100] The additional transducers can be, for example, tweeters, woofers, and / or midrange drivers. For instance, some of these additional transducers may be dome tweeters.

[0101] In the second pattern 612, additional transducers of a similar design or operating range can occupy similar or repeating positions. However, their positions can also deviate from the regular grid if the propagation delays and levels for their control are interpolated accordingly to the coordinates of the regular grid. As described in DE 10 2009 006 762 A2, aliasing effects in the upper playback frequency range can be reduced in this way.

[0102] The first and second patterns can represent a superposition of two grid patterns or combine to form a single grid pattern. Within this grid pattern, transducers of a similar type (e.g., cone or dome loudspeaker) or a similar designated frequency range (e.g., tweeter, midrange, and / or woofer) can occupy analogous positions.

[0103] The invention will be explained below using a further embodiment. Other embodiments, including those with a different frequency range distribution, are possible.

[0104] Fig. 6 shows similarity to the embodiment according to Fig. 3 A sectional view of a transducer arrangement 1 or a transducer module 7. The descriptions from Fig. 3 can be applied to the representation shown here.

[0105] Additionally, in Fig. 6 the directional characteristics 3121 of the second transducer, which are used here as in Fig. 3 The dome-shaped sound transducers are shown. The propagation directions of the elementary waves generated by the first and second sound transducers run parallel to each other.

[0106] High-frequency drivers can only radiate sound uniformly in all directions if their diaphragm diameter is smaller than the wavelength of the sound they are meant to produce. At 16 kHz, this is only 2.15 cm. However, with such a small diaphragm area, very little sound pressure can be generated at the lower end of their frequency range. A compromise must always be found between uniform spatial dispersion, maximum sound pressure, and the lower cutoff frequency of the transmission range. A low crossover frequency to the midrange drivers allows for a greater distance between the individual midrange drivers, because aliasing effects in the crossover region must be avoided. This greater distance then also allows for larger diaphragm diameters, which in turn enables more efficient reproduction at the lower end of the midrange drivers' frequency range.

[0107] The radiation pattern of high-frequency transducers is not constant in all directions; at certain frequencies, significant dips in radiation pattern are unavoidable and depend on the direction. This is in Fig. 6 This is illustrated by the irregular shape of the directional characteristics 3121. These problems increase with the diaphragm diameter due to the inherent nature of the design. For listeners located far from the transducer array, the solid angle of adjacent transducers is almost identical. This leads to a non-linearity in the frequency response at the relevant frequencies, which depends on the listener's position within the playback area.

[0108] This non-linearity cannot be compensated for by equalizing the overall signal, because this would result in an overemphasis of the frequency in question at other points. With reference to Fig. 7 It explains how the described effect can be reduced.

[0109] Fig. 7 shows a sectional view of a Fig. 6 of comparable structure. In contrast to the structure in Fig. 6 The mounting directions of the second sound transducer 12 have been changed.

[0110] In particular, the second transducers 12, which can be used for the high-frequency range in the exemplary setup, are oriented differently from the main axis 81 of the system. This is intended to linearize the reproduction for distant listeners who are located far away from the main axis in the radiation direction of the transducer arrangement 1.

[0111] In the exemplary embodiment shown, the high-frequency transducers 12 are not mounted parallel on a plate but slightly inclined, so that the inclination angles of the high-frequency transducers are slightly different and deviate in particular from the main axis 81 of the system.

[0112] This randomly distributed, slight deviation in the mounting direction of the 12 high-frequency transducers can affect the performance in relation to Fig. 6 reduce the described effect. Although, as in the Fig. 6 In the depicted scenario, the radiation pattern of the high-frequency transducers 12 is not constant in all directions, as represented by the irregular shape of the directional characteristics 3121. Therefore, from a given listening position, not all high-frequency loudspeakers are aligned in the same direction. This prevents an extensive area of ​​the transducer array from being mechanically positioned precisely in the direction towards the listener where the radiation of a specific frequency is significantly reduced.

[0113] Fig. 8 This figure exemplifies the construction of a transducer module, shown here as a three-way module, based on the principle of wave field synthesis. In this example, the upper frequency spectrum of the audio transmission range is realized using dome transducers 72. Cone transducers 71 are used for the mid-frequency spectrum, and the bass range is implemented as a double-vented bandpass enclosure 731, 732.

[0114] The in Fig. 8 The dome transducers shown have a very shallow overall depth. They are mounted in groups on circuit boards, which connect them to the amplifiers on the rear of the modules via connectors. Their spacing is chosen to ensure largely alias-free reproduction, even up to the Forman range of vowels. Within their operating range, they guarantee half-space radiation without significant dips in the directional characteristics. In principle, however, the solution according to the invention is not limited to the use of dynamic transducers.

[0115] At the upper frequency limit of their operating range, the diaphragm diameter of high-frequency transducers lies close to the radiated wavelength. Here, they are therefore relatively well matched to the operating resistance of the air, and the phase of the signal can differ significantly between adjacent transducers. Consequently, no improvement in efficiency due to improved matching compared to each individual transducer can be expected.

[0116] In contrast, the phase differences between adjacent transducers at the lower frequency limit of their operating range are small. The wavelength of the signal is several times larger than their diaphragm diameter. This is where the advantage of the group's better matching to the load impedance of the transmission medium, compared to a single transducer, comes into play. The efficiency increases significantly compared to that of an identical single radiator, and the weight of the air column now pressing on the dome shifts its resonant frequency considerably downwards. The otherwise necessary coupling of the transducer, approximately one octave above its resonant frequency, can be shifted downwards to the region near its free-air resonance.

[0117] The improved efficiency then contributes to the transducer arrangement being able to generate higher maximum sound pressure levels than is possible with conventional PA loudspeakers. Because of the distributed arrangement of the transducers, the problem arises that the air in front of the small diaphragm area of ​​a tweeter must be compressed into the non-linear range in order to generate the high sound pressure levels often typical at live events, even in a large audience area. This is what limits the theoretically possible maximum sound pressure level of conventional loudspeaker systems.

[0118] In front of the larger overall area of ​​the generating drivers in the planar transducer arrangement 1 according to the principle of wave field synthesis, the sound pressure in front of each individual transducer remains much lower, so that with appropriate design of the amplifiers and drivers in the audience area a significantly higher sound pressure can be generated without the non-linearity of the air compression curve leading to non-linearities in the perceived audio signal.

[0119] Furthermore, the improved efficiency of the planar transducer arrangement 1 significantly simplifies the selection of transducers for the adjacent frequency range. Their distance from each other should be less than the wavelength at the upper limit of their transmission range. This can also be practically achieved due to the relatively low coupling of the high-frequency transducers 72.

[0120] The diaphragm diameter of the cone loudspeakers used remains below the radiated wavelength across their entire frequency range. At the lower end of the band, the signal wavelength is more than an order of magnitude larger than any individual diaphragm, meaning it would be completely mismatched if it weren't working in conjunction with the neighboring transducers. In the bass range, this improved group matching therefore results in a very significant increase in efficiency, comparable to the improved driver matching in horn loudspeakers.

[0121] However, drivers with a diaphragm diameter resulting from their relatively small spacing are insufficient to generate the extreme sound pressure levels in the low bass range that are considered essential in modern PA applications. The resonant frequency of dynamic loudspeakers of a corresponding diameter is usually well above 100 Hz if they possess the high sensitivity required in PA systems. Below this resonant frequency, the sound pressure curve drops significantly more steeply than the increase due to the efficiency of the driver group can compensate for.

[0122] While external subwoofers could be added to the two-way modules as usual, integrating the sub-bass range into a wave field synthesis transducer surface offers significant advantages when a larger number of modules are combined to form a transducer surface. Besides better impedance matching, a sufficiently large surface area also allows for significant directivity extending into the deep bass range.

[0123] The wavelengths of the signal in the deep bass range are so large that the diaphragm excursions during wave field synthesis are largely synchronized, even across multiple modules. Despite their large diameter, each individual diaphragm is much smaller than the wavelength of the generated signal across its entire operating range. Therefore, the efficiency in the bass range also benefits from the arrangement of the individual transducers within the modular array of a two-dimensional radiator surface.

[0124] Therefore, the exemplary setup is designed as a three-way module 7. The volume required for the bass transducer 73 can only be positioned behind the transducers for the midrange and treble frequencies 71 and 72. This creates the problem that the generated sound pressure must find its way to the front of the planar transducer array 1. The continuity of the front-mounted radiating surface must be disturbed as little as possible, because this would cause diffraction effects with corresponding side lobes in the directional characteristic.

[0125] As in the Fig. 8 As can be seen, the exemplary solution is therefore implemented as a double-vented acoustic bandpass filter device 731, 732. The two forward-facing channels interrupt the structure of the high-frequency transducers 72 and mid-frequency transducers 71 only to a tolerable extent. The operating principle of the double-vented design, however, enables an efficiency with which the bass range does not drop off against the high sound pressure of the upstream transducer arrangement 1 for the mid- and high-frequency range. In principle, it would also be possible to arrange tweeters in the area of ​​the openings of the double-vented bandpass system if they are included in the system calculations. However, the air movement in the channels of the sketched example is so strong that audible turbulence noise would then be to be expected.

[0126] The high efficiency of the double-vented bandpass 731, 732 bass transducer is inherently linked to the limited bandwidth and a non-linearity of the phase response.

[0127] At emitted wavelengths of several meters, both openings in the front can be considered almost a single acoustic center. This allows for temporal correction without creating an inhomogeneous field in the transition region. However, temporal correction at these long wavelengths significantly increases the system's latency. This becomes a problem in any live performance. A balance must be struck between low system latency and a linear phase response. Compromises or different setups are possible.

[0128] The wavelengths of the signal in the deep bass range are so large that the diaphragm excursions during wave field synthesis are largely synchronized, even across multiple modules. Despite their large diameter, each individual diaphragm is much smaller than the wavelength of the generated signal across its entire operating range. Therefore, the efficiency in the bass range also benefits from the arrangement of the individual transducers within the modular array of a two-dimensional radiating surface.

[0129] Generally speaking, a sound transducer arrangement can be described as two-dimensional if the individual transducers are not arranged in a single (linear) line. In this case, for example, a slight offset of individual transducers perpendicular to the linear extent can usually be neglected.

[0130] When referring to a three-dimensional transducer arrangement, in addition to the planar arrangement, the arrangement of individual transducers perpendicular to the surface is also important. The entire surface can also be curved or bent.

[0131] In this sense, the embodiments described above can be, for example, in accordance with Fig. 8 These are referred to as three-dimensional transducer arrangements. In these designs, the relative distance between the individual transducers is quite important.

[0132] In Fig. 9 An example of a modular transducer system is shown, in which a variety of transducer arrangements – as described above – are used as modules. In principle, the transducer system can have more columns and / or more rows.

[0133] In the Fig. 10 An arrangement of several second sound transducers 12 is shown, which are also mounted in the air duct of the acoustic low-pass filter device of the first sound transducer 11. This divides the air duct with the vibrating air mass 54 into several sub-sections. The total air mass in the air duct remains unchanged. However, instead of a single acoustic center of the acoustic low-pass filter device, several air outlets 56 are created. According to Huygens' principle, each of these air outlets 56 forms the starting point of an elementary wave 57.

[0134] In the schematic representation, these elementary waves 57 each have the same radius, and therefore the same time delay, as the elementary wave emanating from the acoustic center of the first transducer 58. It becomes clearly visible that these elementary waves 57 diverge significantly from the elementary wave 59 of one of the second transducers 12 at the acoustic center of the first transducer 11 with increasing deviation from the center line. However, they remain symmetrically distributed around this elementary wave 59. This means that the pressure maximum of the wavefront of the elementary waves 57 emanating from the multiple acoustic centers (i.e., acoustic centers at the air outlets of the distributed channels of the acoustic low-pass filter device) is in phase with the single elementary wave 59. Thus, the jointly formed wavefront remains homogeneous. A joint synthesized wavefront 4 is generated. Bezugszeichenliste

[0135] 1 Transducer Arrangement 11 First Transducer 12 Second Transducer 211 Acoustic Center of the First Transducer 212 Acoustic Center of the Second Transducer 311 Elementary Wave of the First Transducer 312 Elementary Wave of the Second Transducer 3111 Propagation Direction of the Elementary Wave of the First Transducer 3121 Directional Characteristic of the Second Transducer 4 Synthesized Wavefront 5 Acoustic Low-Pass Filter Device 51 Air Chamber of the Acoustic Low-Pass Filter Device 52 Throat / Constriction of the Acoustic Low-Pass Filter Device 521 Throat Opening 53 Resilient Air Volume 54 Oscillating Air Mass 511 Cone 512 Further Air Chamber 531 Cone Volume 532 Further Air Volume 55 Plate 551 Opening in the Plate 56 Air Outlets 57 Elementary Wave of the Acoustic Centers at the Air Outlets of the Acoustic Low-pass filter device 58 common acoustic center of the first and second transducers 59 elementary wave of the secondTransducer in the acoustic center of the acoustic low-pass filter of the first transducer 6 Pattern 611 first pattern 612 second pattern 7 Three-way module 71 Midrange transducer 711 Chamber volume of the midrange transducer 72 Dome transducer 721 Dome of the dome transducer 73 Bass transducer 731 Front channel of the bandpass 7311 Front volume of the bandpass 732 Rear channel of the bandpass 7321 Rear volume of the bandpass 8 Direction towards a distant listener 81 Main axis of the transducer arrangement 9 Elementary waves of the second transducer

Claims

1. A sound transducer arrangement according to the principle of wave field synthesis for aligning at least one acoustic wavefront, characterized in that at least one first sound transducer (11) is configured as a midrange sound transducer, as a low-midrange sound transducer and / or as a low-range sound transducer and is coupled to a respective acoustic low-pass filter device (5) which comprises a Helmholtz resonator (5), and a plurality of the first sound transducers (11) of the same or different type is arranged in a first pattern (611) relative to one another, in particular in a grid pattern, and high-range sound transducers as second sound transducers (12) are arranged in a second pattern (612) relative to one another, in particular in a grid pattern, and wherein the acoustic centers (211) of the first sound transducers (11) and of the respective acoustic low-pass filter device (5) coupled to the same are arranged in a common area, namely a plane with the acoustic centers (212) of the high-range sound transducers of the second sound transducers (12).

2. The sound transducer arrangement (1) according to claim 1, characterized in that the at least one acoustic low-pass filter device (5) comprises a resilient air volume in an air chamber (51) in front of the respective first sound transducer (11), wherein in particular a cone volume (511) of the at least one first sound transducer (11) is part of or corresponds to the air chamber (51).

3. The sound transducer arrangement (1) according to at least one of the preceding claims, characterized in that the at least one acoustic low-pass filter device (5) comprises a vibrating air mass (54) in a neck or a comparable narrowing of the air outlet (52), wherein in particular an opening (551) in a plate (55) in front of the respective at least one first sound transducer (11) is configured as an opening (54) of the neck (52) of the at least one acoustic low-pass filter device (5) or as the neck (52) itself, and / or the neck (53) of the at least one acoustic low-pass filter device (5) comprises a circular cross-section, and / or the neck (53) of the at least one acoustic low-pass filter device (5) comprises a polygonal cross-section or corresponds to an opening in the sound transducer arrangement (1) which is arranged in front of the at least one first sound transducer (11).

4. The sound transducer arrangement (1) according to claim 1, characterized in that the first pattern (611) and the second pattern (612) represent a superposition of two grid patterns (6).

5. The sound transducer arrangement (1) according to claim 1, characterized in that the at least one Helmholtz resonator (5) has the property that the numerical value S V ⋅ L of the ratio of the area of the outlet opening (54) to the product of the volume of its air chamber (51) and the length of its neck (53) is between 100 to 5000, wherein the area and the volume are indicated in square and cubic meters, respectively, and the length of the neck is indicated in meters.

6. The sound transducer arrangement (1) according to at least one of the preceding claims, characterized in that the first acoustic center (211) of the respective first sound transducer (11) is displaced by the at least one acoustic low-pass filter device (5), in particular for adjusting the spatial emission characteristic of the sound transducer arrangement (1) for a homogeneous structure of the elementary waves (312, 311) of the sound transducer arrangement, wherein in particular the direction of the displacement of the first acoustic centers (211) of the first sound transducer (11) is collinear to the propagation direction of an elementary wave (311) generated by the at least one first sound transducer (11) and / or the displaced acoustic center (211) of the at least one first sound transducer (11) is located on the level of a second sound transducer (12) of the sound transducer arrangement (1).

7. The sound transducer arrangement (1) according to at least one of the preceding claims, characterized in that driving at least one second sound transducer (12) of the sound transducer arrangement (1) is implemented to compensate for an additional phase rotation of a signal of the at least one first sound transducer (11), which is produced by coupling to the acoustic low-pass filter device (5) so that the elementary waves (311, 312) are superimposed to form a common wavefront (4).

8. The sound transducer arrangement (1) according to at least one of the preceding claims, characterized in that the cut-off frequency of the at least one acoustic low-pass filter device (5) is tunable above a crossover frequency of a transmission range of the respective at least one first sound transducer (11).

9. The sound transducer arrangement (1) according to at least one of the preceding claims, characterized in that the outlet of an air channel with its vibrating air mass, which, as the acoustic center, is the origin of the elementary wave of the at least one first sound transducer together with a loudspeaker chassis and the acoustic low-pass, terminates in the plane of the acoustic centers of second sound transducers, in particular of high-range sound transducers.

10. The sound transducer arrangement (1) according to at least one of the preceding claims, characterized in that the at least one acoustic low-pass filter device (5) is configured to be depending on one of the second sound transducers to influence the cut-off frequency of one of the first sound transducers (11) and that of the upstream acoustic low-pass filter device (5) when it is mounted completely or partially in the region of the air outlet of the acoustic low-pass filter device (5).

11. The sound transducer arrangement (1) according to at least one of the preceding claims, characterized in that one of the second sound transducers (12) can be oriented differently, deviating from the main axis of the system, with the aim of linearizing the reproduction for remote listeners (8) which are located far away from the main axis (81) in the emission direction of the array.

12. The sound transducer arrangement (1) according to at least one of the preceding claims, characterized in that the sound transducer arrangement (1) comprises at least one three-way module (7), - which comprises dome-shaped high-range sound transducers (72) which can be used for audio transmission of the upper frequency spectrum and which are mounted in groups on printed circuit boards such that their distance is less than the mutual distance of the midrange loudspeakers, in order to ensure a reproduction which is largely free of aliasing effects, and - which comprises at least one bass sound transducer (73) which is arranged behind the high-range sound transducers (72) and midrange sound transducers (71) and the generated sound pressure of which can be implemented as a double-ventilated bandpass (731, 732).

13. A modular sound transducer system, characterized by at least two sound transducer arrangements (1) according to at least one of claims 1 to 12 as modules, wherein in particular the at least two sound transducer arrangements (1) are arranged such that the emission areas of the respective sound transducer arrangements are arranged in a plane, are part of a curved area or approximate a curved area.

14. A method for operating a sound transducer arrangement (1) according to the principle of wave field synthesis, characterized in that a signal of the at least one first sound transducer system (11) of the sound transducer arrangement (1) is filtered with a respective acoustic low-pass filter device (5), wherein the at least one acoustic low-pass filter device (5) is configured as a Helmholtz resonator, and a plurality of first sound transducers (11) of the same or different type is arranged in a first pattern (611) relative to one another, in particular in a grid pattern, wherein the first sound transducers (11) are configured as midrange sound transducers, as low-midrange sound transducers and / or as low-range sound transducers, and high-range sound transducers as second sound transducers (12) are arranged in a second pattern (612) relative to one another, in particular in a grid pattern, wherein the second sound transducers (12) are configured as high-range sound transducers, and wherein the acoustic centers (211) of the first sound transducers (11) and of the respective acoustic low-pass filter device (5) coupled to the same are arranged in a common area, namely a plane with the acoustic centers (212) of the high-range sound transducers of the second sound transducers (12).

15. The method according to claim 14, characterized by driving at least one second sound transducer (12) of the sound transducer arrangement (1) to compensate for an additional phase rotation of a signal of the at least one first sound transducer (11, 5, 211), which is produced by coupling to the acoustic low-pass filter device (5) so that the elementary waves (311, 312) are superimposed to form a common wavefront (4).

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