SPEAKER SYSTEM WITH REDUCED REAR SOUND EMISSIONS OVER A WIDE FREQUENCY RANGE

Abstract

A loudspeaker system comprises a front-facing loudspeaker enclosure with at least one first loudspeaker and a rear-facing loudspeaker enclosure with at least one second loudspeaker. The rear-facing loudspeaker enclosure is a bandpass enclosure with at least one first chamber and at least one second chamber. The first chamber has a first sound output, and the second chamber has a second sound output. The first and second sound outputs are offset from each other relative to a main radiation direction of the front-facing loudspeaker enclosure.

Description

[0001] The invention relates to a loudspeaker system with directional effect.

[0002] Loudspeaker systems with a low-frequency sound source typically exhibit only low directivity (directionality). This is due to the fact that lower frequencies in the audio frequency range have wavelengths comparable to or larger than the typical cabinet dimensions of the loudspeaker boxes. Sound with a frequency of 100 Hz, for example, has a wavelength of 3.43 m. If the dimensions of a loudspeaker box are significantly below this, this frequency is radiated more or less omnidirectionally. If, for example, a radiation pattern of 90° (with a -6 dB level relative to the main axis) is required, a loudspeaker box with, say, a 1 m width can no longer deliver this directivity in the horizontal plane below approximately 300 Hz.

[0003] In sound reinforcement technology, especially for large-scale or outdoor events, it is desirable to be able to supply a defined audience area with sound pressure as evenly as possible using a single loudspeaker, and this should be as evenly distributed as possible across the defined audience area and across as many frequency bands relevant for transmission as possible (e.g., 40 Hz to 16 kHz). Ideally, the directivity of the loudspeaker system should be constant across the entire frequency range. This means that, especially in the low frequency range, measures that increase the directivity of a loudspeaker system (with given cabinet dimensions) are desirable.

[0004] In addition to ensuring the most even sound distribution possible for a defined audience area, increased directivity can also be important for noise control, as it reduces sound emissions in undesirable directions. Increased directivity also reduces rearward sound radiation, allowing, for example, less sound distribution on a stage and thus higher maximum gain before feedback sets in.

[0005] To reduce rear sound, the use of so-called cardioid loudspeaker arrangements is already known. Cardioid loudspeaker arrangements use a woofer located at the rear of the loudspeaker cabinet, which generates a counter-noise to the sound emitted from the front. This counter-noise cancels out the sound component emitted rearward by the front woofer and amplifies the sound component emitted forward by the front woofer.

[0006] DE 10 2006 058 009 B3 describes a cardioid loudspeaker system with a bandpass loudspeaker as the rear loudspeaker cabinet.

[0007] DE 33 175 518 A1 describes a loudspeaker system with a rear loudspeaker cabinet that has two chambers with respective sound outlets located on the front of the loudspeaker system.

[0008] US 2017 / 0 289 675 A1 shows a loudspeaker system with a rear speaker cabinet consisting of two chambers. The sound outputs of the chambers are arranged without offset relative to a distance measured in the main radiation direction of the front speaker.

[0009] CN 1 06 331 939 A shows a strip-shaped loudspeaker system with front-facing loudspeaker cabinets and a rear-facing loudspeaker cabinet consisting of two chambers, which is designed as a bandpass cabinet.

[0010] One object underlying the invention can be seen in the creation of an improved loudspeaker system with reduced rear sound radiation.

[0011] The problem underlying the invention is solved by the features of patent claim 1. Further developments and embodiments of the invention are the subject of the dependent claims.

[0012] Accordingly, an embodiment of a loudspeaker system can have a front loudspeaker enclosure with at least a first loudspeaker and a rear loudspeaker enclosure with at least a second loudspeaker. The rear loudspeaker enclosure is a bandpass enclosure with at least one first chamber and at least one second chamber. The first chamber has a first sound output, and the second chamber has a second sound output. The first sound output and the second sound output are offset from one another, based on a distance measured in the main radiation direction of the front loudspeaker enclosure. Both the first loudspeaker and the second loudspeaker are woofers or low-midrange loudspeakers.

[0013] A further embodiment of a loudspeaker system has a front loudspeaker enclosure with at least one first loudspeaker and a rear loudspeaker enclosure with at least one second loudspeaker. The rear loudspeaker enclosure is a bandpass enclosure with at least one first chamber and at least one second chamber. The first chamber has a first sound output and the second chamber has a second sound output. The first sound output and the second sound output are offset from one another with respect to a distance measured in the main radiation direction of the front loudspeaker enclosure. The first chamber has a plurality of first sound outputs and / or the second chamber has a plurality of second sound outputs. The plurality of first sound outputs and / or the plurality of second sound outputs are arranged symmetrically to a plane containing the main radiation direction.

[0014] The offset arrangement of the sound outputs ensures that the condition for backsound cancellation is met for different frequencies of the bandpass enclosure. This results in uniform, high attenuation of the backsound across an extended bandwidth range. In other words, the frequency dependence of the cardioid directivity of the loudspeaker system is reduced, thereby expanding the application range of the loudspeaker system, particularly for higher frequencies (e.g., bass-midrange systems). It is also possible to add a tweeter to the loudspeaker system according to the invention and thus design it, for example, as a full-range loudspeaker system that transmits across the entire audio frequency range (e.g., 40 Hz to 16 kHz).

[0015] The bandpass enclosure can comprise at least one first resonator and at least one second resonator with different resonance frequencies f1 and f2, respectively, wherein the first resonator comprises the first chamber with the first sound output, and the second resonator comprises the second chamber with the second sound output. Since different frequencies for reverberation reduction have different path length differences between sound diffracted around the loudspeaker system and directly radiated sound, the offset arrangement of the first and second sound outputs can achieve improved damping over an expanded frequency range.

[0016] If f1 < f2, the first sound output should be located further away from the front loudspeaker cabinet than the second sound output, relative to the main radiation direction.

[0017] The two resonant frequencies f1 and f2 can vary over a wide range. The ratio of the resonant frequencies f2 / f1 is preferably approximately 1.5 to 4, in particular approximately 2 to 3.

[0018] The loudspeaker system can be designed as a low-frequency loudspeaker system (e.g., a subwoofer). In this case, f1 can be in a range of 30 to 50 Hz, for example, and f2 can be in a range of 70 to 110 Hz, for example.

[0019] Alternatively or additionally, the loudspeaker system can also be designed as a low-midrange loudspeaker system. Since the offset of the sound outputs allows for high attenuation of, for example, well over an octave, the rear sound cancellation can also be used in low-midrange loudspeaker systems. For low-midrange loudspeaker systems, f1 can be in a range from 50 to 90 Hz, for example, and f2 can be in a range from 150 to 250 Hz.

[0020] An advantageous structural realization, for example, is that the first sound output is arranged on a rear wall of the rear loudspeaker cabinet.

[0021] The second sound output, which is offset from the first sound output, can be arranged, for example, on a side wall of the rear loudspeaker cabinet.

[0022] If the distance between a front wall of the front-facing loudspeaker cabinet and the first sound output, relative to the main radiation direction, is L1, and the distance between the front wall of the front-facing loudspeaker cabinet and the second sound output is L2, L2 / L1 ≈ f1 / f2 can be set. This approximately matches the resonance frequencies and sound paths.

[0023] If the first chamber and / or the second chamber each have a plurality of first and / or second sound outputs, respectively, a symmetrical radiation behavior can be achieved in a simple manner, for example by arranging the plurality of second sound outputs symmetrically to a plane containing the main radiation direction.

[0024] The first sound output may comprise a first sound reflex tube (e.g., a bass reflex tube) and / or the second sound output may comprise a second sound reflex tube (e.g., a bass reflex tube). In particular, the bandpass enclosure may be designed as a double bass reflex enclosure.

[0025] The front-facing loudspeaker enclosure can also be ventilated (i.e., not closed, but open to the outside through one or more openings, usually realized as tubes). This enables loudspeaker systems with higher efficiency above the resonant frequency of the resonator (formed by the enclosure and the sound reflex tube).

[0026] Embodiments and exemplary embodiments of the invention are explained in more detail below with reference to the drawings. Like reference numerals designate identical or similar parts. Features of the illustrated exemplary embodiments can be selectively combined with one another, provided they are not alternative or technically exclusive features. Furthermore, features of the exemplary embodiments can be selectively omitted unless they are described in the description as mandatory features. Fig. Figure 1 shows a schematic representation of the principle of rear sound reduction in a loudspeaker system shown in plan view with front and rear loudspeaker cabinets. Fig. Figure 2 shows a schematic top view of the structure of an exemplary loudspeaker system with reduced rear sound radiation over an extended bandwidth range. Fig. Figure 3 shows a schematic top view of the structure of another exemplary loudspeaker system with reduced rear sound radiation over an extended bandwidth range. Fig. Figure 4 shows a schematic top view of the structure of another exemplary loudspeaker system with reduced rear sound radiation over an extended bandwidth range.

[0027] Exemplary embodiments of loudspeaker systems are described below. The term "loudspeaker system" can refer to a loudspeaker box in which the front loudspeaker cabinet and the rear loudspeaker cabinet as well as, for example, cabling, crossover(s), insulation materials, connection sockets, power amplifiers (in so-called self-powered systems), etc. are housed. The term "speaker system" can also refer, for example, to a system that includes or consists of multiple loudspeaker cabinets, such as a system in which the front and rear loudspeaker cabinets each represent a loudspeaker box and these are arranged relative to one another or connected to one another in the manner described below.

[0028] Fig. Figure 1 shows a schematic representation of the principle of rear sound reduction in a loudspeaker system 100 with a front loudspeaker enclosure 120 and a rear loudspeaker enclosure 140, viewed from above (e.g., with the ceiling removed). The front loudspeaker enclosure 120 has a first loudspeaker 122, and the rear loudspeaker enclosure 140 has a second loudspeaker 142. The main radiation direction of the front loudspeaker enclosure 120 is designated by X.

[0029] The distance L between the front and rear sound sources is important for the attenuation or cancellation of the rear sound (in the radiation direction -X). For example, this distance L can be given by the distance between a front wall 124 of the front loudspeaker cabinet 120 and a rear wall 144 of the rear loudspeaker cabinet 140.

[0030] The distance L between the front sound source and the rear sound source allows the sound emitted by the two loudspeakers 122, 142 to be added at the front in the main radiation direction X, while the sound emitted by the two loudspeakers 122, 142 at the rear is largely cancelled out against the main radiation direction X. This is Fig. 1 by the front and rear sound signals, where F1 denotes the sound radiated from the front by the first loudspeaker 122, F2 denotes the sound radiated from the front by the second loudspeaker 142, R1 denotes the sound radiated from the rear by the first loudspeaker 122 and R2 denotes the sound radiated from the rear by the second loudspeaker 142.

[0031] Fig. 1 also illustrates that the first loudspeaker 122 may be more powerful than the second loudspeaker 142 because the sound R1 is attenuated as it travels around the loudspeaker system 100.

[0032] Sound cancellation of the superimposed rear sound RS with simultaneous addition of the sound components at the front (FS) can be achieved if the effective path difference dL between sound R1 diffracted around the loudspeaker system 100 and sound R2 radiated directly to the rear is dL = λ / 4. In this case, the path difference dL between sound F2 diffracted around the loudspeaker system 100 and sound F1 directly radiated is also approximately dL = .λ / 4.

[0033] It should be noted that the effective path difference dL is slightly larger than the distance L between the front wall 124 and the rear wall 144, since the majority of the sound wave circulates the loudspeaker system 100 at a certain distance depending on its wavelength. Furthermore, the effective path difference is frequency-dependent. At low frequencies, dL increases relative to L.

[0034] To achieve sound cancellation in the rear radiation direction, R1 and R2 must be in antiphase at the desired cancellation location.

[0035] To achieve this, one possibility is to operate the second loudspeaker 142 with a loudspeaker signal that is in phase opposition to the loudspeaker signal used to operate the first loudspeaker 122, and is also delayed by a time delay Δt=(λ / 4)×1 / c relative to the latter (in other words, the second loudspeaker 142 "waits" for the sound R1 arriving from the first loudspeaker 122). The phase opposition is typically achieved by reversing the polarity of the loudspeaker inputs of the loudspeaker 142. This results in the following wavelength difference for the rear sound RS: λ / 2(reverse polarity)+λ / 4(time delay Δt) − λ / 4(travel dL) = λ / 2, which corresponds to a phase difference of 180° and thus fulfills the condition for sound cancellation. Here, c denotes the speed of sound in air and λ is a considered wavelength of the sound.

[0036] For the front sound FS the wavelength difference is: λ / 2(reverse polarity) + λ / 4(time delay Δt) + λ / 4 (travel dL) = λ, which leads to the in-phase (phase difference 360°) addition of the signals F1 and F2.

[0037] Alternatively, rear sound cancellation and front sound amplification can also be achieved by operating the second loudspeaker 142 in phase (i.e., with correct polarity) and delaying the loudspeaker signal for the first loudspeaker 122 by a time delay Δt = (λ / 4) ×1 / c relative to the loudspeaker signal of the second loudspeaker 142. In this case, the first loudspeaker 122 "waits" for the sound arriving from the second loudspeaker 142. This procedure is also referred to as "end-firing."

[0038] All previously known systems for reducing rear sound radiation have in common that the conditions for canceling the rear sound RS (opposite phase of R1 and R2) while simultaneously adding the front sound FS (in phase of F1 and F2) are only well met for a relatively narrow frequency range (corresponding to a relatively narrow wavelength range). This leads to a deterioration of the attenuation (i.e., the level difference (in decibels) between FS and RS) the further the transmitted frequency deviates from the ideal frequency for maximum attenuation, f = c / (dL×4).

[0039] If a bandpass enclosure is used as the rear loudspeaker enclosure 140, this does not change the described frequency dependence of the attenuation. Although the bandpass enclosure, when combined with a suitable front loudspeaker enclosure and suitable enclosure dimensions, makes it possible to dispense with reverse polarity of the first or second loudspeaker 122 or 142 and / or a time delay in the drive signal of the first and / or second loudspeaker 122 or 142 (i.e., the two loudspeakers 122, 142 can be driven with the same loudspeaker signal), the strong frequency dependence of the attenuation remains. And thus, the significant deterioration in the rear sound reduction also remains the further the transmitted frequency deviates from the ideal frequency f = c / (dL×4).

[0040] In the exemplary loudspeaker system 200 of the Fig. 2, the front loudspeaker cabinet 120 can be mounted as shown in Fig. 1. The rear loudspeaker enclosure 140 is a bandpass enclosure 240. The bandpass enclosure 240 has a first chamber 240_1 and a second chamber 240_2. The first chamber 240_1 has a first sound outlet 241, and the second chamber 240_2 has a second sound outlet 242. The first and second sound outlets 241, 242 are enclosure openings that connect the interior of the respective enclosure chambers 240_1 and 240_2, respectively, with the outside air. Such externally connected chambers 240_1, 240_2 are also referred to as "ventilated" chambers. The rear loudspeaker enclosure 140 of the loudspeaker system 200 can thus be referred to as a double-ventilated bandpass enclosure 240.

[0041] The bandpass enclosure 240 forms an acoustic double resonator that implements a 6th-order acoustic bandpass filter. The second loudspeaker 142 can be located, for example, on a partition wall 244 between the two chambers 240_1 and 240_2.

[0042] The first sound output 241 can be located, for example, on a rear wall 246 of the rear loudspeaker enclosure (bandpass enclosure 240). The second sound output 242 is offset from the first sound output 241 with respect to the main radiation direction X of the front loudspeaker enclosure 120. The second sound output 242 can be located, for example, on a side wall 248A of the rear loudspeaker enclosure (bandpass enclosure 240).

[0043] The different positions of the first sound output 241 and the second sound output 242 with respect to the main radiation direction X are shown in Fig. 2 by different distances L1 and L2, at which the respective sound outputs 241 and 242 are spaced from the front sound source. The front sound source can, for example, correspond to the location of the sound output on the front loudspeaker enclosure 120, which is defined by the front wall 124 of the front loudspeaker enclosure 120. For example, the distance L1 can be measured between a center of the first sound output 241 and the front wall 124 of the front loudspeaker enclosure 120, while the length L2 is measured as the distance between a center of the second sound output 242 and the front wall 124 of the front loudspeaker enclosure 120.

[0044] As already mentioned, the bandpass enclosure 240 implements a double resonator with two different resonance frequencies f1 and f2. The resonance frequencies f1 and f2 are determined by the respective chamber volumes and, if present, by the geometric design (length, diameter, volume, etc.) of the (optional) sound reflex tubes (in Fig. 2 not shown) at the respective sound outputs 241 and 242.

[0045] It can be provided that the first sound output 241 is located further away from the front loudspeaker housing 120 than the second sound output 242 if the resonance frequency f1 of the first chamber 240_1 is smaller than the resonance frequency f2 of the second chamber 240_2.

[0046] In other words, for f1 < f2, the positions of the sound outputs 241, 242 can be selected according to L1 > L2. This means that a lower frequency is emitted at the sound output located further back (here, the first sound output 241) than at the sound output (here, the second sound output 242) located further forward (where "further back" and "further forward" refer to the main radiation direction X).

[0047] In one embodiment, a lower frequency f1 is radiated to the rear (first sound output 241) than to the side (second sound output 242), where the second chamber 240_2 radiates with the higher resonance frequency f2.

[0048] dL1 and dL2 denote the actual propagation path differences between the sound emitted from the respective sound outputs 241 and 242 and the directly emitted sound. The geometric offset L1 - L2 of the first and second sound outputs 241, 242 can be selected such that f1 / f2 = dL2 / dL1. In this case, the propagation path condition (λ / 4 criterion) for rear sound cancellation is "ideally" met for the frequencies f1 and f2. Since the frequencies f1 and f2 are different and the propagation path condition (λ / 4 criterion) is approximately met in the intermediate frequency range, rear sound cancellation is achieved over a broader frequency range.

[0049] This also allows the 200 speaker system to be used in higher frequency speakers (e.g. bass-midrange speakers), ie it is not limited to subwoofers (pure bass speakers).

[0050] For example, the geometric offset L1 - L2 can be set according to L2 / L1 ≈ f1 / f2. For example, L2 / L1 = (f1 / f2)±30%, L2 / L1 = (f1 / f2)±20%, or L2 / L1 = (f1 / f2)±10% can be set, whereby any value within the specified ranges can be selected for the ratio L2 / L1. As already mentioned, dL1 > L1 and dL2 > L2. Furthermore, dL1 - L1 > dL2 - L2 applies, since f1 is smaller than f2 and thus the distance at which sound of frequency f1 travels around the loudspeaker system 200 is greater than for sound of frequency f2. In addition, the f2 resonator output 242 is radiated laterally, for example, ie the sound does not have to be bent by 180° around the loudspeaker system 200, but only by 90°.

[0051] By selecting the resonance frequencies f1 and f2, the frequency range in which increased backsound cancellation (improved damping) can be achieved can be adjusted. In other words, the frequency dependence of the directivity of the loudspeaker system 200 can be specifically influenced. For example, the ratio f2 / f1 can be set in a range from 1.5 to 4, in particular from 2 to 3.

[0052] For a bass loudspeaker system 200, f1 can, for example, be in a range from 30 to 50 Hz (e.g., approximately 40 Hz), and f2 can, for example, be in a range from 70 to 110 Hz (e.g., approximately 90 Hz). If the loudspeaker system 200 is a bass-midrange loudspeaker system, for example, higher resonance frequencies f1 and f2 are realized in the bandpass enclosure 240. For example, f1 can be in a range from 50 to 90 Hz (e.g., approximately 70 Hz), and f2 can be in a range from 150 to 250 Hz (e.g., approximately 200 Hz).

[0053] As already mentioned, by using a bandpass enclosure 240 as the rear loudspeaker enclosure 140 it can also be achieved that (unlike the loudspeaker system 100 of the Fig. 1) The first loudspeaker 122 and the second loudspeaker 142 can be operated with the same drive signal. This means that a time delay Δt in one of the drive signals for the loudspeakers 122, 142 can optionally be omitted.

[0054] In other embodiments, the control signals for the first loudspeaker 122 and the second loudspeaker 142 are different, for example by reversing the polarity of one of the loudspeakers 122, 142 and / or by introducing a time delay Δt in the control signal of one of the loudspeakers 122, 142, for example as described for Fig. 1 was described.

[0055] Fig. 3 shows a loudspeaker system 300 that differs from loudspeaker system 200, for example, in that a plurality of first sound outputs 241 and / or a plurality of second sound outputs 242 can be provided. For example, the plurality of first sound outputs 241 and / or a plurality of second sound outputs 242 are arranged symmetrically with respect to a plane containing the main radiation direction X (which, for example, runs perpendicular to the plane of the paper). This achieves symmetrical radiation with respect to the main radiation direction X for both the rear-side sound RS and the front-side sound FS. The two second sound outputs 242 of the second chamber 240_2 can, for example, be arranged on opposite side walls 248A, 248B of the bandpass housing 240.

[0056] Furthermore, Fig. 3, the first sound output 241 and / or the second sound output 242 can be designed as sound reflex tube(s) D1 and D2, respectively. In this case, the resonance frequencies f1 and f2 are influenced both by the respective chamber volume and by the geometry of the respective sound reflex tube(s) D1 and D2, respectively. For example, a sound reflex tube D1 of the first sound output 241 can have a larger diameter and / or a larger volume than a sound reflex tube D2 of the second sound output 242.

[0057] In the Fig. 3, the partition wall 244 is oriented, for example, perpendicular to the main radiation direction X. The first chamber 240_1 can be, for example, the rear chamber of the bandpass housing 240, while the second chamber 240_2 in this case represents the front chamber of the bandpass housing 242. However, the partition wall 244 can also be oriented inclined to the main radiation direction X or - as in Fig. 2 - run parallel to it.

[0058] The front-facing loudspeaker enclosure 120 of the loudspeaker system 300 is designed, for example, as a ventilated enclosure, i.e., in this case, it contains at least one sound reflex tube D3 (or two or more sound reflex tubes D3). The sound reflex tube D3 can have a larger volume and / or diameter than the sound reflex tube D1 of the bandpass enclosure 240. Furthermore, the chamber volume of the front-facing loudspeaker enclosure 120 can be larger than the sum of the chamber volumes of the bandpass enclosure 240.

[0059] As already mentioned, the first loudspeaker 122 can be more powerful than the second loudspeaker 142 because the sound R1 radiated from the rear of the first loudspeaker 122 loses intensity (sound pressure level) as it travels around the loudspeaker system 300.

[0060] In Fig. 3, R2_1 denotes the sound emitted by the second loudspeaker 142 at the rear at a first sound output 241, R2_2 denotes the sound emitted by the second loudspeaker 142 at the rear at the second sound output 242, F2_1 denotes the sound emitted by the second loudspeaker 142 at the front at the first sound output 241, and F2_2 denotes the sound emitted by the second loudspeaker 142 at the front at the second sound output 242. dL1 denotes the actual travel path difference between R1 and R2_1, and dL2 denotes the actual travel path difference between R1 and R2_2.

[0061] The condition for "ideal" rear sound attenuation at frequencies f1 and f2 is also f1 / f2 = λ2 / λ1 = dL2 / dL1. Approximate rear sound cancellation can be achieved between frequencies f1 and f2.

[0062] In the loudspeaker system 300, the two resonators (or chambers 240_1, 240_2) of the bandpass housing 240 are arranged one behind the other with respect to the main radiation direction X. In other examples, the resonators of the bandpass housing 240 can be arranged side by side. Fig. 4 shows an example of a loudspeaker system 400, which has, for example, a plurality of first loudspeakers 122 and / or a plurality of second loudspeakers 142. The loudspeaker system 400 is essentially implemented by mirroring the Fig. 2 on the upper housing wall. To avoid repetition, reference is made to the above description.

[0063] As with the 300 speaker system in Fig.3, a symmetrical radiation pattern is achieved. In the bandpass enclosure 240 of the loudspeaker system 400, for example, a common chamber 240_1 is provided for the resonator of frequency f1 (separate chambers of the same frequency f1 would also be possible). On either side of this resonator (or the corresponding chamber 240_1) are two resonators (or chambers 240_2) of frequency f2 with sound outputs 242 suitably offset from the rear wall. The (ideal) cancellation of the rear sound RS at frequencies f1 and f2 and the simultaneous (ideal) addition of the sound components of the front sound FS occur in the manner already described.

[0064] What all embodiments have in common is that the geometrically offset arrangement of the sound outputs 241, 242 of the bandpass housing 240 enables uniform, high attenuation over a wide frequency range (e.g., significantly more than one octave).

Claims

[1] Loudspeaker system with a front loudspeaker cabinet (120) with at least one first loudspeaker (122), and a rear speaker cabinet (140) with at least one second speaker (142), wherein the rear loudspeaker enclosure (140) is a bandpass enclosure (240) with at least one first chamber (240_1) and at least one second chamber (240_2), the first chamber (240_1) has a first sound output (241), the second chamber (240_2) has a second sound output (242), and the first sound output (241) and the second sound output (242) are arranged offset from one another with respect to a distance measured in the main radiation direction (X) of the front loudspeaker housing (120), wherein both the first loudspeaker (122) and the second loudspeaker (142) are woofers or low-midrange loudspeakers. [2] Loudspeaker system according to claim 1, wherein the bandpass enclosure (240) comprises at least one first resonator and at least one second resonator with different resonance frequencies f1 and f2, respectively, wherein the first resonator comprises the first chamber (240_1) with a first sound output (241) and the second resonator comprises the second chamber (240_2) with a second sound output (242). [3] Loudspeaker system according to claim 2, wherein the first sound output (241) is located further away from the front loudspeaker cabinet (120) with respect to the main radiation direction (X) than the second sound output (242), and f1 < f2. [4] Loudspeaker system according to one of claims 2 or 3, wherein f2 / f1 is in a range from 1.5 to 4, in particular from 2 to 3. [5] Loudspeaker system according to one of claims 2 to 4, wherein the loudspeaker system is designed as a bass loudspeaker system and f1 is in a range of 30 to 50 Hz and f2 is in a range of 70 to 110 Hz. [6] Loudspeaker system according to one of claims 2 to 4, wherein the loudspeaker system is designed as a low-midrange loudspeaker system and f1 is in a range of 50 to 90 Hz and f2 is in a range of 150 to 250 Hz. [7] Loudspeaker system according to one of claims 2 to 6, wherein, with respect to the main radiation direction (X), a distance between a front wall of the front-side loudspeaker housing (120) and the first sound output (241) is L1, a distance between the front wall of the front-side loudspeaker housing (120) and the second sound output (242) is L2, and L2 / L1 ≈ f1 / f2. [8] Loudspeaker system according to one of the preceding claims, wherein the first sound output (241) is arranged on a rear wall of the rear loudspeaker cabinet (140). [9] Loudspeaker system according to one of the preceding claims, wherein the second sound output (242) is arranged on a side wall of the rear loudspeaker cabinet (140). [10] Loudspeaker system according to one of the preceding claims, wherein the first chamber (240_1) has a plurality of first sound outputs (241) and / or the second chamber (240_2) has a plurality of second sound outputs (242), and wherein the plurality of first sound outputs (241) and / or the plurality of second sound outputs (242) are arranged symmetrically to a plane containing the main radiation direction (X). [11] Loudspeaker system according to one of the preceding claims, wherein the first sound output (241) has a first sound reflex tube (D1) and / or the second sound output (242) has a second sound reflex tube (D2). [12] Loudspeaker system according to claim 11, wherein a diameter and / or volume of the first sound reflex tube (D1) is larger than a diameter and / or volume of the second sound reflex tube (D2). [13] Loudspeaker system according to one of the preceding claims, wherein the second loudspeaker (142) is arranged on a partition wall (244) between the first chamber (240_1) and the second chamber (240_2). [14] Loudspeaker system according to one of the preceding claims, wherein the first chamber (240_1) and the second chamber (240_2) of the bandpass housing (240) are arranged one behind the other with respect to the main radiation direction (X). [15] Loudspeaker system according to one of claims 1 to 13, wherein the first chamber (240_1) and the second chamber (240_1) of the bandpass housing (240) are arranged laterally next to one another with respect to the main radiation direction (X). [16] Loudspeaker system according to one of the preceding claims, wherein the bandpass housing (240) has a plurality of first chambers (240_1) and / or a plurality of second chambers (240_2). [17] Loudspeaker system according to one of the preceding claims, wherein the front loudspeaker cabinet (120) is ventilated. [18] Loudspeaker system with a front loudspeaker cabinet (120) with at least one first loudspeaker (122), and a rear speaker cabinet (140) with at least one second speaker (142), wherein the rear loudspeaker enclosure (140) is a bandpass enclosure (240) with at least one first chamber (240_1) and at least one second chamber (240_2), the first chamber (240_1) has a first sound output (241), the second chamber (240_2) has a second sound output (242), and the first sound output (241) and the second sound output (242) are arranged offset from one another with respect to a distance measured in the main radiation direction (X) of the front loudspeaker housing (120), wherein the first chamber (240_1) has a plurality of first sound outputs (241) and / or the second chamber (240_2) has a plurality of second sound outputs (242), and the plurality of first sound outputs (241) and / or the plurality of second sound outputs (242) are arranged symmetrically to a plane containing the main radiation direction (X).

Images