A directional sound amplification device with large controlled bandwidth

Abstract

The object of the present application is a loudspeaker comprising a plurality of sound sources and having a large controlled broadband directivity.

Description

[0001] The present application relates to a directional loudspeaker with a large controlled broadband. Prior art

[0002] The goals of a modern sound system are to:

[0003] - Ensure sound level uniformity in the covered listening area, as well as sound level uniformity across the entire audio spectrum (20Hz to 20kHz), while avoiding sound levels outside this area;

[0004] - Ensure a high level of quality for the listener from the point of view of the coupling of the various components that make up the sound system.

[0005] Sound amplification devices that radiate at low frequencies (ie, below 200 Hz) have very poor directivity because of their small size compared to the wavelength produced by the sound source.

[0006] To mitigate this emission, which not only pollutes areas to be avoided but also excites the resonant modes of the room and produces disturbing reverberations for the listeners, users and manufacturers of sound reinforcement systems have invented electroacoustic configurations which impart a particular directivity to the sound device, particularly a cardioid or supercardioid type of directivity. Figure 1 Polar acoustic radiation patterns are shown for different directivity types.

[0007] More precisely, when using a sound system with multiple loudspeakers, seek to direct the sound forward (i.e. Figure 1 The radiation from different amplification devices is effectively superimposed (in the direction of the 0° axis) and directed backward (i.e. Figure 1 Superposition of acoustic radiations from different devices means the superposition of these radiations, resulting in positive or negative areas. Effective superposition is a solution in which the superposition of radiations results in positive areas, i.e. areas in which the radiations do not cancel each other out.

[0008] In the presence of multiple sound sources, the listener will perceive the physical phenomenon of the emitted waves with a time difference caused by the path difference between its position and the position of each sound source, making it possible to conceive of the aforementioned specific directivity design.

[0009] Electronic control of the amplitude and phase of the sound sources enables the radiation pattern to be adjusted, and therefore the directivity of the sound amplification device. In other words, by injecting signals with different phases according to frequency (for example, delay) into these different sound sources, it is possible to control the passive or active area resulting from the superposition of the sound streams of the multiple sound sources used. The power ratio between each of these sound sources also affects the effectiveness of the directivity caused by the setup.

[0010] Configurations that allow for such directivity, either through product assembly or by integrating new sound sources (speakers, vents) into the product. An example of a product assembly could be two sets of subwoofers aligned front to back, or a stack of flipped sources. Figure 2 A set of stacked flipped sources is shown in Figure 3 In this type of group, certain sound sources are directed forward, while others are directed backward.

[0011] In most cases, the physical configuration of the product and / or the components within the product is accompanied by separate adjustments of the amplitude and phase, as well as the electronic control (DSP) for each frequency, to achieve the control function of the directivity. However, depending on the adjustment of the electronic control, the control of the directivity can be more or less frequency-limited. In addition, the superposition of the different elements of the device may be roughly optimal from a positive point of view.

[0012] A first example of prior art is to design Figure 2 The front-to-back alignment of two groups of subwoofers is shown, which is electronically controlled by an "end-fire" adjustment. This control consists in electronically adding a time delay to the front group so that the waves from the front and rear groups arrive at the front axis (marked as the 0° axis) at the same time, so as not to degrade the perceived quality of the sound. For a user located to the rear of the two aligned stacks, the waves from the front group arrive with a delay that is the sum of the path difference of the front group relative to the rear group and the electronically added delay. This delay can be optimized to produce anti-phase between the two groups at the exact sound frequency. The net result of this adjustment is non-existent sound loss in the front, but at the expense of very localized frequency suppression in the rear. The performance of such a system is shown in Figure 1. Figures 4A to 4D As shown: The phase difference curve shows good sound quality in the front, that is, the sound waves from the two groups arrive in phase (0° phase shift) in front, and complete suppression of a single frequency (180° phase shift).

[0013] A second example of prior art is related to Figure 2 The front-to-back alignment of the two groups of bass boxes is shown, which is electronically controlled by the so-called "gradient" adjustment. This control consists in adding an electronic delay to the rear group so that the waves from the front and rear groups arrive at the same time when viewed from the rear, and adding an anti-phase to cancel the sound at the rear. Figures 5A to 5DThe performance of such a system is shown in Figure 1. As shown by the phase difference curve equal to 180° between the front and rear groups, effective suppression is achieved over a wide frequency band. However, for a user located in the front, the waves emitted by the rear group arrive with a constant time delay on the 0° axis. In the phase difference diagram in the direction of the 0° axis, a misalignment of the two groups can be observed over the entire frequency band, except for the frequency where the phase difference is zero. In addition, there is always a constant delay in time between the sound waves from the front group and the rear group, which can produce echoes that are detrimental to the signal quality perceived in the front.

[0014] A third example of the prior art is to design Figure 2 The front-to-back alignment of the two sets of bass enclosures shown is electronically controlled by a so-called "all-pass filter" adjustment. This electronic adjustment acts like a filter that introduces a delay that varies with the frequency of the sound. This adjustment allows a compromise between suppression of the rear over a wide frequency band and an efficient superposition of waves from the front and rear sound sources. Figures 6A to 6D The performance of such a system is shown. The polar plots of directivity at different frequencies are similar. In addition, the phase difference curve at the rear (on the 180° axis) shows a more constant anti-phase over frequency.

[0015] The advantage of a standalone product's physical configuration is that it provides flexibility to the user, who can adjust the physical configuration to meet directionality and sound quality goals; however, it requires a higher level of expertise than products that directly package control functions for directionality and sound quality.

[0016] Therefore, some manufacturers have proposed integrating multiple electronically controlled sources into the sound box. For example, some products have two speaker / vent assemblies in the front and two speaker / vent assemblies in the back. An example of such a product is Figure 7 The disadvantage of such products with multiple sources integrated in the front and rear is that the phase and time alignment of the different sources does not work well at higher frequencies for the listener in front of the loudspeaker. This disadvantage may be acceptable for bass, but is unacceptable for products that reproduce higher frequencies (especially frequencies greater than 60Hz).

[0017] Therefore, a solution known in the prior art consists in making a product that, in addition to having sound sources located in the forward direction, also has sound sources located approximately to the sides, so as to reduce the propagation time of the rearward sources by shortening the spacing between the sources. An example of such a product is Figure 8 shown.

[0018] On the one hand, this product configuration is inherently deficient in the quality of sound amplification achieved. Fig. 9A and 9BThe response curves in dB SPL (Sound Pressure Level) are shown in different listening directions in the front hemisphere of the loudspeaker defined by the main emission direction of the loudspeaker, obtained in a first configuration with the sound sources in the front direction of the loudspeaker and in a second configuration with additional sources in the side directions. The frequency curves show that in the second configuration with additional sources in the side directions, the directivity lobe decays faster towards the sides, which can produce an uneven dispersion among all listeners.

[0019] On the other hand, the disadvantages of products with a sound source located approximately to the side are mechanical. Fig.10 As shown, products with sound sources located approximately laterally cannot be stacked laterally without losing the efficiency of the product; for this type of product, it is also difficult to manufacture a continuous array of products and to connect other objects to the product; finally, the lateral sources are visible from the outside.

[0020] The present invention aims to overcome the drawbacks of the prior art and in particular to improve the quality of the directionality of a product configuration comprising forward and lateral sources.

[0021] Therefore, the object of the present invention is a speaker having a volume shape, the volume shape having a front side, a back side, and two sides, a first side and a second side. The speaker has a main emission direction perpendicular to the front side of the speaker, and a rear emission direction perpendicular to the back side of the speaker. The speaker comprises:

[0022] - at least one forward sound source, which is configured to emit through the front side and has a forward sound source main emission direction, the front sound source main emission direction being substantially identical to the main emission direction of the sound box;

[0023] - at least one lateral sound source, which is oriented toward at least one side with a source, the side with a source being one and / or the other of the first and second sides, the lateral sound source having a lateral source main emission direction perpendicular to one and / or the other of the first and second sides;

[0024] - at least one sound waveguide, the waveguide being located in front of at least one lateral sound source to shield the sound flow emitted from the lateral sound source along the main emission direction of the lateral source, and to guide the sound flow emitted from the lateral sound source to both the first plurality of lateral directions and the second plurality of lateral directions of the main emission direction of the lateral source, and the waveguide being mounted to the side with the source by a mounting device;

[0025] - at least one forward hole formed by the space between the side with the source and the acoustic waveguide, so as to allow the passage of the acoustic flow emitted by the lateral acoustic source in a direction directed towards the hemisphere defined by the main emission direction of the sound box;

[0026] - at least one back-facing hole formed by the space between the side with the source and the acoustic waveguide, so as to allow the passage of the acoustic flow emitted by the lateral acoustic source in a direction directed towards the hemisphere defined by the rear emission direction of the sound box;

[0027] - means for shielding the acoustic flow emitted by said at least one waveguide in directions other than said at least one forward aperture and said at least one backward aperture, so as to enhance the acoustic flow emitted through the forward aperture and the backward aperture.

[0028] Advantageously, at least one forward sound source is located in the front volume.

[0029] In this case, advantageously, at least one lateral sound source is located in a lateral volume separated from the front volume.

[0030] In one or more embodiments, at least one front sound source and at least one lateral sound source are sound sources operating substantially within the same frequency band.

[0031] In one or more embodiments, both the front sound source and the lateral sound source are sound sources operating substantially in a low frequency band and / or a mid frequency band.

[0032] In one or more embodiments, at least one forward sound source and at least one side sound source are configured to be fed separately by multiple DSP and amplification channels and electronically controlled in amplitude and phase to control the directivity of the sound radiation of the speaker.

[0033] In one or more embodiments, the speaker enclosure according to the present invention is suitable for stacking with a second speaker enclosure according to the present invention. Each of the speaker enclosure and the second speaker enclosure further comprises, in one aspect, a first upper surface and a first lower surface, and in another aspect, a second upper surface and a second lower surface. The speaker enclosure can be stacked with the second speaker enclosure from below, above or from the side.

[0034] In one or more embodiments, the loudspeaker according to the invention is of the bass reflex type and further comprises at least one vent associated with at least one lateral sound source. A bass reflex loudspeaker refers to a loudspeaker equipped with one or more vents (also called resonators). In these cases, at least one vent is located on the back of the loudspeaker.

[0035] In one or more embodiments, the device for shielding the acoustic flow connects the side with the source to the acoustic waveguide in a complete and continuous manner above and below the sound box (E).

[0036] Other advantages and features of the invention will emerge from the description given by way of non-limiting example and with reference to the accompanying drawings, in which:

[0037] - Figure 1(described) shows polar radiation patterns corresponding to different types of sound directivity.

[0038] - Figure 2 (described) shows the front-to-back alignment of two sets of bass enclosures.

[0039] - Figure 3 (Described) shows a set of stacked flipped sources.

[0040] - Figures 4A to 4D (described) illustrates the acoustic performance of a prior art sound reinforcement system comprising two sets of sound sources aimed front and back controlled by "end-fire" type electronic controls.

[0041] - Figures 5A to 5D (described) shows the acoustic performance of a prior art sound reinforcement system comprising two sets of sound sources aligned front to back controlled with a "gradient" type electronic control.

[0042] - Figures 6A to 6D (described) shows the acoustic performance of a prior art sound reinforcement system comprising two sets of sound sources aligned front to back controlled with an "all pass filter" type electronic control.

[0043] - Figure 7 (Described) shows a top view of the geometry of a speaker enclosure including sound sources located in front and behind the enclosure.

[0044] - Figure 8 (described) shows a top view of the geometry of a speaker enclosure including a forward sound source and additional sound sources located generally to the sides of the enclosure.

[0045] - Fig. 9A and 9B (described) shows a comparison between the performance of a loudspeaker having only a front source and a loudspeaker having, in addition to the front source, sound sources located generally to the sides of the loudspeaker.

[0046] - Fig.10 (described) schematically shows the stacking of the sides of a loudspeaker with additional sources on the sides.

[0047] - Fig.11A and 11B A three-dimensional view and a two-dimensional top view of the digital model of the sound box according to the present invention are respectively shown.

[0048] - Fig.12 A top view of a schematic diagram of another sound box according to the present invention is shown.

[0049] - Fig.13A and 13B Two graphs showing the SPL values ​​of a loudspeaker without and with an acoustic waveguide.

[0050] - Fig.14A and 14B A comparison of the performance of the sound box E without and with an acoustic waveguide is shown in terms of the difference in phase and amplitude as a function of the sound frequency.

[0051] - Figures 15A to 15D The performance of a loudspeaker E according to a first type of electronic control with a waveguide electronically controlled in amplitude and phase is shown.

[0052] - Figures 16A to 16D The performance of a loudspeaker E electronically controlled in amplitude and phase according to a second type of electronic control is shown.

[0053] Fig.11A -B to 16A-D are discussed in more detail in the following detailed description and examples, which illustrate the invention but do not limit its scope. DETAILED DESCRIPTION

[0054] Fig.11A and 11B A three-dimensional view and a top view of a speaker E according to the present invention are shown. A speaker refers to a housing containing one or more sound sources, which allows sound to be produced based on an electrical signal provided by an audio amplifier. The speaker E has a volume shape defining an inner area of ​​the speaker and an outer area of ​​the speaker (hereinafter referred to as the inner and outer areas of the speaker), which has a front F Eav , back side F Ear and the first side F Elat1 and the second side F Elat2 Two sides. Fig.11A and 11B The case is a parallelepiped. Fig.12 As shown, the speaker can adopt any other volume shape (such as an extruded trapezoid), wherein the first side Elat1 and the second side F Elat2 Not perpendicular to the front of the speaker E F Eav .

[0055] The speaker E has a front F facing the outside of the speaker E. Eav Vertical main emission direction D av , and the rear F facing the outside of the speaker E Ear Vertical rear emission direction D ar In the following, the main emission direction of the loudspeaker E will be referred to as D av or 0° emission axis. Similarly, the rear emission direction of speaker E will be indiscriminately referred to as D ar Or 180° launch axis.

[0056] The sound box E includes at least one forward sound source S av , which is configured to pass through the front FEav At least one forward sound source S av With forward source main emission direction D Sav , which is roughly equivalent to the main emission direction D of speaker E av .

[0057] The sound box E also includes at least one lateral sound source S lat , which faces at least one side F having a sound source Elat , which side corresponds to the first side F of the speaker Elat1 and the second side F Elat2 One and / or the other of the two sides. At least one lateral sound source S lat With side F Elat1 and F Elat2 One and / or the other of the lateral source main emission direction D which is substantially vertical and directed to the outside of the speaker E Slat .

[0058] In one or more embodiments, the forward sound source and the lateral sound source may be placed separately in different volumes, namely, the front volume V SAv and the lateral volume V SLat , realized by the partition C in the sound box E. For at least one source S av and at least one lateral source S lat Preparing different volumes allows for different signal distributions to the enclosures, thereby controlling the directivity of the radiation. An example of these embodiments is Fig.12 As shown. Such volumes allow better diffusion qualities to be obtained because they separate the sound diffusion spaces in which the sound signals sent to the front sound source and the lateral sound source, respectively, are different. Therefore, these volumes can reduce adverse effects (such as interference) that may reduce the diffusion quality of the entire speaker. Various configurations can be adopted: for example, in the case of multiple forward sound sources, each of them can be located in a separate volume, or multiple sound sources can be integrated in the same volume; similarly, in the case of multiple lateral sound sources, each of them can be located in a separate volume, or multiple sound sources can be integrated in the same volume.

[0059] although Fig.11A and 11B A symmetrical loudspeaker with two front sound sources and two side sound sources is shown. Directional effects can also be obtained using a single front sound source and a single side sound source, such as Fig.12 shown.

[0060] The sound box E also includes at least one acoustic waveguide G. An acoustic waveguide is a physical device that can guide an incident acoustic wave flow on itself. For example, the acoustic waveguide G can take the form of a simple wall, or any other three-dimensional shape designed to guide the acoustic flow encountered by the waveguide G in a certain direction. For example, the waveguide can be designed to converge or diverge the acoustic flow incident on the waveguide.

[0061] The waveguide G according to the invention is located at least one lateral sound source S lat in front of the camera to block the sound from at least one lateral sound source S lat In the main emission direction of the lateral source D Slat The acoustic flow F lat , and the acoustic flow F lat Directed to the main emission direction of the lateral source D Slat The first plurality of lateral directions D on both sides Slat1 and a second plurality of lateral directions and D Slat2 The terms first plurality of lateral directions and second plurality of lateral directions refer to the directions of the main emission direction D of the lateral source, respectively. Slat The waveguide G is assembled to the side F with the source by an assembly device. Elat The waveguide G has an outer face and an inner face.

[0062] The speaker E also has at least one forward hole O Slat_av , which is formed by the space between the inner surface of the sound waveguide G and the first inner partition of the sound box E, so that the sound source S lat The emitted acoustic flow F lat Pointing in the main emission direction D av Defines the direction of the hemisphere by. Fig.11A -B and Fig.12 This positive hole O Slat_av .

[0063] Preferably, the forward hole O Slat_av Let at least one sound source S lat The acoustic flow F lat From the positive hole O Slat_av Determine the direction D of the speaker E OSLat_av The direction included in the defined hemisphere passes through. Advantageously, the positive hole O Slat_av Let at least one sound source S lat The acoustic flow F lat Passing in a direction included in a cone having a direction D parallel to the enclosure OSLat_av Axis and half opening angle of 30°. Other arrangements are also possible, in particular including different opening angles.

[0064] The speaker E also has at least one rear-facing hole O SLat_ar, which is formed by the space between the inner surface of the sound waveguide G and the second inner partition of the sound box E, so that the sound source S lat The sound flow (F lat ) in the direction of the rear emission D ar Defines the direction of the hemisphere. Fig.11A -B and Fig.12 This back hole O is shown Slat_ar .

[0065] Preferably, the back hole O Slat_ar At least one sound source S lat The emitted acoustic flow F lat Along the back hole O Slat_ar Determine the direction D of the speaker E Slat_ar The direction included in the defined hemisphere passes through. Advantageously, the back hole O Slat_ar Let at least one sound source S lat The acoustic flow F lat Passing in a direction included in a cone having a direction D parallel to the sound box E OSLat_ar and a half opening angle of 30°. Other arrangements are also possible, in particular including different opening angles.

[0066] Therefore, compared with a speaker without a waveguide, the speaker according to the present invention has at least one acoustic waveguide G, at least one forward hole O, Slat_av and at least one back-facing hole O Slat_ar The Speaker E showcases a new and improved transmitting unit.

[0067] According to one embodiment, the sound box E comprises means for limiting or eliminating the diffusion of the sound flow in directions other than the directions of the at least one forward hole OSlat_av and the at least one rearward hole OSlat_ar.

[0068] According to a particular embodiment, these means may be specifically designed to send the flow towards these holes and thus increase the emitted acoustic flow through these holes and enhance the effect of the studied cardioid directivity.

[0069] According to a particular embodiment, these means may include the inner wall of the above FEsup and the inner wall of FEinf. These inner walls may be designed to be complete and continuous at the space formed by the inner face of the waveguide and the side face (FElat) of the enclosure with the source. Fig.11AIn the example shown with reference numerals Gsup and Ginf in the figure, these means can be obtained by extending the upper or lower wall of the sound box, thereby also allowing the fixing of the sound waveguide G. Therefore, these walls block the sound flow Flat sent by the sound waveguide G in the following directions: on the one hand, perpendicular to the emission direction in the main emission direction Dslat of the lateral source; and, on the other hand, perpendicular to the upper Fesup and the lower Feinf; that is to say, in this example, towards the top or the bottom of the sound box. Therefore, except for at least one forward hole OSlat_av and at least one back hole OSlat_ar, there are no other holes through which the sound flow leaks. Other structures can also be designed to realize these means, in particular shielding elements independent of the upper and lower walls of the sound box E, for example, in the form of inserts.

[0070] According to an embodiment, the speaker E may have symmetry about a plane corresponding to the front face F of the speaker E. Eav In this case, the speaker E has a first plurality of sound sources S lat1 and a second plurality of sound sources S lat1 The first plurality of sound sources are directed toward the side F of the speaker Elat1 The second plurality of sound sources and the plurality of sound sources S lat1 Same as and relative to the front of speaker E F Eav The plane corresponding to the middle plane is symmetrically positioned so that it faces the side F of the speaker E Elat2 Directional.

[0071] Fig.13A and 13B A comparison between a top view of a graph of SPL values ​​(dB response) of a loudspeaker E without a waveguide and a graph of the same loudspeaker E with a waveguide is shown. The graphs are from numerical simulations obtained with the COMSOL Multiphysics software commercialized by COMSOL. The simulations are based on the finite element method. The brightest areas correspond to areas with high SPL values, while the darkest areas correspond to areas with low SPL values. The waveguide is assembled to the side of the loudspeaker with the source (F Elat ) on a flat wall. The enclosure has multiple sources (speakers and vents) located at the front and multiple sound sources (speakers) located at the sides. In the example of Figure 13, the enclosure E is bilaterally symmetrical. It can be observed that, with the waveguide, the sound flow on the right side of the enclosure is reduced compared to the figure of the enclosure without the waveguide G. In addition, the sound level coming out of the back hole is increased.

[0072] Fig.14A and 14B It shows that previously Fig.11A and 11BComparison of the performance of a loudspeaker in terms of modulus and phase difference as a function of frequency between a source facing forward and a source located to the side is shown in Figure 1. The curve corresponds to a listening direction on the 0° axis (i.e. towards the front), therefore towards the audience. A better minimization of the phase difference can be observed in the frequency range between 180 Hz and 310 Hz, which corresponds to a better superposition of the waves emitted by the combination formed by the source facing forward and the source located to the side.

[0073] An arbitrary single commonly used division in the art divides the sound spectrum, which covers at least a portion of the spectrum that can be heard by humans (i.e., 20 Hz to 20 kHz), into three or four frequency bands. The high frequency band (or HF band) covers the highest frequencies corresponding to sharp sounds, generally in the interval between approximately 1 kHz and 20 kHz. The mid-frequency band (or MF band) covers the middle frequencies, generally in the interval between approximately 200 Hz and 1 kHz. The low frequency band (or BF band) covers the low frequencies corresponding to deep sounds, generally in the interval between approximately 60 Hz and 200 Hz. Finally, the too low frequency band (or TBF band) corresponding to too deep or sub-deep sounds covers the frequency interval between approximately 0 Hz and 60 Hz. In practice, the same component can be used to release signals in the BF and MF bands. Generally, a sound source can transmit in multiple frequency ranges, but will be defined by the main emission range of the sound source.

[0074] In one or more embodiments of the speaker E, at least one forward sound source S av and at least one lateral sound source S lat The sound sources generally work in the same frequency band. According to one or more embodiments, the same frequency band includes one or more of the following: a very low frequency band, a low frequency band, a medium frequency band, and a high frequency band.

[0075] According to an embodiment, the same frequency band includes one or more frequency bands except the high frequency band.

[0076] According to a variant embodiment, at least one forward sound source S av and at least one lateral sound source S lat These are sound sources operating in respective frequency bands that partially overlap within an interval where the desired directivity control is located.

[0077] In one or more embodiments of the speaker E, at least one forward sound source S av and at least one lateral sound source S lat The DSP channel feed and the electronic control of amplitude and phase are intended to control the directivity of the sound radiation from the loudspeaker E.

[0078] Therefore, the acoustic flow distribution generated by using at least one waveguide G in the loudspeaker E allows the loudspeaker E to be fed by the DSP channel and to at least one forward sound source S av and at least one lateral sound source S lat Electronic control in amplitude and phase with a wider range of directivity. Waveguide G allows better control and a wider range of directivity for loudspeakers that have side sources in addition to the main source emitting towards the front.

[0079] Two examples will be described below which illustrate the directivity control that can be achieved by using a waveguide in a loudspeaker E with a front source and a side source.

[0080] Example 1: DSP solution with perfect alignment along the axis

[0081] Consider here a symmetrical loudspeaker E with a forward low frequency source and low frequency sources on both sides of the loudspeaker. The sources are fed by a DSP channel and the amplitude and phase are controlled electronically. The control implemented is aimed at the 0° axis D of the loudspeaker E. av Perfect alignment in direction. Figures 15A to 15D The sound level (SPL) (also called modulus or amplitude) and the phase difference between the front sound source and the sound source on each side of the loudspeaker E are shown as a function of the sound frequency. A number of listening directions between 0° and 90° are shown, i.e. distributed in the front hemisphere of the loudspeaker E. Two configurations are shown without and with a waveguide. It can be observed that due to the definition of the positive hole O Slat_av and back hole O Slat_ar The waveguide G, which constitutes the transmitting part, allows better control of the directional lobe.

[0082] In fact, on the amplitude curve, it can be observed that the waveguide allows the sound level to be av The waveguide allows the sound to be distributed more evenly in the front hemisphere of the loudspeaker E.

[0083] Furthermore, on the phase difference curves, it can be observed that waveguide G allows tightening the different curves corresponding to different viewing directions between 0° and 90°, especially for frequencies between 180 Hz and 380 Hz. Due to the use of waveguide G, the scattering is more uniform over a wider frequency band.

[0084] Example 2: DSP solution for backward suppression optimization

[0085] Consider here a symmetrical loudspeaker E with a front low frequency source and low frequency sources on both sides of the loudspeaker. The sound sources are fed by a DSP channel and the amplitude and phase are controlled electronically. This control aims to optimize the suppression behind the loudspeaker. Figures 16A to 16DThe sound level (SPL) (also called modulus or amplitude) is shown as a function of frequency, as well as the phase difference between the frontal sound source and the sound source on each side of the loudspeaker E. Several emission directions between 0° and 180° are represented (i.e. distributed in half space), without distinguishing, due to its symmetry, to the left or right of the loudspeaker E. Two configurations are provided, without and with a waveguide.

[0086] On the amplitude curve it can be observed that the sound level SPL falls off more slowly in the front hemisphere of the loudspeaker (i.e. for listening directions between 0° and 90°) with waveguide G. On the other hand, the narrowing of the curve in directions between 90° and 180° indicates that the waveguide provides better uniformity of suppression in the rear space.

[0087] On the phase difference curve between the front low frequency source and one of the lateral low frequency sources located on one of the sides, it can be observed that the curve related to the coverage cone of the loudspeaker (i.e. between 0° and 50°) tightens up around the axis defining the zero phase difference. This reflects that the loudspeaker E has a better time alignment in the front hemisphere, i.e. on the 0° axis and outside this axis.

[0088] Besides better controlling the directivity of a sound box E comprising at least one waveguide as described above, the use of such a waveguide offers certain advantages in terms of mechanical and assembly performance for products comprising sound sources at the sides.

[0089] The sound box E includes at least one forward sound source S av , at least one lateral sound source S lat and at least one lateral sound source S lat In case of at least one acoustic waveguide G in front and wherein the outer face of the acoustic waveguide G is plane, the loudspeaker E can be stacked with a second loudspeaker E' comprising or not comprising a waveguide G' as described in the present application.

[0090] The lamination may be performed laterally; in this case, the lamination surface is the outer face of the waveguide of the enclosure E and one of the sides of the enclosure E'.

[0091] Each of the speakers E and E' also includes a first upper F Esup and the first one below F Einf On the other hand, it also includes the second upper F E'sup and the second one below F E'inf In the case of , the stacking can be performed from below or from above. Then, the stacking surface is the first top surface F Esup and the second one below F E'inf , or the first F below Einf and the second top F E'sup .

[0092] By stacking enclosures comprising a waveguide G with a flat outer surface from the side and from above or below, enclosures E as described in the present application can form an array of enclosures, some of which can be flipped 180° relative to the others.

[0093] Alternatively, as described in the present application, a handle may be mounted on the outer face of a waveguide G having a flat outer face as described in the present application. In this case, the handle may be designed to be integrated flush with the flat outer face of the waveguide G. Finally, the waveguide G may be designed to be mounted to a speaker E in a manner similar to an external accessory, the speaker having a forward source and a source located on the side facing one or the other side of the speaker E. In this case, the waveguide is mounted to the side F of the speaker E by a mounting device. Elat1 and F Elat2 On any one of .

Claims

1. A sound box (E) having a volume shape having a front face (F Eav )、Back(F Ear )、First side (F Elat1 ) and the second side (E lat2 ) two sides, and the speaker (E) has a front side (F) with the speaker (E) Eav )Vertical main emission direction (D av ) and the back side (F) of the speaker (E) Ear )Vertical back emission direction (D ar ), the sound box (E) comprises: - At least one forward sound source (S av ), which is configured to pass through the front face (F Eav ) emits acoustic streams and has a positive source main emission direction (D Sav ), the main emission direction of the forward source is substantially equal to the main emission direction (D av ); - at least one lateral sound source (S lat ), which faces at least one side with a sound source (F Elat ), the side with the sound source (F Elat ) is the first side (F Elat1 ) and the second side (F Elat2 ) one and / or the other of the two sides, the lateral sound source (S lat ) has a first side surface (F Elat1 ) and the second side (F Elat2 ) and / or another substantially perpendicular lateral source main emission direction (D Slat ); - the forward sound source (S av ) and the lateral sound source (S lat ) are sound sources emitting in substantially the same frequency band; - at least one acoustic waveguide (G), said waveguide (G) being located between said at least one lateral acoustic source (S lat ) in front of the lateral sound source (S lat ) along the main emission direction of the lateral source (D Slat ) The acoustic flow (F lat ), and the acoustic flow (F lat ) is guided to the main emission direction of the lateral source (D Slat ) on both sides of the first plurality of lateral directions (D Slat1 ) and a second plurality of lateral directions (D Slat2 ) in two directions, and the waveguide (G) is assembled to the side (F) having the sound source by an assembly device. Elat ); - At least one positive hole (O Slat_av ), which is formed by the side with the sound source (F Elat ) and the space between the acoustic waveguide (G) so that the acoustic source (S lat ) emitted by the acoustic flow (F lat ) in the direction pointed by the main emission direction (D av ) in the direction of the hemisphere defined by the - at least one back-facing hole (O Slat_ar ), which is formed by the side with the sound source (F Elat ) and the space between the acoustic waveguide (G) so that the lateral sound source (S lat ) emitted by the acoustic flow (F lat ) in the direction of the rear emission of the speaker (D ar ) in the direction of the hemisphere defined by the -Device (G sup , G inf ), which is used to generate a plurality of positive holes (O) in the at least one waveguide (G) except for the at least one positive hole (O Slat_av ) and the at least one back-facing hole (O Slat_ar ) lat ) is blocked to strengthen the sound flow emitted through the forward hole and the back hole and enhance the effect of the cardioid directivity.

2. The speaker (E) according to claim 1, wherein: The at least one forward sound source (S av ) is located in the front volume (V Sav ), and the at least one lateral sound source (S lat ) is located on the side volume (V SLat ), the side volume is connected to the volume (V by at least one partition (C) Sav ) separated by .

3. The speaker (E) according to claim 1, wherein: The forward sound source (S av ) and the lateral sound source (S lat ) Both are sound sources that generally operate in the low-frequency band and / or mid-frequency band.

4. The speaker (E) according to any one of claims 1 to 3, wherein: The forward sound source (S av ) and the lateral sound source (S lat ) is configured to be fed separately by multiple DSP and amplification channels and to be electronically controlled in amplitude and phase so as to control the directivity of the sound radiation of the speaker (E).

5. The speaker (E) according to any one of claims 1 to 4, wherein: The sound box (E) is suitable for being stacked with another sound box (E') according to any one of claims 1 to 4; - wherein each of the speaker (E) and the other speaker (E') further comprises, on one hand, a first upper surface (F Esup ) and the first below (F Einf ), and on the other hand also includes a second upper surface (F E'sup ) and the second below (F E'inf ); - wherein the speaker box (E) is suitable for being stacked with the other speaker box (E') from below, above or side.

6. The sound box (E) according to any one of claims 1 to 5, wherein: The sound box is of bass reflex type and further comprises a sound source (S Lat ) is associated with at least one vent, characterized in that the at least one vent is located on the back side (F) of the speaker (E) Ear ).

7. The sound box (E) according to any one of claims 1 to 6, wherein: The device for shielding the sound flow (G sup , G inf ) on the top (F) of the speaker (E) Esup ) and below (F Einf ) in a flat and continuous manner to form the side with the sound source (F Elat ) is connected to the acoustic waveguide (G).

8. The sound box (E) according to any one of claims 1 to 7, wherein: The device for blocking the sound flow is configured to block the sound flow (Flat) transmitted by the sound wave guide (G) in the following directions: on the one hand, perpendicular to the emission direction in the main emission direction (DSlat) of the lateral source, and on the other hand, perpendicular to the top (Fesup) and the bottom (FEinf), so that the sound flow leaks out only through at least one forward hole (OSlat_av) and at least one rear hole (OSlat_ar).

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