Directional electro-acoustic conversion system and network of electro-acoustic conversion systems including such a system

Abstract

The invention relates to a directional electro-acoustic conversion system (100) comprising an enclosure (10) having walls delimiting an internal volume (104) of the enclosure, a front wall (101) and a first side wall (102a), and at least one first loudspeaker (11a) having a principal emission axis (112a), configured to emit in a frequency range between 30 Hz and 400 Hz, and a second loudspeaker (12a) having a principal emission axis (122a), configured to emit in a frequency range between 30 Hz and 400 Hz, the first loudspeaker (11a) being disposed in the front wall (101) and the second loudspeaker (12a) being disposed in the first side wall (102a), and the emission axis (112a) and the emission axis (122a) forming an angle α between them of -45° and 90°.The invention also relates to a network (900) of electro-acoustic conversion systems comprising at least two directional electro-acoustic conversion systems (100). Figure for the abstract: Fig. 1.

Description

Title of the invention: Directional electroacoustic conversion system and network of electroacoustic conversion systems comprising such a system. Technical field

[0001] The present invention relates to the field of sound diffusion systems.

[0002] It relates more particularly to a directional electro-acoustic conversion system, especially in at least one frequency band between approximately 30 Hz and 400 Hz.

[0003] The present invention finds in particular a direct application in the field of event management, for sound diffusion during concerts, shows and other events in front of a large audience and more particularly in open or semi-open environments. State of the art

[0004] The diffusion of music in large outdoor spaces represents a technical challenge in order to ensure that the sound reproduction of the amplified music is as faithful as possible in the audience area, and that emergences are as low as possible outside this area.

[0005] Electro-acoustic conversion systems were then developed to optimize sound diffusion by seeking in particular to improve the directivity of said systems in two perpendicular planes of propagation of acoustic waves, a first plane, typically vertical with respect to the ground, and a second plane orthogonal to the first, i.e. typically horizontal.

[0006] By way of example, in the vertical plane of sound emission, it is possible to obtain a directional system, that is to say, one offering directivity oriented in a preferred direction, known as cardioid directivity, as opposed to omnidirectional directivity which is identical in all directions, by means of stacking a plurality of acoustic systems, thus forming a vertical column that can reach several meters in height. Such a system is then considered a linear acoustic source, the English term for which is more commonly used: "Line Source Array". Moreover, the systems of the plurality of systems are generally stacked at an open angle, usually small, i.e., a few degrees, vertically producing a constructive pressure field in the principal direction of emission.

[0007] A system is known which includes a vertical set of speakers which can be suspended and which allows in particular the vertical angle between each speaker of the system to be adjusted in order to homogenize the sound level over the depth of the audience area.

[0008] In the vertical plane, this system is directional. On the other hand, in a horizontal transverse plane, the directivity of this system is not satisfactory because below typically 400 Hz, the horizontal directivity of the system widens until it becomes omnidirectional around typically 100 Hz.

[0009] In the horizontal plane, other "cardioid" systems are also used to improve directivity. To achieve good diffusion efficiency in the frequency range below 400 Hz, such a system includes a subwoofer equipped with several loudspeakers positioned at different locations within the subwoofer. Appropriate signal processing on each of the subwoofer's loudspeakers will limit the acoustic power emitted, particularly towards the rear of the subwoofer, and increase the power emitted towards the front, and consequently improve the system's directivity.

[0010] A loudspeaker system is also known, comprising at least one first low-frequency sound source and at least one high-frequency and / or mid-frequency sound source. At least one loudspeaker is located on the side of the enclosure and oriented perpendicularly to the principal radiation direction. This system provides controlled directivity in the horizontal plane for all useful frequencies, including the 30 Hz to 400 Hz band. To achieve controlled directivity over the 30 Hz to 400 Hz band, a low-pass filter is applied to the loudspeaker(s) located on the side of the enclosure so that they do not emit beyond certain frequencies. Without the application of low-pass filters, the loudspeaker(s) located on the sides of the enclosure would emit towards the sides of the system at mid frequencies, and the system's directivity would no longer be controllable.

[0011] Thus, current systems require the use of a multitude of loudspeakers, some of which are used only on a narrow frequency band.

[0012] This raises the question of optimizing the use of this type of system. It may then be advantageous to maximize the ratio between the weight of the enclosure and the sound pressure level, generally designated "SPL" (SPL being the English acronym for Sound Pressure Level), in order to obtain greater emission power, but with the same number of loudspeakers.

[0013] The present invention aims to remedy, at least in part, the aforementioned disadvantages, while also leading to other advantages.

[0014] To this end, the present invention relates to a directional electroacoustic conversion system comprising a box having walls delimiting an internal volume of the box, a first of the walls forming a front wall and a second walls forming a first lateral wall, the enclosure further comprising at least one partition dividing the internal volume of the enclosure into two chambers separated from each other by the partition, the first of the two chambers comprising the front wall of the enclosure, and the second of the two chambers comprising the first lateral wall of said enclosure, the system further comprising: - a first loudspeaker having a main emission axis, called the primary emission axis, and being configured to emit in a frequency range of at least between 30 Hz and 400 Hz; - a second loudspeaker having a main emission axis, called secondary emission axis, and being configured to emit in a frequency range of at least between 30 Hz and 400 Hz; - the first speaker being located in the front wall and the second speaker being located in the first side wall; and - the primary emission axis and the secondary emission axis forming an angle α between them between -45° and 90°.

[0015] The directional electro-acoustic conversion system thus configured and having an angle α between -45° and 90° between the primary emission axis of the first loudspeaker and the secondary emission axis of the second loudspeaker makes it possible to obtain a cardioid type directivity in the frequency range of at least between 30 Hz and 400 Hz.

[0016] The configuration of the enclosure with speakers arranged on different walls allows for better management of the system's directivity, particularly in the low frequencies where directivity is naturally more difficult to control.

[0017] A gain in directivity and / or power is obtained, compared with systems which only use one loudspeaker, or a plurality of loudspeakers arranged in the front wall.

[0018] The separation of the internal volume into two chambers by a partition offers the possibility of treating the sound waves emitted by each loudspeaker differently, which contributes to better control of the overall acoustic response of the system.

[0019] The system thus configured makes it possible to provide sound reinforcement for events taking place in locations near sensitive areas where the ambient noise level is particularly controlled. In these sensitive areas, the noise level must not exceed a relatively low threshold in order to limit potential noise pollution. For example, these sensitive areas include school groups, residential areas, or healthcare facilities (hospitals, nursing homes, etc.).

[0020] According to one feature, the primary emission axis and the secondary emission axis form an angle a of 45°.

[0021] According to another feature, the primary emission axis and the secondary emission axis form an angle a of 0°.

[0022] The choice of the value of angle a depends on the desired effect on directivity and / or on acoustic power by allowing, for example, maximizing phase coherence between loudspeakers or improving the focusing of the sound intensity of the system.

[0023] According to one feature, the enclosure comprises a second side wall, the front wall being located between the first side wall and the second side wall, said enclosure comprising a third loudspeaker disposed in the second side wall, the third loudspeaker being identical to the second loudspeaker.

[0024] The use of a third loudspeaker allows emission at a higher sound level, while maintaining a cardioid type directivity.

[0025] According to another feature, the secondary emission axis of the second loudspeaker and the secondary emission axis of the third loudspeaker form an angle [3iaterai] between 0° and 90°, said angle being convergent.

[0026] The system thus configured makes it possible to concentrate the acoustic intensity on a focal area, thus directing the sound waves into specific environments.

[0027] According to another feature, the secondary emission axis of the second loudspeaker and the secondary emission axis of the third loudspeaker form an angle [3iaterai] between 0° and 90°, said angle being divergent.

[0028] The system thus configured makes it possible to widen the sound coverage in the horizontal plane while maintaining a cardioid type directivity.

[0029] According to one feature, the system includes a fourth speaker which is arranged in the front wall of the enclosure, the fourth speaker being identical to the first speaker.

[0030] The use of a fourth loudspeaker arranged in the front wall increases the acoustic power emitted by the system, without changing the directivity which is still of the cardioid type.

[0031] According to one feature, the primary emission axis of the first loudspeaker and the primary emission axis of the fourth loudspeaker form a squaring angle between 0° and 90°, said angle being convergent.

[0032] According to one feature, the primary emission axis of the first loudspeaker and the primary emission axis of the fourth loudspeaker form a Paving angle between 0° and 90°, said angle being divergent.

[0033] As before, the system thus configured allows, depending on whether the Pavant angle is convergent or divergent, either to concentrate the acoustic intensity on a focal zone, and therefore to direct the sound waves in environments specific, either to widen the sound coverage in the horizontal plane, while maintaining a cardioid type directivity in both cases.

[0034] According to one feature, the system further comprises at least one high-frequency loudspeaker having an emission frequency band of at least between 5 kHz and 20 kHz, and the high-frequency loudspeaker being positioned in the front wall of the enclosure.

[0035] The use of at least one high-frequency loudspeaker makes it possible to emit on a frequency band going beyond the frequency range between 30 Hz and 400 Hz.

[0036] According to another feature, the system further comprises at least one mid-frequency loudspeaker having an emission frequency band of at least between 500 Hz and 2 kHz, and the mid-frequency loudspeaker being positioned in the front wall of the enclosure.

[0037] According to another feature, the high-frequency speaker is positioned between the first speaker and the fourth speaker (11b) and equidistant from said speakers.

[0038] The system thus configured allows a balanced distribution of sound intensity in a frequency range from 30 Hz to 20 kHz.

[0039] Finally, the invention also relates to a network of electroacoustic conversion systems comprising at least two electroacoustic conversion systems, a first of the at least two electroacoustic conversion systems being a directional electroacoustic conversion system having at least some of the preceding characteristics.

[0040] The invention, according to an exemplary embodiment, will be better understood and its advantages will become more apparent upon reading the following detailed description, given by way of example and in no way limiting, with reference to the accompanying drawings in which:

[0041] [Fig.1] [Fig.1] represents a directional electro-acoustic conversion system, according to a first embodiment of the invention, respectively in perspective view (A), front view (B), section view (C);

[0042] [Fig.2] [Fig.2] represents a directional electro-acoustic conversion system, according to a second embodiment of the invention, respectively in perspective view (A), front view (B), section view (C);

[0043] [Fig.3] [Fig.3] represents a directional electro-acoustic conversion system, according to a third embodiment of the invention, respectively in perspective view (A), front view (B), section view (C);

[0044] [Fig.4] [Fig.4] represents a directional electro-acoustic conversion system, according to a fourth embodiment of the invention, respectively in perspective view (A), front view (B), section view (C);

[0045] [Fig.5] [Fig.5] represents a directional electro-acoustic conversion system, according to a fifth embodiment of the invention, respectively in perspective view (A), front view (B), section view (C);

[0046] [Fig.6] [Fig.6] represents a directional electro-acoustic conversion system, according to a sixth embodiment of the invention, respectively in perspective view (A), front view (B), section view (C);

[0047] [Fig. 7] [Fig. 7] represents a perspective view of a network of electro-acoustic conversion systems, according to an embodiment of the present invention; and

[0048] [Fig.8] [Fig.8] represents an example of an isobaric diagram of horizontal directivity of a network comprising twenty electro-acoustic conversion systems according to the third embodiment of the invention.

[0049] Identical elements represented in the aforementioned figures are identified by identical numerical references.

[0050] A “directional” system here means an acoustic system producing acoustic radiation which is maximal along a principal axis of the acoustic system, in other words for an angle of 0°, and for which the acoustic radiation is effective for angles between approximately + / - 65° with respect to said axis.

[0051] The following frequency bands are considered here: - Bass, for a frequency between 20 Hz and 500 Hz; - Average, for a frequency between 500 Hz and 2 kHz; and - High, for a frequency between 2 kHz and 20 kHz.

[0052] This definition of frequency bands is given for guidance purposes only, the limit values ​​may vary, or even overlap.

[0053] In the context of the present invention, the term "convergent" is used to describe an angle formed by the principal axes of sound emission of two loudspeakers which are arranged in a configuration such that their axes of sound emission tend towards a common point or towards a focal area.

[0054] Conversely, the term "divergent" is used to describe an angle formed by the principal axes of sound emission of two loudspeakers which are arranged in a configuration where the axes of sound emission of the two loudspeakers are oriented so that they move away from each other.

[0055] Fig. 1 represents a directional electro-acoustic conversion system 100, according to a first embodiment of the invention.

[0056] In [Fig.1] in (A), a perspective view of the directional electroacoustic conversion system 100 is shown.

[0057] The directional electro-acoustic conversion system 100 comprises a box 10 having a plurality of walls delimiting an internal volume 104, visible on the [Fig.l] in (C). The plurality of walls includes in particular a front wall 101, a first side wall 102a, a second side wall 102b and a rear wall 103.

[0058] In this particular embodiment, the system 100 includes a first loudspeaker 1a and a fourth loudspeaker 11b arranged in the front wall 101 of the box 10. The system 100 also includes a second loudspeaker 12a arranged in the first side wall 102a of the box 10, as well as a third loudspeaker 12b arranged in the second side wall 102b of said box.

[0059] The internal volume 104 is delimited on [Fig.1] in (C) by dotted lines.

[0060] The box 10 further comprises at least one partition 105 dividing the internal volume 104 of said box into two chambers separated from each other by the partition 105. A first chamber 106 comprises the front wall 101 of the box 10, and a second chamber 107 comprises the first side wall 102a as well as, in the present embodiment, the second side wall 102b of said box.

[0061] In an alternative embodiment (not shown here), the second chamber 107 is itself divided into two parts. Thus, the second loudspeaker 12a and the third loudspeaker 12b each have their own rear volume, each of said volumes having at least one vent. This configuration can be applied to all the embodiments described below.

[0062] Each speaker 1a, 11b, 12a and 12b is configured to emit in a frequency range of at least between 30 Hz and 400 Hz.

[0063] In a particular embodiment, speakers 1a and 11b are different from speakers 12a and 12b.

[0064] In addition, for the system 100 to emit in frequency ranges above 400 Hz, said system comprises at least one mid-frequency loudspeaker 13a, 13b, 13c, and 13d, as well as at least one high-frequency loudspeaker 14. In the embodiment shown in [Fig. 1], the system 100 comprises four mid-frequency loudspeakers 13a, 13b, 13c, and 13d and one high-frequency loudspeaker 14 arranged in the front wall 101 of the enclosure 10. The presence of a mid-frequency loudspeaker 13a, 13b, 13c, and 13d is optional. According to one embodiment, the system 100 may be without mid-frequency loudspeakers 13a, 13b, 13c, and 13d. This is the case for the fourth example, the fifth example as well as the sixth example of realization, respectively represented in [Fig.4], [Fig.5] and [Fig.6].

[0065] The first loudspeaker 1a and the fourth loudspeaker 11b each have a principal emission axis, called primary emission axis respectively 112a and 112b.

[0066] The second loudspeaker 12a and the third loudspeaker 12b each have a main emission axis, called secondary emission axes respectively 122a and 122b.

[0067] The primary emission axis 112a of the first loudspeaker 1la and the secondary emission axis 122a of the second loudspeaker 12a form an angle α between them between -45° and 90°. In the example illustrated here, the angle α is approximately 25°.

[0068] Similarly, the primary emission axis 112b of the fourth loudspeaker 11b and the secondary emission axis 122b of the third loudspeaker 12b form an angle between them between -45° and 90°, which is here about 25°.

[0069] In the example illustrated here, the first loudspeaker 1a, the second loudspeaker 12a, the third loudspeaker 12b, and the fourth loudspeaker 11b are mounted in the conventional manner on the enclosure 10, that is, with their diaphragms facing outwards. In other embodiments, all or some of the loudspeakers constituting the system 100 are mounted in a so-called "inverted" configuration, that is, with their diaphragms facing inwards towards the enclosure 10, while their magnets and voice coils are located outside the enclosure. This type of assembly optimizes the internal volume 104 of the enclosure 10, but also generates better heat dissipation from the magnet and the speaker coil, compared to a conventional assembly where the heat is not vented outside the enclosure 10, but remains confined inside the enclosure, or is partially vented through one or more vents.Furthermore, this type of mounting improves the coupling of the system 100 speakers.

[0070] The forward orientation of the second and third loudspeakers 12a and 12b improves the acoustic performance of the system 100. In particular, a frequency range in the low frequencies is more extended than those of the prior art, increasing the power radiated forwards.

[0071] Furthermore, the size of the system 100 is limited due to the orientation of the second and third loudspeakers 12a and 12b, which are oriented "in front" of the box and at the same time convergently.

[0072] This particular orientation generates here an angle |3iateral between the secondary emission axis 122a of the second loudspeaker 12a and the secondary emission axis 122b of the third loudspeaker 12b. The angle [3iateral is between 0° and 90°. In this embodiment, the angle [3iateral is equal to 45° and is convergent.

[0073] Furthermore, the primary emission axis 112a of the first loudspeaker 1la and the primary emission axis 112b of the fourth loudspeaker 11b form an angle [3avant] between 0° and 90°. In this embodiment, the angle [3avant] is equal to 0°, i.e. their emission axes are parallel.

[0074] Furthermore, the system 100 includes at least one vent. In this particular embodiment, the system 100 includes two vents 11a and 11b arranged in the wall before 101 of the box 10, and a vent 121 disposed in the rear wall 103, without this configuration presenting a limitation to the present invention.

[0075] In [Fig.1] in (C), a cross-sectional view of the system 100 along the axis AA illustrated [Fig.1] in (B) is shown.

[0076] Fig. 2 represents the directional electro-acoustic conversion system 100, according to a second embodiment of the invention.

[0077] This embodiment differs from the previous one by the orientation of the second speaker 12a and the third speaker 12b.

[0078] The angle [3iaterai between the secondary emission axis 122a of the second loudspeaker 12a and the secondary emission axis 122b of the third loudspeaker 12b is equal to 0°.

[0079] The angle [3avant between the primary emission axis 112a of the first loudspeaker 1la and the primary emission axis 112b of the fourth loudspeaker 11b is equal to 0°, as in the previous embodiment.

[0080] Fig. 3 represents the directional electro-acoustic conversion system 100, according to a third embodiment of the invention.

[0081] This embodiment differs from the first embodiment by the orientation of the second speaker 12a and the third speaker 12b.

[0082] In this particular embodiment, the angle [3front is equal to 0°, and the angle [3side is equal to 45° and is divergent. Compared with the embodiment shown in [Fig. 1], the second loudspeaker 12a and the third loudspeaker 12b are oriented "in front" of the enclosure 10 and simultaneously divergently, and not oriented "in front" and simultaneously convergently.

[0083] Fig. 4 represents the directional electro-acoustic conversion system 100, according to a fourth embodiment of the invention.

[0084] This embodiment differs from the first embodiment by the orientation of the second speaker 12a and the third speaker 12b, as well as by the orientation of the first speaker 1a and the fourth speaker 11b.

[0085] In this particular embodiment, the angle [3front is equal to 90°, and the angle [3side is equal to 0° and is convergent. Thus, the first loudspeaker 1a and the fourth loudspeaker 11b are oriented "in front" of the enclosure 10 and at the same time convergently.

[0086] This configuration has the particular advantage of having a reduced footprint, for example compared to the 100 system shown in [Fig.2], while having a cardioid type directivity in the frequency band from 30 Hz to 400 Hz, in particular.

[0087] In another embodiment not shown here, the high-frequency speakers 14 are replaced by at least one mid-frequency speaker 13a, 13b, 13c and 13d, while maintaining the same architecture of system 100, all other things being equal. The same applies to the embodiment presented in [Fig. 5].

[0088] Figure 5 represents a directional electro-acoustic conversion system 100, according to a fifth embodiment of the invention. This fifth embodiment is a combination of the electro-acoustic conversion systems shown in Figure 1 and Figure 4.

[0089] This fifth embodiment differs from the first embodiment by the orientation of the first speaker 1a and the fourth speaker 11b, and differs from the fourth embodiment by the orientation of the second speaker 12a and the third speaker 12b.

[0090] In this particular embodiment, the angle [3avant] is equal to 90°, which is convergent, and the angle |3iaterai is equal to 90°, which is also convergent. Thus, the first loudspeaker 1a and the fourth loudspeaker 11b are oriented "in front" of the enclosure and simultaneously convergently. The same is true for the second loudspeaker 12a and the third loudspeaker 12b, which are oriented "in front" of the enclosure 10 and simultaneously convergently.

[0091] Compared with the electroacoustic conversion system configurations presented previously, this configuration is even more compact while having a cardioid type directivity in the frequency band from 30 Hz to 400 Hz, in particular.

[0092] Fig. 6 represents the directional electro-acoustic conversion system 100, according to a sixth embodiment of the invention.

[0093] This embodiment differs from the first embodiment in that said system does not include a fourth speaker 11b, nor mid-frequency speakers 13a, 13b, 13c and 13d, nor high-frequency speakers 14.

[0094] In this particular embodiment, the angle [3iaterai] is approximately 55° and is convergent. Thus, the second loudspeaker 12a and the third loudspeaker 12b are oriented "in front" of the enclosure 10 and at the same time convergently.

[0095] Compared to the electroacoustic conversion system configurations presented previously, this configuration is even more compact while maintaining cardioid directivity in the frequency band from 30 Hz to 400 Hz, in particular. Thus, for similar loudspeakers, using three low-frequency drivers instead of four reduces the system mass by 100.

[0096] In yet another embodiment not shown here, the system comprises two low-frequency loudspeakers. Based on the embodiment of [Fig. 6], the first loudspeaker 1a is then arranged in the front wall 101 of the enclosure 10, and the second loudspeaker 12a is arranged in the first side wall 102a of the box 10. Compared to the embodiment of [Fig.6], this embodiment with two low-frequency speakers makes it possible to further reduce the size of the electro-acoustic conversion system, while maintaining a cardioid type directivity in the frequency band from 30 Hz to 400 Hz, in particular.

[0097] The electro-acoustic conversion systems described above allow control of the directivity over the entire useful frequency range of said systems, i.e. from 30 Hz to 20 kHz.

[0098] Fig. 7 represents a perspective view of a 900 network of electro-acoustic conversion systems comprising at least two electro-acoustic conversion systems.

[0099] According to the present embodiment, at least one of the at least two electro-acoustic conversion systems is a directional electro-acoustic conversion system 100 according to any one of the embodiments described with reference to Figures 1 to 6.

[0100] In particular here, all the systems of the 900 network are identical.

[0101] In the particular embodiment shown in [Fig. 7], the 900 network comprises nine systems 100a, 100b, 100c, lOOd, 100e, lOOf, 100g, lOOh and lOOi without this being a limitation to the present invention.

[0102] The systems 100a, 100b, 100c, lOOd, 100e, lOOf, 100g, lOOh and lOOi are assembled together, one after the other, vertically and by means of a fastening device not shown here. Two consecutive systems 100a, 100b, 100c, lOOd, 100e, lOOf, 100g, lOOh and lOOi respectively form a pair 19a, 19b, 19c, 19d, 19e, 19f, 19g and 19h. Within each pair 19a, 19b, 19c, 19d, 19e, 19f, 19g and 19h, the systems 100a, 100b, 100c, lOOd, 100e, lOOf, 100g, lOOh and lOOi are arranged according to an angle of inclination specific to said pairs.

[0103] The 900 network makes it possible to obtain a cardioid type directivity over the frequency band from 30 Hz to 20000 Hz, both in the horizontal plane and in the vertical plane.

[0104] [Fig.8] represents an example of an isobaric diagram of the horizontal directivity of a network similar to the network 900 of [Fig.7], comprising twenty electro-acoustic conversion systems 100 according to the third embodiment of the invention shown in [Fig.3].

[0105] The diagram represents a sound pressure level 81 expressed according to a scale in decibels and in grey level, as a function of a frequency axis 82 on the abscissa and an angle axis 83 on the ordinate.

[0106] To obtain the desired cardioid directivity over the frequency band from 30 Hz to 400 Hz, the loudspeakers 11a, 11b, 12a and 12b are amplitude controlled as follows than in phase by means of passive and / or active filters allowing the signal to be processed before it is emitted.

[0107] On the diagram, three zones 89a, 89b and 89c extending respectively from 30 Hz to 80 Hz, from 80 Hz to 270 Hz, and from 270 Hz to 2000 Hz are represented by being delimited by frames in dotted lines.

[0108] A first zone 89a of the three zones corresponds to a frequency band where the 900 network has an effective directivity between + / -75° with respect to a main emission axis of the 900 network of electro-acoustic conversion systems taken as an example.

[0109] A second zone 89b of the three zones corresponds to a frequency band where the 900 network has an effective directivity which decreases from + / - 75°, at about 100 Hz, to + / - 35°, at about 270 Hz.

[0110] Finally, a third zone 89c of the three zones corresponds to a frequency band where the 900 network has an effective directivity of approximately + / - 35°. The directivity can be considered constant from 270 Hz and over the rest of the audible frequency band (the diagram only goes up to 2000 Hz for readability).

[0111] It is also noted that over the frequency band from 30 Hz to 400 Hz, the sound pressure level is low, or even negligible towards the rear of the 900 network, said level being less than or equal to -12 dB beyond an angle of + / - 90°.

Claims

Demands

1. A directional electro-acoustic conversion system (100) comprising an enclosure (10) having walls delimiting an internal volume (104) of the enclosure, a first wall forming a front wall (101) and a second wall forming a first side wall (102a), the enclosure further comprising at least one partition (105) dividing the internal volume (104) of the enclosure into two chambers separated from each other by the partition (105), a first of the two chambers (106) comprising the front wall (101) of the enclosure (10), and a second of the two chambers (107) comprising the first side wall (102a) of said enclosure, the system (100) further comprising at least one first loudspeaker (1a) having a principal emission axis, referred to as the primary emission axis (112a), and being configured to emit in a frequency range of at least between 30 Hz and 400 Hz, and a second loudspeaker (12a) having a principal emission axis,said secondary emission axis (122a), and being configured to emit in a frequency range of at least between 30 Hz and 400 Hz, the first loudspeaker (11a) being disposed in the front wall (101) and the second loudspeaker (12a) being disposed in the first side wall (102a), and the primary emission axis (112a) and the secondary emission axis (122a) forming between them an angle α of between -45° and 90°.

2. System (100) according to claim 1, characterized in that the primary emission axis (112a) and the secondary emission axis (122a) form an angle a of 45°.

3. System (100) according to claim 1, characterized in that the primary emission axis (112a) and the secondary emission axis (122a) form an angle a of 0°.

4. System (100) according to any one of claims 1 to 3, characterized in that the enclosure (10) comprises a second side wall (102b), the front wall (101) being located between the first side wall (102a) and the second side wall (102b), and in that it comprises a third loudspeaker (12b), the third loudspeaker (12b) being arranged in the second side wall (102b), the third loudspeaker (12b) being identical to the second loudspeaker (12a).

5. System (100) according to claim 4, characterized in that the secondary emission axis (122a) of the second loudspeaker (12a) and the secondary emission axis (122b) of the third loudspeaker (12b) form an angle [3iaterai] between 0° and 90°, said angle being either convergent or divergent.

6. System (100) according to any one of claims 1 to 5, characterized in that it comprises a fourth loudspeaker (11b), the fourth loudspeaker (11b) being disposed in the front wall (101) of the enclosure (10), and the fourth loudspeaker (11b) being identical to the first loudspeaker (1a).

7. System (100) according to claim 6, characterized in that the primary emission axis (112a) of the first loudspeaker (11a) and the primary emission axis (112b) of the fourth loudspeaker (11b) form an angle [3avant] between 0° and 90°, said angle being either convergent or divergent.

8. System (100) according to any one of the preceding claims, characterized in that it further comprises at least one high-frequency loudspeaker (14) having an emission frequency band of at least between 5 kHz and 20 kHz, and the high-frequency loudspeaker (14) being positioned in the front wall (101) of the enclosure.

9. System (100) according to claims 6 and 8, characterized in that the high-frequency loudspeaker (14) is positioned between the first loudspeaker (1a) and the fourth loudspeaker (11b) and equidistant from each of said loudspeakers.

10. Network (900) of electro-acoustic conversion systems comprising at least two electro-acoustic conversion systems, characterized in that at least a first of the at least two electro-acoustic conversion systems is a directional electro-acoustic conversion system (100) according to any one of claims 1 to 9.

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