SPEAKER CONFIGURED TO GENERATE SOUND WITH LOW SPATIAL DECAY AND NO RESONANCE EFFECT IN A REVERBERANT ENVIRONMENT

Abstract

------ Enclosure configured to generate sound with low spatial decay and without resonance effect in a reverberant medium The invention relates to an enclosure (1), comprising: a front face (2); a rear face (3); a casing (4) connecting the front face (2) to the rear face (3); at least one electromagnetic actuator (6) mechanically connected to the front face (2) and configured to generate vibrations in the front face (2) from a control signal; at least one solid core (7), extending between the front face (2) and the rear face (3), such that the or each core (7) transmits vibrations between the front face (2) and the rear face (3); and control electronics configured to deliver control signals to the electromagnetic actuator (6) or to each electromagnetic actuator (6) so as to generate a sound by vibrating the front face (2), the at least one core (7), the casing (4) and the rear face (3).Figure to be published: Figure 4.

Description

Title of the invention: SPEAKER CONFIGURED TO GENERATE SOUND WITH LOW SPATIAL DECAY AND WITHOUT RESONANCE EFFECT IN A RE MEDIUM VERBERANT

[0001] The present invention relates to the technical field of acoustic speakers, and more particularly relates to a speaker configured to generate a sound with low spatial decay and without resonance effect in a reverberant medium.

[0002] There are already acoustic speakers inspired by violin-making techniques, which use a wooden panel vibrated by mechanical electromagnetic transducers to generate sound. Speakers of this type are generally intended to be fixed to a wall. Patent applications WO2008107853A1 and EP1734786A2, for example, present acoustic speakers of this type.

[0003] These existing loudspeakers, however, have several drawbacks. First of all, they require a large panel, which makes them bulky and heavy. Furthermore, as with loudspeakers with "conventional" speakers, the sound generated has a noticeable spatial decay and creates resonance in a reverberant environment, which harms the listening experience of users. These nuisances are even more marked for a user suffering from a hearing impairment.

[0004] Therefore, the prior art solutions proposed for loudspeakers still have drawbacks and improvements are possible.

[0005] The present invention aims in particular to solve the problems indicated above by proposing a speaker configured to generate a sound with low spatial decay and without resonance effect in a reverberant medium.

[0006] Thus, the present invention relates to an enclosure configured to generate a sound with low spatial decay and without resonance effect in a reverberant medium, characterized in that the enclosure comprises: a front face; a rear face, arranged opposite the front face; an envelope, having an average density greater than or equal to an average density of the front face and to an average density of the rear face, connecting the front face to the rear face and enclosing an interior space defined between the front face and the rear face; at least one electromagnetic actuator, the or each electromagnetic actuator being arranged in the interior space and mechanically connected to a surface of the front face facing the rear face and being configured to generate vibrations in the front face from a control signal; at least one solid core, the or each core having an average density less than or equal to the average density of the front face and the average density of the rear face, the or each core extending between the front face and the rear face and having a first end force-fitted in a recess formed in the front face and a second end, opposite the first end, force-fitted in a recess formed in the rear face, such that the or each core transmits vibrations between the front face and the rear face; and control electronics configured to deliver control signals to the or each electromagnetic actuator so as to generate a sound by vibrating the front face, the at least one core, the casing and the rear face.

[0007] This speaker configuration makes it possible to generate a sound with low spatial decay and without resonance effect in a reverberant environment.

[0008] In particular, the applicant has discovered that an assembly of the front face, the rear face, the envelope and the cores according to the invention makes it possible to use the entire enclosure and the interior space to generate sound, which makes it possible to significantly reduce the spatial decay of the sound generated by the enclosure and also makes it possible to limit resonance, even in reverberant places.

[0009] According to a particular embodiment, the enclosure further comprises at least one solid secondary core, the or each secondary core having an average density less than or equal to the average density of the envelope, the or each secondary core extending between a part of the envelope and another part of the envelope located opposite, and the or each secondary core having a first end force-fitted in a recess formed in the envelope and a second end, opposite the first end, force-fitted in another recess formed in the envelope, such that the or each secondary core transmits vibrations between two corresponding parts of the envelope.

[0010] The applicant has discovered that the use of secondary cores makes it possible to accentuate the medium frequencies and to improve the intelligibility of the sound generated by the speaker, in particular for people suffering from hearing impairment.

[0011] According to a particular embodiment, the enclosure further comprises a reinforcing member arranged on the surface of the front face facing the rear face, at angles between the front face and the envelope, said reinforcing member being connected to both the front face and the envelope, and said reinforcing member having an average density greater than or equal to the average density of the envelope.

[0012] This configuration is preferred when the electromagnetic actuators are directly fixed to the front face. The reinforcing member is fixed to both the front face and the casing, preferably by screwing, so as to reinforce the connection between the front face and the casing. The reinforcing member has the effect of promoting a transfer of vibrations between the front face and the casing. The reinforcing member can, for example, be formed by cleats screwed to the front face and the casing.

[0013] According to a particular embodiment, the enclosure further comprises at least one soundboard fixed to the front face in the interior space, the or each soundboard having an average density less than or equal to the average density of the front face, the or each soundboard comprising a first contact surface configured to be brought into contact with the surface of the front face facing the rear face, and a second contact surface, opposite the first contact surface of said soundboard, configured to receive at least one electromagnetic actuator, such that the or each soundboard forms an interface between the front face and the at least one electromagnetic actuator, such that vibrations are generated in the soundboard by the at least one electromagnetic actuator and then generated in the front face.

[0014] It will be understood that the soundboards serve as interfaces to better control the vibration of the front face. It will also be understood that the shape of the soundboards makes it possible in particular to control a mode of generation and propagation of vibrations in the front face, and also makes it possible to work on the range of wavelengths restored.

[0015] According to a particular embodiment, at least one core has its first end force-fitted both in the respective recess formed in the front face and in a through opening formed in a soundboard, so as to pass through said soundboard, the enclosure being configured such that the or each core passing through a soundboard has an average density less than or equal to the average density of the respective soundboard through which it passes.

[0016] The applicant has discovered that the use of cores which pass through a soundboard makes it possible to work on a wide range of frequencies from low frequencies to high frequencies, including medium or midrange frequencies, which promotes high quality or high resolution sound reproduction. Furthermore, the applicant has also discovered that the use of cores which do not pass through a soundboard makes it possible to work on a more reduced range of frequencies, centered on medium or midrange frequencies, such that the resolution of the sound generated is lower but on the other hand allows better intelligibility, in particular for people suffering from hearing impairment.

[0017] It will be understood that it is possible to combine in the same enclosure cores passing through a soundboard and cores not passing through a soundboard, for example to play on the frequency range reproduced by the enclosure. In particular, it may be advantageous to combine the use of secondary cores and the use of souls connecting the front face to the back face without crossing a soundboard, soundboards being used or not and souls passing through a soundboard being used or not.

[0018] According to a particular embodiment, at least one soundboard has a first contact surface in the shape of an “egg” having three marked roundings.

[0019] It will be understood that an “egg” shape, or an oval shape, allows an ovoid propagation of the vibrations in the front face.

[0020] The applicant has discovered that an ovoid propagation of vibrations in the front face makes it possible to reduce energy dissipation and thus to significantly reduce the spatial decay of the generated sound.

[0021] According to a particular embodiment, for said at least one soundboard having a first contact surface in the shape of an “egg”, a core is mounted on one tip side of the egg and an electromagnetic actuator is fixed on a side opposite the tip of the egg.

[0022] According to a particular embodiment, at least one soundboard has a first contact surface in the shape of an “L”.

[0023] According to a particular embodiment, for said at least one soundboard having a first contact surface in the shape of an “L”, one of the following configurations is respected: a core is mounted at the distal end of one of the crosspiece and the shaft of the “L”, and an electromagnetic actuator is fixed to the distal end of the other of the crosspiece and the shaft of the “L”; and a core is mounted at the intersection of the crosspiece and the shaft of the “L”, a first electromagnetic actuator is fixed to the distal end of the crosspiece of the “L”, and a second electromagnetic actuator is fixed to the distal end of the shaft of the “L”.

[0024] The applicant has notably discovered that the use of an “L” shaped soundboard makes it possible to combine in series two less powerful electromagnetic actuators, while maintaining an efficiency, in terms of generation and transfer of vibrations in the front face, close to that of an “egg” shaped soundboard receiving a single more powerful electromagnetic actuator.

[0025] According to a particular embodiment, at least one core is cylindrical in shape.

[0026] It will be understood that a cylindrical shape makes it possible in particular to facilitate the manufacture of the cores and to facilitate the force-fitting of the cores.

[0027] According to a particular embodiment, the front face and the rear face are flat.

[0028] According to a particular embodiment, the front face and the rear face are pa rally.

[0029] According to a particular embodiment, the envelope comprises two lateral faces, an upper face and a lower face, such that the front face, the envelope and the rear face define a straight block.

[0030] According to a particular embodiment, the front face, where appropriate the reinforcing member, the casing and the rear face are assembled by screwing.

[0031] A screw assembly is particularly advantageous for the transfer of vibrations between the elements of the enclosure. It will be understood, however, that according to variants, the front face, the rear face and the casing can be assembled by other means, for example by gluing, by nailing, by a form-fitting assembly, for example by a dovetail assembly or by a mortise and tenon assembly.

[0032] According to a particular embodiment, at least one soundboard is fixed to the front face by a plurality of screws and at least one electromagnetic actuator is fixed to said at least one soundboard by screwing.

[0033] A screw assembly ensures good anchoring of the soundboards to the front face and good transfer of vibrations between the soundboards and the front face. In addition, a screw assembly allows the speaker to be tuned, in particular by adjusting the positioning of the screws on the soundboards.

[0034] Preferably, the screws used are non-magnetic and of small diameter.

[0035] According to a particular embodiment, screws of the plurality of screws have at least two different lengths.

[0036] The use of screws of different lengths makes it possible to locally anchor a soundboard at a specific distance in the thickness of the front face. By varying the length of the screws used, it is notably possible to tune the speaker more finely.

[0037] According to a particular embodiment, said at least one soundboard fixed to the front face by a plurality of screws comprises a plurality of pre-drilled holes configured to receive screws according to different configurations for fixing to the front face, in order to allow tuning of the enclosure according to thicknesses and materials of the at least one soundboard, the front face, the at least one core, the casing and the rear face.

[0038] The use of pre-drilled soundboards allows in particular the manufacture of “standardized” soundboards, and thus facilitates manufacture and reduces the associated costs.

[0039] According to a particular embodiment, a thickness of the rear face is greater than or equal to a thickness of the front face.

[0040] The applicant has discovered that for an enclosure for which the front face, the rear face and the casing are made of the same material, it is advantageous for the front face to be less thick than the rear face and the casing, which in particular facilitates vibration of the front face using electromagnetic actuators and reduces the associated energy dispersion. Preferably, the casing and the back side have the same thickness.

[0041] According to a particular embodiment, at least one of the front face, of the at least one core, of the envelope, of the rear face, where appropriate of the at least one soundboard, where appropriate of the reinforcing member, and where appropriate of the at least one secondary core is composed of a material chosen from: solid wood, a medium density fiberboard, or MDF, and expanded polyvinyl chloride, or expanded PVC.

[0042] According to a particular embodiment, the front face, the rear face, the envelope and, where appropriate, the reinforcing member have an average density of between 500 and 750 kg / m3, preferably 650 kg / m3, that, where appropriate, the or each soundboard has an average density of between 400 and 600 kg / m3, preferably 500 kg / m3, and that the or each core, and where appropriate the or each secondary core, has an average density of between 275 and 475 kg / m3, preferably between 350 and 400 kg / m3.

[0043] Preferably, the front face, the rear face and the envelope are made of the same material.

[0044] According to a particular embodiment, the rear face further comprises a through opening configured to receive a loudspeaker, preferably a subwoofer, or subwoofer, controlled by the control electronics.

[0045] A subwoofer makes it possible to obtain extreme bass frequencies, which are difficult to obtain solely by vibration of the enclosure induced by electromagnetic actuators.

[0046] It can be specified here that the wavelengths that can be obtained by the enclosure using the electromagnetic actuators depend directly on the dimensions of the front face. The use of a loudspeaker therefore makes it possible to obtain low frequencies, without requiring the use of a large front face, which therefore makes it possible to obtain a more compact enclosure for the same range of restored wavelengths.

[0047] Furthermore, it is known that the efficiency of loudspeakers is low, in particular for subwoofer loudspeakers, and that the majority of the electrical energy consumed is transformed into heat. The applicant has discovered that the use of cores according to the invention makes it possible to reduce dissipation and improve the efficiency of the loudspeaker received in the rear face, which makes it possible to reduce the environmental footprint linked to the use of a speaker according to the invention, and to extend the autonomy of the speaker in the case of a portable speaker.

[0048] According to variants of the invention, the front face and the casing could also comprise through openings configured to receive loudspeakers, in addition to or replacing the loudspeaker received in the rear face.

[0049] According to a particular embodiment, the rear face comprises a vent.

[0050] The vent is for example in the form of a cardboard or PVC tube, of the bass-reflex speaker type.

[0051] According to a particular embodiment, the speaker is of the portable type and comprises a battery configured to power the speaker.

[0052] Particular embodiments of the present invention will now be described, with reference to the accompanying drawings.

[0053] In these drawings:

[0054] [Fig. 1] is a front perspective view of an enclosure according to a first embodiment of the invention, the control buttons and the cladding are not mounted.

[0055] [Fig.2] is a rear perspective view of the enclosure of [Fig.l] showing The interior of the enclosure, the rear panel, the cores, the control electronics, the battery, the control buttons and the casing are not mounted.

[0056] [Fig.3] is a partial rear perspective view of the enclosure of [Fig.l], the loudspeaker speaker and trim are not fitted.

[0057] [Fig.4] is a sectional view of the enclosure of [Fig.l], at the level of a core.

[0058] [Fig.5] is a front view of the rear face of the enclosure of [Fig.l].

[0059] [Fig.6] is a rear view of an enclosure according to the first embodiment of the invention, the casing is partially disassembled and rolled up to present the loudspeaker and the vent.

[0060] [Fig.7] is a schematic representation of the decay measurement positions spatial of a sound generated by a speaker according to the first embodiment of the invention.

[0061] [Fig.8a] is a front view of an “L” shaped soundboard, with posi operation of an electromagnetic actuator and a core, according to a variant of the first embodiment of the invention.

[0062] [Fig.8b] is a front view of an “L” shaped soundboard, with posi operation of two electromagnetic actuators and a core, according to another variant of the first embodiment of the invention.

[0063] If we first refer to [Fig.l], we can see that there is shown an enclosure 1 according to the first embodiment of the invention, comprising a front face 2, a rear face 3 and an envelope 4.

[0064] The front face 2 and the rear face 3 are spaced apart and arranged opposite each other. The casing 4 connects the front face 2 to the rear face 3 by enclosing an interior space 5 defined between the front face 2 and the rear face 3.

[0065] According to the embodiment shown in [Fig.l], the front face 2 and the rear face 3 are flat and arranged parallel to each other. In addition, the envelope 4 comprises two lateral faces, flat and arranged parallel to each other, and a upper face and a lower face, flat and arranged parallel to each other. The enclosure 1 thus has the shape of a straight block defined jointly by the front face 2, the rear face 3 and the envelope 4.

[0066] It will be understood, however, that alternatively the enclosure 1 may have other shapes, for example, the front and rear faces 2, 3 may have a polygonal or round shape, such that the enclosure 1 has the shape of a prism with a polygonal base or a cylinder, respectively. The front and rear faces 2, 3 could also have an oval or irregular shape and the envelope 4 would then be formed in correspondence.

[0067] Furthermore, although according to the embodiment shown in [Fig. 1], the front and rear faces 2, 3 are flat and arranged in parallel, it will be understood that the front and rear faces 2, 3 could be inclined towards each other or have a three-dimensional shape, such that the front and rear faces 2, 3 locally converge or move away from each other locally, for example convex or concave shapes, or a “lightning bolt” shape in cross-section, the rear face 3 could also be a translation of the front face 2.

[0068] Furthermore, as shown in [Fig.l], the front face 2, the rear face 3 and the different faces of the casing 4 are assembled together by screwing. Although a screwed assembly is particularly advantageous for the transfer of vibrations, it will however be understood that according to variants, the front face 2, the rear face 3 and the casing 4 can be assembled by other means, for example by gluing, by nailing, by a form-fitting assembly, for example by a dovetail assembly or by a mortise and tenon assembly.

[0069] If we now also refer to Figures 2 to 4, we can see that the enclosure 1 according to the first embodiment further comprises two electromagnetic actuators 6 and two cores 7. It will be understood that, according to variants, the number of electromagnetic actuators 6 and the number of cores 7 may vary, in particular depending on the size or shape of the enclosure 1 and may possibly be different from each other, the enclosure 1 according to the invention comprising at least one electromagnetic actuator 6 and one core 7.

[0070] Each electromagnetic actuator 6 is arranged in the interior space 5, is mechanically connected to a surface 21 of the front face 2 facing the rear face 3 and is configured to generate vibrations in the front face 2 from a control signal. An electromagnetic actuator 6 may for example be a transducer, for example an electromagnet.

[0071] Each core 7 is a solid element, preferably a cylinder or a bar, which extends longitudinally between the front face 2 and the rear face 3. Each core 7 has a first end force-mounted in a recess 22 formed in the front face 2 and a second end, opposite the first end, force-mounted in a recess 31 formed in the rear face 3, such that each core 7 transmits vibrations between the front face 2 and the rear face 3.

[0072] According to the embodiment shown in Figures 1 to 4, the recesses 22, 31 are in the form of through openings, passing respectively right through the front face 2 and the rear face 3. The use of through openings allows in particular a transfer of vibrations throughout the entire thickness of the front face 2 and the entire thickness of the rear face 3. However, as a variant, the recesses 22, 31 could also be blind holes. According to another non-preferred variant, the cores 7 could also be connected to the front face 2 or to the rear face 3 by means of a connecting element in which the respective end of the core 7 is force-fitted, said connecting element being mechanically connected to the front face 2 or to the rear face 3, for example by screwing, nailing or gluing.

[0073] The applicant has discovered that an assembly of the front face 2, the rear face 3, the casing 4 and the cores 7 according to the invention makes it possible to use the entire enclosure 1 and the interior space 5 to generate sound, which makes it possible to significantly reduce the spatial decay of the sound generated by the enclosure 1 and also makes it possible to limit resonance, even in reverberant places. Measurements of spatial decay, under different conditions and with comparison with a “conventional” enclosure, will be presented below.

[0074] The enclosure 1 also comprises control electronics (not shown) and, preferably, also comprises control buttons (not shown), preferably received in a through opening 41 formed in the casing 4. The control buttons can also, as a variant, be received by the rear face 3.

[0075] It will be understood that the control electronics is configured to generate the control signals intended for the electromagnetic actuators 6, and that the control buttons are configured to allow a user to control the control electronics. It will also be understood that, preferably, the control electronics can also be controlled wirelessly, for example by Bluetooth or by Wifi, for example using a smartphone or a tablet. It will also be understood that musical data can be transmitted to the speaker wired or wirelessly, and that the speaker can comprise a memory configured to store musical data. These elements are already known and will not be described in detail here.

[0076] The enclosure 1 may be of the fixed type, powered by a cable connected to the electrical network, but is preferably of the portable type and further comprises a battery (not shown), preferably a 12 V battery, configured to provide the electrical energy necessary for the operation of the enclosure 1.

[0077] According to the invention, a sound is generated by the speaker 1 by exciting the actuators electromagnetic 6 which set the front face 2 into vibration, and by a transfer of vibrations between the front face 2 and the rear face 3 via the cores 7 and the casing 4.

[0078] Preferably, and as can be seen in Figures 2 to 4, the enclosure further comprises soundboards 8 which form an interface between the front face 2 and the electromagnetic actuators 6. The electromagnetic actuators 6 are preferably connected to the soundboards 8 by screwing. According to non-preferred variants, the electromagnetic actuators 6 could be fixed in another way, for example by nailing or by gluing.

[0079] The soundboards 8 are fixed to the front face 2 in the interior space 5, preferably by a plurality of screws as will be described in more detail below. A screw assembly makes it possible to ensure good anchoring of the soundboards 8 to the front face 2 and good transfer of vibrations between the soundboards 8 and the front face 2. In addition, a screw assembly makes it possible to tune the speaker 1, in particular by varying the positioning of the screws on the soundboards 8 and the length of the screws used. Preferably, the screws used are non-magnetic, of small diameter and have different lengths, so as to locally anchor a soundboard 8 at a specific distance in the thickness of the front face 2.

[0080] Preferably, each soundboard 8 comprises a plurality of pre-drilled holes configured to receive screws according to different attachment configurations to the front face 2, which in particular allows tuning of the enclosure according to thicknesses and materials of the soundboard 8, the front face 2, the cores 7, the casing 4 and the rear face 3, while allowing the manufacture of “standardized” soundboards 8, and thus facilitating manufacture and reducing the associated costs.

[0081] Each soundboard 8 comprises a first contact surface 81 configured to be brought into contact with the surface 21 of the front face 2 facing the rear face 3, and a second contact surface 82, opposite the first contact surface 81, configured to receive an electromagnetic actuator 6, such that each soundboard 8 forms an interface between the front face 2 and the electromagnetic actuator 6, such that vibrations are first generated in the soundboard 8 by the electromagnetic actuator 6 and then are generated in the front face 2.

[0082] It will be understood that the shape of the soundboards 8 makes it possible in particular to control a mode of generation and propagation of vibrations in the front face 2.

[0083] According to the embodiment shown in Figures 2 and 3, each soundboard 8 has a first contact surface 81 in the shape of an “egg”, having three marked roundings. According to a variant, the soundboards 8 can also have an oval shape having a single axis of symmetry. It will be understood that a shape of “egg”, or an oval shape, allows an ovoid propagation of vibrations in the front face 2.

[0084] The applicant has discovered that an ovoid propagation of the vibrations in the front face 2 makes it possible to reduce energy dissipation and thus to significantly reduce the spatial decay of the generated sound.

[0085] The shape of the soundboards 8 also makes it possible to work on the range of wavelengths restored.

[0086] According to variants shown in Figures 8a and 8b, the soundboards 8 have a first contact surface 81 in the shape of an “L”.

[0087] Furthermore, the soundboards 8 shown in Figures 2 to 4, 8a and 8b are flat, such that the first contact surface 81 comes into perfect contact with the front face 2, which is also flat. However, as mentioned above, according to variants, the front face 2 may not be flat. It will then be understood that the first contact surface 81 is formed in a manner complementary to the surface 21 of the front face 2 facing the rear face 3, so as to allow good contact and transfer of vibrations between them.

[0088] Furthermore, the second contact surfaces 82 of the soundboards 8 are preferably flat at least in the regions receiving electromagnetic actuators 6, so as to ensure perfect contact between the second contact surfaces 82 and the electromagnetic actuators 6.

[0089] It will also be understood that, according to variants, the same soundboard 8 can receive several electromagnetic actuators 6. [Fig.8b] represents for example a variant for which a soundboard receives two electromagnetic actuators 6.

[0090] According to the embodiment shown in Figures 2 to 4, the enclosure 1 comprises as many cores 7 as soundboards 8, and each core 7 passes through a respective soundboard 8. In particular, each core 7 has its first end force-fitted both in the respective recess 22 formed in the front face 2 and in a through opening 83 formed in the respective soundboard 8, so as to pass through said soundboard 8. In addition, each soundboard 8 has a first contact surface 81 in the shape of an “egg” and a core 7 is mounted on a tip side of the egg and an electromagnetic actuator 6 is fixed on a side opposite the tip of the egg.

[0091] For the variants shown in Figures 8a and 8b, the soundboard 8 has a first contact surface 81 in the shape of an “L” and one web 7 is provided per soundboard 8. For the variant shown in [Fig.8a], the web 7 is mounted at the distal end of one of the crosspiece and the shaft of the “L”, and an electromagnetic actuator 6 is attached to the distal end of the other of the crosspiece and the shaft of the “L”. For the variant shown in [Fig.8b], the core 7 is mounted at the intersection of the crosspiece and the barrel of the “L”, a first electromagnetic actuator 6 is fixed to the distal end of the crosspiece of the “L”, and a second electromagnetic actuator 6 is fixed to the distal end of the barrel of the “L”.

[0092] Thus, the use of “L”-shaped soundboards 8 is particularly advantageous for allowing the attachment of several electromagnetic actuators 6 to a single soundboard 6.

[0093] The applicant has notably discovered that the use of a soundboard 8 such as represented in [Fig.8b] makes it possible to combine in series two less powerful electromagnetic actuators 6, while retaining an efficiency, of generation and transfer of vibrations in the front face 2, close to that of a soundboard 8 represented in Figures 2 to 4 receiving a single more powerful electromagnetic actuator 6.

[0094] Furthermore, it will be understood that the number of cores 7 may be different from the number of soundboards 8. It will also be understood that, as a variant, several cores 7 may pass through the same soundboard 7 or that certain cores 7 may be mounted between the front face 2 and the rear face 3 at a distance from a soundboard, that is to say without passing through a soundboard 8.

[0095] In particular, the applicant has discovered that the use of cores 7 which pass through a soundboard 8 makes it possible to work on a wide range of frequencies going from low frequencies to high frequencies, passing through the medium or midrange frequencies, which promotes high quality or high resolution sound reproduction. Furthermore, the applicant has also discovered that the use of cores 7 which do not pass through a soundboard 8 makes it possible to work on a more reduced range of frequencies, centered on the medium or midrange frequencies, such that the resolution of the sound generated is lower but on the other hand allows better intelligibility, in particular for people suffering from hearing impairment.

[0096] It will be understood that it is possible to combine in the same enclosure 1 cores 7 passing through a soundboard 8 and cores 7 not passing through a soundboard 8, for example to play on the frequency range reproduced by the enclosure 1.

[0097] According to the first embodiment and as can be better seen in Figures 3, 5 and 6, the rear face 3 comprises a through opening 32 configured to receive a loudspeaker 9, controlled by the control electronics. The loudspeaker 9 is preferably an extreme bass loudspeaker, or subwoofer, making it possible to obtain extreme bass frequencies, which are difficult to obtain solely by vibration of the enclosure 1 induced by the electromagnetic actuators 6.

[0098] It can be specified here in particular that the wavelengths which can be obtained by the enclosure 1 using the electromagnetic actuators 6 depend directly on the dimensions of the front face 2. The use of a loudspeaker 9 therefore makes it possible to obtain low frequencies, without requiring the use of a large front face 2, which therefore makes it possible to obtain a more compact enclosure 1 for the same range of restored wavelengths.

[0099] According to variants of the invention, the front face 2 and the casing 4 could also comprise through openings configured to receive loudspeakers, in addition to or replacing the loudspeaker 9 received in the rear face 3.

[0100] It is known that the efficiency of loudspeakers is low, in particular for subwoofer loudspeakers, and that the majority of the electrical energy consumed is transformed into heat. The applicant has discovered that the use of cores 7 according to the invention makes it possible to reduce dissipation and improve the efficiency of the loudspeaker 9 received in the rear face 3, which makes it possible to reduce the environmental footprint linked to the use of a speaker 1 according to the invention, and to extend the autonomy of the speaker 1 in the case of a portable speaker 1.

[0101] Furthermore, as shown in [Fig.6], preferably, the rear face 3 also receives a vent 10, for example in the form of a cardboard or PVC tube, of the bass-reflex speaker type.

[0102] According to a non-preferred variant, the electromagnetic actuators 6 can be directly fixed to the front face 2, preferably by screwing. It will then be understood that, in this case, the cores 7 do not pass through a soundboard 8.

[0103] When the electromagnetic actuators 6 are directly fixed to the front face 2, the enclosure 1 preferably comprises a reinforcing member 12 arranged on the surface 21 of the front face 2 facing the rear face 3, at angles between the front face 2 and the casing 4. Such a reinforcing member 12 is for example shown in dotted lines in Figures 2 to 4. The reinforcing member 12 is fixed both to the front face 2 and to the casing 4, preferably by screwing, so as to reinforce the connection between the front face 2 and the casing 4. The reinforcing member has in particular the effect of promoting a transfer of vibrations between the front face 2 and the casing 4. The reinforcing member 12 can for example be formed by cleats screwed to the front face 2 and to the casing 4.

[0104] According to a second embodiment of the invention (not shown), the enclosure 1 further comprises secondary cores.

[0105] Each secondary core is a solid element, preferably a cylinder or a bar, which extends longitudinally between a part of the envelope 4 and another part of the envelope 4 located opposite, for example between a left lateral face of the envelope 4 and a right lateral face of the envelope 4, or between an upper face of the envelope 4 and a lower face of the envelope 4.

[0106] Each secondary core has a first end force-fitted into a recess formed in the casing 4 and a second end, opposite the first end, force-fitted into another recess formed in the casing 4, such that each secondary core transmits vibrations between two corresponding parts of the casing 4.

[0107] According to the second embodiment, the recesses are in the form of through openings, respectively passing right through the casing. Alternatively, the recesses could also be blind holes. According to another variant, the secondary cores could also be connected to the casing 4 by means of connecting elements in which the respective ends of the secondary cores are force-fitted, said connecting elements being mechanically connected to the casing 4, for example by screwing, nailing or gluing.

[0108] The applicant has discovered that the use of secondary cores makes it possible to accentuate the medium frequencies and to improve the intelligibility of the sound generated by the speaker 1, in particular for people suffering from hearing impairment. This configuration is particularly advantageous in a combination of cores 7 connecting the front face 2 to the rear face 3 without passing through a soundboard 8, soundboards 8 being used or not and cores 7 passing through a soundboard 8 being used or not.

[0109] It can be specified that, to guarantee the proper functioning of the enclosure 1 according to the invention: - the envelope 4 is made of a material having an average density greater than or equal to an average density of a material in which the front face 2 is made and to an average density of a material in which the rear face 3 is made, - where appropriate, the or each soundboard 8 is made of a material having an average density less than or equal to the average density of the material of the front face 2, - the or each core 7 is made of a material having an average density less than or equal to the average density of the material of the front face 2 and to the average density of the material of the rear face 3, - where appropriate, the or each core 7 passing through a soundboard 8 is made of a material having an average density less than or equal to the average density of the material of the respective soundboard 8 that it passes through, - where applicable, the or each secondary core is made of a material having an average density less than or equal to the density average of the envelope material 4, and - where appropriate, the reinforcing member 12 is made of a material having an average density greater than or equal to the average density of the material of the envelope 4.

[0110] It can also be specified that the use of soundboards 8 having an average density less than or equal to the average density of the front face 2 makes it possible to guarantee good transfer of vibrations between the electromagnetic actuators 6 and the front face 2.

[0111] It can also be specified that the use of cores 7 having an average density less than or equal to the average density of the front face 2, to the average density of the rear face 3 and to the average density of the envelope 4 makes it possible to obtain a “mass-spring” effect and to guarantee a good transfer of vibrations between the front face 2 and the rear face 3 via the cores 7. The use of cores 7 having an excessively high average density would produce a muted effect and could cause the enclosure 1 to resonate, which could even lead to a displacement of the enclosure 1 caused by excessive vibrations thereof.

[0112] Preferably, the front face 2, the rear face 3 and the envelope 4 are made of the same material.

[0113] According to the invention, the front face 2, the rear face 3 and the envelope 4 are preferably made of medium density fibreboard, or MDF, having an average density of 650 kg / m3, but could also be made of another material having, preferably, an average density of between 500 and 750 kg / m3, for example expanded polyvinyl chloride, or expanded PVC, for example of the Forex® type having an average density of 500 kg / m3.

[0114] Where appropriate, the reinforcing member 12 is preferably made of the same material as the casing 4.

[0115] The soundboards 8 are preferably made of Okoume, for example an Okoume laminate, for example of the Teboply type, having an average density of 500 kg / m3 but could also be made of another material having, preferably, an average density of between 400 and 600 kg / m3, for example another type of wood. It will be understood that the enclosure 1 may, as a variant, comprise soundboards 8 made of different materials, for example to tune the enclosure 1 or to play on the range of wavelengths restored.

[0116] The cores 7, and where appropriate the secondary cores, are preferably made of solid wood, for example beech, having an average density of between 350 and 400 kg / m3 but could also be made of another material. preferably having an average density of between 275 and 475 kg / m3, for example another type of wood. It will be understood that the enclosure 1 may, as a variant, comprise cores 7, where appropriate secondary cores, made from different materials, for example to tune the enclosure 1 or to play on the range of wavelengths restored.

[0117] It will also be understood that an enclosure 1 according to the invention could also be composed of a composite material, for example a polymer reinforced with fibers, for example natural fibers.

[0118] The applicant has discovered that for an enclosure 1 according to the embodiment shown in [Fig.l] for which the front face 2, the rear face 3 and the casing are made of the same material, it is advantageous for the front face 2 to be less thick than the rear face 3 and the casing 4, which in particular facilitates vibration of the front face 2 using the electromagnetic actuators 6 and reduces the associated energy dispersion.

[0119] Preferably, the envelope 4 and the rear face 3 have the same thickness.

[0120] For example, for an enclosure such as shown in [Fig.l] having dimensions of 33 x 23 x 18 cm and a front face 2, a rear face 3 and an envelope 4 made of MDF, for example of the Fibromax Pro type, the front face 2 may have a thickness of 10 mm, and the rear face 3 and the envelope 4 a thickness of 19 mm.

[0121] According to another example, for a front face 2, a rear face 3 and an envelope 4 made of expanded PVC, for example of the Forex® type, the front face 2 may have a thickness of 12 mm, and the rear face 3 and the envelope 4 a thickness of 22 mm.

[0122] In the two examples above, the soundboards 8 are preferably made of Okoume and have a thickness of 5 mm, and the cores 7 are preferably made of Beech and have a diameter of 14 mm.

[0123] As mentioned above, the soundboards 8 can be replaced by a reinforcing member 12, for example composed of square section cleats, for example 10 or 15 mm.

[0124] Preferably, the enclosure is fully assembled by screwing and force fitting, without glue.

[0125] Table 1 below presents spatial decay measurements for a speaker 1 according to the first embodiment of the invention and for a “classic” speaker with Yamaha brand loudspeakers, in a room with an ambient noise of 33 dB.

[0126] [Tables 1] Location Frequency (Hz) Distance (m) Yamaha - dB Level Invention - dB Level A 500 0.8 62 62 B 500 3.6 54 57 C 500 3.8 50 57 D 500 6.3 40 47 E 500 6.3 34 44 F 500 7.1 41 46 G 500 6.1 46 54 H 500 5.6 33 44 I 500 5 33 50 J 500 2.7 37 49

[0127] It can be seen that the spatial decrease is much lower for enclosure 1 according to the first embodiment of the invention.

[0128] [Fig.7] schematically shows the measurement locations and the environment of the room in which the measurements were carried out.

[0129] In position E, a sound mask is arranged between the measuring device and the measured enclosure. In position F, a sound mask and an absorbent object are arranged between the measuring device and the measured enclosure. In position H, an acoustic partition is arranged on the left of the measuring device. In position I, an acoustic partition is arranged on the right of the measuring device. A sound mask corresponds to an object interposed between the measured enclosure and the measuring device, an absorbent object is an object with a sound absorption function and an acoustic partition is a partition with a sound absorption function.

[0130] Furthermore, in order to improve the aesthetics of the enclosure 1, the latter may comprise a covering 11, for example a fabric or a canvas, as shown in [Fig.6], or even a print applied to the front face 2, the rear face 3 and the casing 4.

[0131] It is understood that the particular embodiments which have just been described have been given for informational purposes and are not limiting, and that modifications may be made without departing from the scope of the present invention.

Claims

Claims

1. - Enclosure (1) configured to generate low decay sound spatial and without resonance effect in a reverberant medium, characterized by the fact that the enclosure (1) comprises: - a front face (2); - a rear face (3), arranged opposite the front face; - an envelope (4), having an average density greater than or equal to an average density of the front face (2) and an average density of the rear face (3), connecting the front face (2) to the rear face (3) and enclosing an interior space (5) defined between the front face (2) and the rear face (3); - at least one electromagnetic actuator (6), the or each electromagnetic actuator (6) being arranged in the interior space (5) and mechanically connected to a surface (21) of the front face (2) facing the rear face (3) and being configured to generate vibrations in the front face (2) from a control signal; - at least one solid core (7), the or each core (7) having an average density less than or equal to the average density of the front face (2) and the average density of the rear face (3), the or each core (7) extending between the front face (2) and the rear face (3) and having a first end force-fitted in a recess (22) formed in the front face (2) and a second end, opposite the first end, force-fitted in a recess (31) formed in the rear face (3), such that the or each core (7) transmits vibrations between the front face (2) and the rear face (3); and - control electronics configured to deliver control signals to the electromagnetic actuator (6) or to each electromagnetic actuator (6) so as to generate a sound by vibrating the front face (2), the at least one core (7), the casing (4) and the rear face (3).

2. - Enclosure (1) according to claim 1, characterized in that the enclosure further comprises at least one solid secondary core, the or each secondary core having an average density less than or equal to the average density of the envelope, the or each secondary core extending between a part of the envelope (4) and another part of the envelope (4) located opposite, and the or each secondary core having a first end force-fitted in a recess formed in the casing and a second end, opposite the first end, force-fitted into another recess formed in the casing, such that the or each secondary core transmits vibrations between two corresponding parts of the casing (4).

3. - Enclosure (1) according to claim 1 or claim 2, characterized in that the enclosure (1) further comprises a reinforcing member (12) arranged on the surface (21) of the front face (2) facing the rear face (3), at angles between the front face (2) and the casing (4), said reinforcing member (12) being connected to both the front face (2) and the casing (4), and said reinforcing member (12) having an average density greater than or equal to the average density of the casing (4).

4. - Enclosure (1) according to claim 1 or claim 2, characterized in that the enclosure (1) further comprises at least one soundboard (8) fixed to the front face (2) in the interior space (5), the or each soundboard (8) having an average density less than or equal to the average density of the front face, the or each soundboard (8) comprising a first contact surface (81) configured to be brought into contact with the surface (21) of the front face (2) facing the rear face (3), and a second contact surface (82), opposite the first contact surface (81) of said soundboard (8), configured to receive at least one electromagnetic actuator (6), such that the or each soundboard (8) forms an interface between the front face (2) and the at least one electromagnetic actuator (6),such that vibrations are generated in the soundboard (8) by the at least one electromagnetic actuator (6) and then generated in the front face (2).,

5. - Enclosure (1) according to claim 4, characterized in that at least one core (7) has its first end force-fitted both in the respective recess (22) formed in the front face (2) and in a through opening (83) formed in a soundboard (8), so as to pass through said soundboard (8), the enclosure (1) being configured such that the or each core (7) passing through a soundboard (8) has an average density less than or equal to the average density of the respective soundboard (8) through which it passes.

6. - Enclosure (1) according to claim 4 or claim 5, ca-

7.

8.

9.

10.

11.

12.

13.

14. characterized by the fact that at least one soundboard (8) has a first contact surface (81) in the shape of an “egg” having three marked roundings. - Enclosure (1) according to claim 6 taken as a dependency of claim 5, characterized in that, for said at least one soundboard (8) having a first contact surface in the shape of an "egg", a core (7) is mounted on one side of the tip of the egg and an electromagnetic actuator (6) is fixed on a side opposite the tip of the egg. - Enclosure according to any one of claims 4 to 7, characterized in that at least one soundboard (8) has a first contact surface (81) in the shape of an “L”. - Enclosure (1) according to claim 8 taken as a dependency of claim 5, characterized in that, for said at least one soundboard (8) having a first contact surface (81) in the shape of an “L”, one of the following configurations is respected: - a core (7) is mounted at the distal end of one of the cross member and the shaft of the "L", and an electromagnetic actuator (6) is attached to the distal end of the other of the cross member and the shaft of the "L"; and - a core (7) is mounted at the intersection of the cross member and the shaft of the "L", a first electromagnetic actuator (6) is attached to the distal end of the cross member of the "L", and a second electromagnetic actuator (6) is attached to the distal end of the shaft of the "L". - Enclosure (1) according to any one of claims 1 to 9, characterized in that at least one core (7) is cylindrical in shape. - Enclosure (1) according to any one of claims 1 to 10, characterized in that the front face (2) and the rear face (3) are flat. - Enclosure (1) according to claim 11, characterized in that the front face (2) and the rear face (3) are parallel. - Enclosure according to claim 12, characterized in that the envelope (4) comprises two lateral faces, an upper face and a lower face, such that the front face (2), the envelope (4) and the rear face (3) define a straight block. - Enclosure according to any one of claims 1 to 13, characterized in that the front face (2), where appropriate the reinforcing member (12), the casing (4) and the rear face (3) are assembled by screwing.

15. - Enclosure (1) according to claim 4 or according to any one of claims 5 to 14 taken as a dependency of claim 4, characterized in that at least one soundboard (8) is fixed to the front face (2) by a plurality of screws and that at least one electromagnetic actuator (6) is fixed to said at least one soundboard (8) by screwing.

16. - Enclosure (1) according to claim 15, characterized in that screws of the plurality of screws have at least two different lengths.

17. - Enclosure (1) according to claim 15 or claim 16, characterized in that said at least one soundboard (8) fixed to the front face (2) by a plurality of screws comprises a plurality of pre-drilled holes configured to receive screws according to different configurations for fixing to the front face (2), in order to allow tuning of the enclosure (1) according to thicknesses and materials of the at least one soundboard (8), the front face (2), the at least one core (7), the casing (4) and the rear face (3).

18. - Enclosure (1) according to any one of claims 1 to 17, characterized in that a thickness of the rear face (3) is greater than or equal to a thickness of the front face (2).

19. - Enclosure according to any one of claims 1 to 18, characterized in that at least one of the front face (2), of the at least one core (7), of the casing (4), of the rear face (3), where appropriate of the at least one soundboard (8), where appropriate of the reinforcing member (12), and where appropriate of the at least one secondary core is composed of a material chosen from: solid wood, a medium density fiberboard, or MDF, and expanded polyvinyl chloride, or expanded PVC.

20. - Enclosure (1) according to any one of claims 1 to 19, characterized in that the front face (2), the rear face (3), the casing (4) and, where appropriate, the reinforcing member (12) have an average density of between 500 and 750 kg / m3, preferably 650 kg / m3, that, where appropriate, the or each soundboard (8) has an average density of between 400 and 600 kg / m3, preferably 500 kg / m3, and that the or each core (7), and where appropriate the or each secondary core, has an average density of between 275 and 475 kg / m3, preferably between 350 and 400 kg / m3.

21. - Enclosure (1) according to any one of claims 1 to 20, characterized in that the rear face (3) further comprises a

22.

23. through opening (32) configured to receive a loudspeaker (9), preferably a subwoofer, or subwoofer, controlled by the control electronics. - Enclosure (1) according to any one of claims 1 to 21, characterized in that the rear face (3) comprises a vent (10). - Enclosure (1) according to any one of claims 1 to 22, characterized in that the enclosure (1) is of the portable type and comprises a battery configured to power the enclosure (1).

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