FR3050600A1 - DEVICE FOR DIFFUSION OF SOUNDS WITH PASSIVE RADIATORS AND EVENT BASS-REFLEX. - Google Patents

Abstract

A sound diffusion device (1) comprises: - a main body (2) having two first housings (41) housing loudspeakers, and a first central part (5) having a first face (9) provided with a opening (10) communicating with a second housing (8), and two ducts (61) connecting the first housing (41) to the second housing (8), and - an auxiliary body (3) having a second central portion (10) accommodated in the second housing (8) and comprising two opposite faces (131-132) open and on which are secured two passive radiators (151-152) separated by a vacuum zone (16) and synchronously biased in opposition, and a conduit exhaust system (12) passing through the opening (10) and communicating with the void area (16) and the outside defining a "bass-reflex" vent generating low frequency sounds when the passive radiators (151-152) are solicited by the speakers.

Description

SOUND DELIVERY DEVICE WITH PASSIVE RADIATORS AND BASS-REFLEX VENT. The invention relates to sound diffusion devices that can be part of an equipment.

In some areas, such as seats (possibly vehicle), sound diffusion devices comprising a body having two first housing communicating with the outside and each housing a speaker, a central portion having a second housing communicating with the outside through an opening in which is housed a passive radiator, and two ducts each communicating with one of the first housing and the second housing.

The term "passive radiator" here means a set of elements comprising a frame, possibly circular, a membrane securely fixed to the frame and secured to the membrane.

When the speakers are electrically excited to broadcast sounds, they induce in both ducts air pressure variations that will solicit the passive radiator. This solicitation causes the generation of low frequency sounds that complement the midrange and high frequency sounds generated by the speakers. Alas, the aforesaid solicitation induces vibrations of the frame that propagate at least to the body of the sound diffusion device, as well as possibly to a part of an equipment of which the latter is part (such as a seat), which can be a nuisance for the person who uses it. The invention is therefore particularly intended to improve the situation.

It proposes for this purpose a sound diffusion device comprising a main body having two first housing communicating with the outside and each housing a loudspeaker, a first central portion having a second housing, and two conduits each communicating with the one of the first housing and the second housing.

This sound diffusion device is characterized by the fact that: the first central part of its main body comprises a first face provided with an opening communicating with the second housing, and that it also comprises an auxiliary body comprising: on the one hand, a second central portion housed in the second housing and comprising two opposite faces between which is defined a third housing and on which are secured respectively two passive radiators separated by a vacuum zone and adapted to be synchronously biased in opposition and, on the other hand, an exhaust duct passing through this opening and communicating with the empty zone and the outside by defining a so-called "bass-reflex" type vent capable of generating low frequency sounds when the radiators Passives are solicited by air pressure variations induced by the loudspeakers.

The passive radiators being synchronously biased in opposition, the opposing vibrations of their membranes are not transmitted to their frames. In addition, the cooperation of passive radiators with the bass-reflex vent makes it possible to generate low frequencies with a resonance effect.

The sound diffusion device according to the invention may comprise other characteristics that can be taken separately or in combination, and in particular: the evacuation duct may comprise a first end edge communicating with the outside and comprising a an inner edge inclined with respect to an average direction of air expulsion from the empty area, and a second end edge communicating with the void area and including an inner edge inclined with respect to the average direction; the inner edges of the first and second end edges may be rounded. Alternatively, the inner edges of the first and second edges may be inclined relative to the average direction at an angle of between 40 ° and 60 °; the passive radiators may be spaced from each other by a distance of between 8 mm and 20 mm; the opposite faces of the second central portion may be perpendicular to the first face; - The first housing may have open faces communicating with the outside and respectively contained in planes which intersect at an angle between 75 ° and 179 °. The invention also proposes a seat comprising at least one backrest, a seat, and at least one sound diffusion device of the type of that presented above.

For example, the sound diffusion device may be part of a seat element which is selected from its backrest and a headrest that equips its file. The invention also proposes a vehicle, possibly of automobile type, and comprising at least one seat of the type of that presented above. Other characteristics and advantages of the invention will appear on examining the detailed description below, and the accompanying drawings (obtained in CAD / CAD ("Computer Aided Design / Computer Aided Drawing"), of where the apparently discontinuous character of certain lines), in which: FIG. 1 schematically illustrates, in a perspective view, an exemplary embodiment of a sound diffusion device according to the invention before it becomes part of FIG. 2 schematically illustrates, in a perspective view, an exemplary embodiment of an auxiliary body of the sound diffusion device of FIG. 1, without its passive radiators, and FIG. 3 schematically illustrates the sound diffusion device of Figure 1 in a sectional view along the axis III-III. The purpose of the invention is notably to propose a sound diffusion device 1 that can be part of a reception equipment.

In what follows, it is considered, by way of non-limiting example, that the sound diffusion device 1 is intended to equip a seat. For example, this sound diffusion device 1 can equip the upper part of a seat back, or a headrest of a seat back. But a sound diffusion device 1 according to the invention may be part of other home equipment, such as a headboard or a partition of building or armchairs or sofas.

Furthermore, it is considered in the following, by way of non-limiting example, that the seat is intended to equip a vehicle, possibly of automotive type (such as a car). But the invention is not limited to this application. It concerns any type of vehicle (land, sea (or fluvial), or air), and any building.

FIG. 1 schematically shows a non-limiting exemplary embodiment of a sound diffusion device 1 according to the invention, before it forms part of an equipment item (here a vehicle seat).

As illustrated, a device (sound diffusion) 1 according to the invention comprises at least one main body 2 and an auxiliary body 3, coupled to each other.

The main body CP comprises two first housings 4j (j = 1 or 2), a first central portion 5, and two ducts 6j.

The first two housings 4j are defined in two lateral parts 1 1 of the main body CP, communicate with the outside and each house a loudspeaker (not shown).

Preferably, and as illustrated in non-limiting manner in FIGS. 1 and 3, the first housings 4j have open faces which communicate with the outside and which are respectively contained in planes which intersect at an angle of between 75 ° and 179 °. °. This option is intended to direct the sounds generated by the speakers to the ears of the passenger who is here sitting on the seat equipped with the device 1, to optimize listening. More preferably, these two planes intersect at an angle of between 120 ° and 155 °.

The first central portion 5 (of the main body 2) comprises a second housing 8 and a first face 9 which is provided with an opening 10 communicating with the second housing 8 (see Figure 3). Here, the first face 9 is an upper face, but it could be a lower or lateral face, depending on the needs and / or according to the configuration of the equipment of reception of the device 1.

The two ducts 6j (of the main body 2) each communicate with one of the first housing 4j and the second housing 8. Thus, when the loudspeakers are electrically excited to broadcast sounds, they induce in the rear parts of their first housings 4j (opposed to outside) variations of air pressure which propagate in the two ducts 6j into the second housing 8.

The main body 2, which constitutes what the skilled person sometimes calls a "cabinet", is made of a very rigid material, so as not to be deformable in the presence of pressure variations. Thus, it can, for example, be made of a plastic material, in order to be easily molded.

As best shown in FIGS. 2 and 3, the auxiliary body 3 comprises a second central portion 11 and an evacuation duct 12.

The second central portion 11 (of the auxiliary body 3) is housed, preferably removably, in the second housing 8. It comprises two opposite faces 13k (k = 1 or 2) between which is defined a third housing 14 and on which are secured respectively respectively two passive radiators 15k (see Figure 3).

In the example illustrated nonlimitingly in FIGS. 1 to 3, the opposite faces 13k are perpendicular to the first face 9.

The passive radiators 15k are separated from each other by a void area 16 and are adapted to be synchronously biased in opposition. For this purpose, the two passive radiators 15k are identical and mounted in opposite ways, so that a solicitation of one (15k) of them by air pressure variations, induced by the loudspeakers and reached in the second housing 8, induces the same variation of air pressure in the empty zone 16 as that induced by the other passive radiator 15k.

For example, and as illustrated nonlimitingly in FIG. 3, each passive radiator 15k comprises a frame 17, a membrane 18 secured to the frame 17, and a mass 19 secured to the membrane 18.

The frame 17 can take various forms. Thus, in the example shown non-limitatively in Figures 1 to 3, the frame 17 is substantially rectangular. But in alternative embodiments it could be square or round.

It is important to note that each membrane 18 must be securely attached to the corresponding frame 17 in a very hermetic manner, so as not to let air. Similarly, each frame 17 must be securely fixedly secured to the corresponding face 13k of the second central portion 11, so as not to let air. Thus, only the vibrations induced by the membranes 18 cause variations in air pressure in the empty zone 16.

The exhaust duct 12 (of the auxiliary body 3) passes through the opening 9 defined in the first (upper) face 9 of the first central portion 5 of the main body 2. This exhaust duct 12 communicates with the empty zone 16 and the outside (via an opening 20) by defining a so-called "bass-reflex" type vent capable of generating low frequency sounds when the passive radiators 15k are subjected to high pressure induced air pressure variations. Speakers.

It will be understood that the vibrations generated by the passive radiators 15k in the empty zone 16 push the air present in the latter (16) into the discharge duct 12 along the arrow F of FIG. 3, since the hermeticity of the the empty zone 16 on the side of the third housing 14 forces this air to reach the outside through the opening (here upper) 20 of the exhaust duct 12. The bass-reflex vent can thus generate sounds whose frequencies can be significantly less than 100 Hz, and a resonance effect is obtained due to the opposite actions of the passive radiators 15k.

The passive radiators 15k being synchronously biased in opposition, the opposing vibrations of their membranes 18 are not transmitted to their respective frames 17. This results from the fact that at the moment when a membrane 18 advances, the pressure of the air increases in front of, but decreases behind, and inversely when it recedes, and therefore the operations in opposition make it possible to suppress the effects of their vibrations on their Frames 17. The space between the passive radiators 15k may be a function of the desired frequency. For example, the passive radiators 15k may be spaced from each other by a distance of between 8 mm and 20 mm. It is therefore possible to generate low frequencies with resonance effect in a restricted volume, particularly well suited to implantation in a constrained environment (such as for example in an upper part of a seat backrest or in a headrest of a backrest seat). Thus, the implantation of the device 1 is easier and can in particular be in the axis of a folder or a headrest file.

It will be noted, as illustrated without limitation in FIG. 3, that in order to optimize the generation of the low frequencies, it is preferable for the evacuation duct 12 to comprise first 21 and second 22 opposite end edges, one to the other and whose internal parts do not form a right angle (90 °). More specifically, it is preferable that the first end edge 21 (which defines the upper opening 10 and therefore communicates with the outside) comprises an inner edge inclined relative to an average direction of expulsion of air which is from the empty zone 16, and the second end edge 22 (which communicates with the empty zone 16) comprises an inner edge inclined relative to this mean direction.

For example, and as illustrated not limitationatively in Figure 3, the inner portions of the first 21 and second 22 end edges may be rounded. Alternatively, the inner portions of the first 21 and second 22 end edges may be inclined relative to the average direction at an angle which is between 40 ° and 60 °. For example, this angle may be equal to 45 °.

Note also that the opening 20 of the exhaust duct 12 may take various forms, and in particular a substantially rectangular or square (possibly with rounded "angles") or elliptical, for example.

It will be noted that the external face of the evacuation duct 12 (of the auxiliary body 3) can be extended, substantially perpendicularly, in an intermediate portion, by a wall 23 intended to rest on the first (upper) face 9 of the first central portion. 5 of the main body 2. This wall 23 comprises a curved end edge (here downwards) so as to be substantially pressed against the faces of this first central portion 5, opposite to each other and substantially perpendicular to the first face (upper). 9. This advantageously makes it possible to position the second central portion 11 relatively to the first central portion 5, and in particular the passive radiators 15k in the second housing 8, but also to seal the latter (8). .

It will also be noted that the wall 23 may optionally be fixedly affixed to the first (upper) face 9, for example by screwing, sealing or bonding, in order to prevent the auxiliary body 3 from moving relative to the main body 2 .

It will also be noted that the auxiliary body 3, which defines a kind of cassette, is made of a very rigid material so as not to be deformable in the presence of pressure variations. Thus, it can, for example, be made of a plastic material, in order to be easily molded.

It will also be noted, as illustrated without limitation in FIGS. 1 and 3, that the auxiliary body 3 may comprise one or more fastening tabs 24, 25 intended to allow it to be secured to its reception equipment and / or the fastening of the unless another element is part of its equipment of reception.

Claims (10)

A sound diffusion device (1) comprising a main body (2) comprising i) two first housings (4j) communicating with the outside and each housing a loudspeaker, ii) a first central portion (5) comprising a second housing (8), and iii) two ducts (6j) each communicating with one of said first housings (4j) and said second housing (8), characterized in that said first central portion (5) comprises a first face ( 9) provided with an opening (10) communicating with said second housing (8), and in that it further comprises an auxiliary body (3) comprising a) a second central portion (11) housed in said second housing ( 7) and comprising two opposite faces (13k) between which is defined a third housing (14) and on which are secured respectively two passive radiators (15k) separated by a void area (16) and adapted to be synchronously biased in opposition, and b) a exhaust duct (12) passing through said opening (10) and communicating with said empty zone (16) and the outside by defining a so-called "bass-reflex" type vent adapted to generate low frequency sounds when said passive radiators (15k) are solicited by variations in air pressure induced by said speakers. 2. Device according to claim 1, characterized in that said discharge duct (12) comprises a first end edge (21) communicating with the outside and comprising an inner edge inclined relative to an average direction of expulsion air from said empty zone (16), and a second end edge (22) communicating with said empty zone (16) and including an inner edge inclined with respect to said mean direction. 3. Device according to claim 2, characterized in that said inner edges of the first (BE1) and second (BE2) end edges are rounded. 4. Device according to claim 2, characterized in that said inner edges of the first (21) and second (22) end edges are inclined relative to said mean direction at an angle between 40 ° and 60 °. 5. Device according to one of claims 1 to 4, characterized in that said passive radiators (15k) are spaced from each other by a distance of between 8 mm and 20 mm. 6. Device according to one of claims 1 to 5, characterized in that said opposite faces (13k) are perpendicular to said first face (9). 7. Device according to one of claims 1 to 6, characterized in that said first housing (4j) have open faces communicating with the outside and respectively contained in planes which intersect at an angle between 75 ° and 179 °. 8. Seat comprising at least one backrest and a seat, characterized in that it further comprises at least one sound diffusion device (1) according to one of the preceding claims. 9. Seat according to claim 8, characterized in that said sound diffusion device (1) is part of an element selected from a group comprising said folder and a headrest equipping said folder. 10. Vehicle, characterized in that it comprises at least one seat according to one of claims 8 and 9.