Bass reflex type loudspeaker enclosure

Abstract

Bass reflex type loudspeaker enclosure comprising a cabinet (6), a loudspeaker (7) and a first vent (10). The acoustic loudspeaker enclosure further comprises a second vent (11) and an internal heat sink (12) which is located inside the cabinet and intended to be thermally coupled to an electrical component (4) in order to dissipate, inside the cabinet, heat produced by the electrical component, the first vent, the second vent and the internal heat sink being positioned so that an air flow (F) which flows through the first vent, the second vent and into the cabinet moves the heat produced by the electrical component out of the cabinet.

Description

[0001] The invention relates to the field of bass-reflex type acoustic speakers. BACKGROUND OF THE INVENTION

[0002] Many modern electrical devices incorporate a speaker designed to reproduce an audio signal. These devices include residential gateways, set-top boxes, televisions, voice assistants, etc.

[0003] A speaker enclosure used in this type of electrical equipment typically consists of a cabinet and a loudspeaker attached to the cabinet. The loudspeaker reproduces the audio signal by generating sound waves outside the cabinet. These sound waves are produced by the loudspeaker from an electrical current supplied to a voice coil by an audio amplifier.

[0004] The low-frequency performance of a loudspeaker can be improved by adding a port to the cabinet. This is known as a "bass-reflex" speaker. The air flowing through the port between the cabinet's interior (behind the speaker) and the exterior (in front of the speaker) creates a mechanical system that resonates at a specific frequency.

[0005] We are obviously looking to reduce the cost and size of this electrical equipment.

[0006] Document EP 1 581 025 A2 describes an electronic device incorporating a loudspeaker. SUBJECT OF THE INVENTION

[0007] The invention aims to reduce the cost and size of electrical equipment such as that just described. SUMMARY OF THE INVENTION

[0008] To achieve this goal, a bass-reflex type acoustic enclosure is proposed according to claim 1a.

[0009] The internal heat sink is positioned inside the enclosure. This minimizes the overall space required for both cooling the electrical component and reproducing the sound. Consequently, the overall size of the electrical equipment incorporating the acoustic enclosure according to the invention is reduced.

[0010] Because airflow naturally circulates within the enclosure through the first and second vents, a fan is not required for improved cooling. This reduces the cost of electrical equipment incorporating the acoustic enclosure according to the invention.

[0011] We also propose an acoustic device comprising an acoustic enclosure such as the one just described, and an electrical board on which the electrical component is mounted.

[0012] In addition, electrical equipment is proposed that includes an acoustic device such as the one just described.

[0013] Other features and advantages of the invention will become apparent from the following description of particular, non-limiting embodiments of the invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Reference will be made to the attached drawings, among which: there figure 1 represents a sound enclosure; the figure 2 represents a sound enclosure; the figure 3 represents an acoustic enclosure figure 4 represents a sound enclosure; the figure 5 represents a sound enclosure; the figure 6 represents a sound enclosure; the figure 7 represents an acoustic enclosure according to an embodiment of the invention; the figure 8 represents an internal heat sink for the acoustic enclosure according to this embodiment of the invention; the figure 9 represents a sound enclosure DETAILED DESCRIPTION OF THE INVENTION

[0015] With reference to the figure 1 A residential gateway 1 includes an electrical board 2 comprising a plurality of electrical components 3 belonging to an audio amplifier (i.e., the electrical components 3 contribute to implementing an audio amplifier function). The audio amplifier produces an electrical current used to reproduce an audio signal.

[0016] Electrical component 4 is, among electrical components 3, the electrical component that generates the most heat.

[0017] The residential gateway 1 also includes an acoustic enclosure according to a first embodiment of the invention 5.

[0018] The acoustic enclosure 5 comprises a box 6 defining an internal cavity of defined volume, and a loudspeaker 7. The loudspeaker 7 is located on a first face 8 of the box 6, which here is a front face of the box 6.

[0019] Speaker 7 contains a voice coil. The electrical current produced by the audio amplifier flows through the voice coil of speaker 7 so that speaker 7 generates sound waves and thus reproduces the audio signal.

[0020] The acoustic enclosure 5 also includes a first vent 10 and a second vent 11.

[0021] The first vent 10 is located near one end of the first face 8. The first end is an upper end. The second vent 11 is located near a second end of the first face 8. The second end is a lower end. By "near," we mean that the maximum distance between a vent and an end of the face is less than one-third of the total length of the face.

[0022] The first vent 10 extends horizontally from the first face 8 into the box 6. The second vent 11 extends horizontally from the first face 8 into the box 6.

[0023] Of course, the terms "upper", "lower", "horizontally" and "vertically" must be interpreted in a configuration where the acoustic enclosure 5 is positioned in a nominal operating position.

[0024] Speaker 7 is positioned here between the first vent 10 and the second vent 11.

[0025] The first vent 10 and the second vent 11 are positioned and sized to allow natural air circulation within the acoustic enclosure 5, so that an airflow F naturally flows through the second vent 11, into the enclosure 6, and through the first vent 10. The direction of the airflow F may, of course, be different from that shown in the diagram. figure 1 .

[0026] The first vent 10 and the second vent 11 are also positioned and sized to optimize the acoustic performance of the acoustic enclosure 5, particularly in the low frequencies.

[0027] The sizing of the first vent 10 and the second vent 11, both of the "bass-reflex" type, is obtained by using, for each vent, the definition of a Helmholtz resonator.

[0028] Thus, for each event: λ / 2 2 = L + k . ϕ . V / S , where λ is the wavelength of the vent's resonant frequency, L is the vent's length, Ø is the vent's diameter, V is the defined volume of the internal cavity of the box 6, and S is the vent's cross-sectional area. The coefficient k represents the degree of discontinuity at the vent's ends. The coefficient k tends towards 0.5 if the vent's terminations are flared. The coefficient k tends towards 1 if the vent's terminations are flush.

[0029] We also have: λ=c / F, where F is the wavelength of the resonance frequency and c is the speed of sound.

[0030] For example, to have a "bass-reflex" resonator at 100 Hz in an acoustic enclosure 5 with a defined volume of 3 litres, we can size the first vent 10 and the second vent 11 so that they each have a diameter of 4 cm and a length of 13 cm.

[0031] The acoustic enclosure 5 further comprises an internal heat sink 12, in this case a finned heat sink. The internal heat sink 12 comprises a base 13 and a plurality of fins 14 extending from the base 13 perpendicularly to the base 13.

[0032] When the internal heat sink 12 is mounted in the box 6, the internal heat sink 12 extends close to a second face 15 of the box 6 located opposite the first face 8. The second face 15 is therefore here a rear face of the box 6.

[0033] The base 13 of the internal heat sink 12 extends parallel to and is fixed to an internal wall of the second face 15. Here, "wall" refers to one side of a face. The fins 14 of the internal heat sink 12 then extend towards the interior of the housing 6.

[0034] The electrical board 2 of the residential gateway 1 is located outside the enclosure 6 of the acoustic enclosure 5. The electrical board 2 is positioned parallel to an external wall of the second face 15 of the enclosure 6 of the acoustic enclosure 5.

[0035] The base 13 of the internal heat sink 12 is thermally coupled to the electrical component 4 of the electrical board 2.

[0036] To achieve thermal coupling, the internal heat sink 12 includes a metal pin 17 which extends from the base 13 of the internal heat sink 12 on the side opposite the fins 14. When the internal heat sink 12 is mounted in the housing 6, the metal pin 17 extends through the second face 15 of the housing 6. When the acoustic enclosure 5 and the electrical board 2 are integrated into the residential gateway 1, the electrical component 4 is in contact with the metal pin 17. The thermal coupling is therefore a direct contact.

[0037] Thus, the heat produced by the electrical component 4 is dissipated by the internal heat sink 12 inside the casing 6. The airflow F, which also circulates along the internal heat sink 12 and over the fins 14 of the internal heat sink 12, carries away the heat produced by the electrical component 4 to the outside of the casing 6.

[0038] With reference to the figure 2 An acoustic enclosure 105 includes a fan 120. The fan 120 is positioned outside the acoustic enclosure 105, at the level of an inlet of the second vent 111. The fan 120 extends opposite the inlet of the second vent 111. By "inlet", we mean here the opening of a vent which opens outside the enclosure 106, and by "outlet", we mean here the opening of a vent which opens inside the enclosure 106.

[0039] Fan 120 is an axial propeller fan. The static pressure of fan 120 is relatively low, for example, less than 20 Pa or 30 Pa. The fan can therefore be mounted directly at the inlet of the second vent 111, and could also be mounted at an outlet of the second vent 111, or even inside the second vent 111.

[0040] It is possible to choose another type of fan, in particular a turbine fan with a higher static pressure, for example on the order of 100Pa or 150Pa. In this case, the fan 120 must be a few millimeters away from the second vent 111, for example 5 to 10mm, so as not to disrupt the performance of the second vent 111 while ensuring its air circulation function.

[0041] The choice of the 120 fan is based on acoustic criteria. The 120 fan is quiet and balanced. The 120 fan does not generate vibrations in the structure of the 105 speaker enclosure, and does not interfere with the primary function of the 105 speaker enclosure, which is to reproduce an audio signal.

[0042] The 120 fan is mounted using a damping device integrated into the 120 fan and located between the body of the 120 fan and the 106 housing. This flexible mounting helps to limit the transmission of residual vibrations produced by the 120 fan. The 120 fan could also be rigidly mounted by taking certain precautions to avoid the transmission of vibrations.

[0043] The dimensions of the second vent 111 must of course be compatible with the dimensions of the fan 120. The diameter of the fan 120 is here greater than that of the second vent 111.

[0044] The fan 120 improves the thermal performance of the acoustic enclosure 105. The fan 120 forces air circulation through the second vent 111, in the box 106 and through the first vent 110, as well as along the internal heat sink 112. The airflow F is therefore greater and the heat produced by the electrical component 104 is expelled to the outside of the box 106 of the acoustic enclosure 105 more efficiently.

[0045] It is noted that the small overpressure generated by this ventilation can be considered as a negligible continuous load for the loudspeaker 107 and for the first vent 110 and the second vent 111. The operation of the loudspeaker 107, the first vent 110 and the second vent 111 is not affected by this continuous load.

[0046] Note that the 120 fan could also be mounted at the inlet, outlet or inside the first 110 vent.

[0047] With reference to the figure 3 An acoustic enclosure 205 includes a fan 220. The fan 220 is positioned inside the acoustic enclosure 205, at the level of an outlet of the second vent 211. The diameter of the fan 220 is close to that of the second vent 211 (but it could be larger or smaller).

[0048] With reference to the figure 4 An acoustic enclosure 305 includes a first fan 320 and a second fan 321. The first fan 320 is positioned inside the acoustic enclosure 305, at the level of an outlet of the first vent 310. The second fan 321 is positioned inside the acoustic enclosure 305, at the level of an outlet of the second vent 311.

[0049] With reference to the figure 5 , it is noted that it is possible to position the electrical card 402 inside the box 406 of an acoustic enclosure according to a fifth embodiment of the invention 405.

[0050] The electrical board 402 extends parallel to and is fixed to the inner wall of the second face 415 (rear face). The base 413 of the internal heat sink 412 extends parallel to the inner wall of the second face 415. The electrical board 402 is positioned between the base 413 of the internal heat sink 412 and the inner wall of the second face 415. The metal pin 417 is in contact with the electrical component 404.

[0051] This configuration further improves the integration of the acoustic enclosure 405 including the internal heat sink 412 and the electrical board 402, and reduces the total volume required by the acoustic enclosure 405 including the internal heat sink 412 and by the electrical board 402.

[0052] Of course, it would be possible to add one or more fans to the 405 acoustic enclosure, positioned as described earlier.

[0053] With reference to the figure 6 , the internal heat sink 512 of a 505 acoustic enclosure is integrated into the structure of the 505 acoustic enclosure.

[0054] A flat surface of the internal heat sink 512 forms at least a portion of an external wall of one face of the enclosure 506. Here, in this case, this flat surface is a surface of the base 513 of the internal heat sink 512. The base 513 forms the entirety of the second face 515 (rear face) of the enclosure 506 of the acoustic enclosure 505.

[0055] The electrical board 502 then extends outside the enclosure 506 of the acoustic enclosure 505, parallel to the second face 515 of the enclosure 506. The metal pin 517 of the internal heat sink 512 is in contact with the electrical component 504.

[0056] The base 513 of the internal heat sink 512 and the rear face of the enclosure 506 are therefore combined. This reduces the mass and overall cost of the speaker 505, which performs both audio signal reproduction and heat dissipation, and consequently the mass and cost of the residential gateway in which the speaker 505 is integrated.

[0057] With reference to figures 7 et 8 , the internal heat sink 612 is again integrated into the structure of the acoustic enclosure according to an embodiment of the invention 605. The base 613 of the internal heat sink 612 again forms the entirety of the second face 615 (rear face) of the enclosure 606 of the acoustic enclosure 605.

[0058] The first vent 610 and the second vent 611 are integrated into the internal heat sink 612. The first vent 610 and the second vent 611 therefore extend inside the box 606 from the second face 615 of the box 606.

[0059] The first vent 610 and the second vent 611 are each formed by a cylinder that extends at least partially into the internal heat sink 612. The cylinder forming the first vent 610 extends between the two fins 614a, 614b. The cylinder forming the second vent 611 extends between the two fins 614c, 614d. One axis of each cylinder is perpendicular to the base 613 of the internal heat sink 612 and parallel to the planes in which the fins 614 extend. Note that the cylinders extend between two different pairs of fins, which is a possibility but not a requirement. For example, it would be conceivable for the axis of a vent to correspond to that of a fin.

[0060] The first vent 610, the second vent 611, and the internal heat sink 612 form a single unit. This single unit can, for example, be made entirely or partially of metal or thermal plastic, such as polyamide.

[0061] With reference to the figure 9 , a housing of a residential gateway 701 includes an acoustic enclosure 705. The acoustic enclosure 705 includes an internal heat sink 712. The residential gateway 701 also includes an external heat sink 722 positioned outside the acoustic enclosure 705.

[0062] The internal heat sink 712 and the external heat sink 722 are both finned heat sinks, similar to those already described.

[0063] The internal heat sink 712 is positioned inside the enclosure 706. The base 713 of the internal heat sink 712 is mounted against the inner wall of the second face 715 of the enclosure 706. The electrical board 702 extends parallel to the outer wall of the second face 715 (rear face) of the enclosure 706, outside the enclosure 706.

[0064] The external heat sink 722 is positioned outside the enclosure 706. A base 723 of the external heat sink 722 extends parallel to the outer wall of the second face 715 of the enclosure 706. The fins 724 of the external heat sink 722 extend from the base 723, perpendicular to the base 723, towards a face 725 of the housing of the residential gateway 701 located opposite the first face 708 (front face) of the acoustic enclosure 705 (and of the residential gateway 701).

[0065] The external heat sink 722 is also thermally coupled to the electrical component 704. The external heat sink 722 has a metal pin 727 for this purpose, which makes contact with the electrical component 704. The metal pin 717 of the internal heat sink 712, for its part, makes contact with a surface of the printed circuit board of the electrical board 702 extending under the electrical component 704.

[0066] We note that the first vent 710 is again located near the first end of the first face 708, and that the second vent 711 is again located near the second end of the first face 708.

[0067] This time, however, the first vent 710 extends vertically inside the box, from a third face 730. The third face is a top face of the box 706.

[0068] Similarly, the second vent 711 extends vertically inside the box, from a fourth face 731. The fourth face is a lower face of the box 706.

[0069] Of course, the invention is not limited to the embodiments described, but encompasses any variant falling within the scope of the invention as defined by the claims.

[0070] We have described here that the thermal coupling between each heat sink and an electrical component is a direct contact via a metallic pin. The thermal coupling could also be indirect, for example, coupling via a thermally conductive, possibly elastic, component.

[0071] Although it has been described here that the first vent and the second vent extend inside the box, one or both vents could perfectly well extend outside the box, or partially inside and partially outside the box.

[0072] It is also possible that only one of the two vents extends horizontally, and that only one of the two vents extends vertically.

[0073] It has been noted that the internal and external heat sinks are arranged to cool the same electrical component. Of course, the internal heat sink can perfectly well cool one electrical component and the external heat sink a second. The second electrical component could, for example, be located on the same circuit board but on a different side, or on a different circuit board altogether.

[0074] The internal (and / or external) heat sink can, of course, cool not just one but several electrical components. The electrical component(s) thermally coupled to the internal (and / or external) heat sink do not necessarily belong to an audio amplifier: they can be any type of electrical component that heats up during operation, for example, a processor, a radio transmitter, etc.

[0075] The first vent can be located on any side of the enclosure. Preferably, the end of the first vent is located at the top to expel hot air. Similarly, the second vent can be located on any side of the enclosure. Preferably, the end of the second vent is located at the bottom to allow fresh air to enter.

[0076] It has been stated that the first vent is located near one end of the first face, that the second vent is located near a second end of the first face, and that the first end is a top end and the second end a bottom end. A different configuration is possible. For example, if the first face containing the speaker is a top face, the first end could be a left end and the second end a right end of the first face.

Claims

1. A loudspeaker enclosure of the bass reflex type comprising a cabinet (606), a loudspeaker, and a first vent (10; 110), a second vent (11; 111) and an internal heatsink (612) situated inside the cabinet and for being thermally coupled with a first electrical component in order to dissipate, inside the cabinet, heat produced by the first electrical component; the first vent, the second vent, and the internal heatsink being positioned in such a manner that a flow (F) of air passing through the first vent, the second vent, and inside the cabinet exhausts the heat produced by the first electrical component to outside the cabinet, characterized in that a plane surface of the internal heatsink (612) forms a portion of an outside wall of a face of the cabinet, the first vent and / or the second vent extending) at least in part within the internal heatsink.

2. A loudspeaker enclosure according to claim 1, wherein the first vent and / or the second vent extend(s) horizontally inside the cabinet.

3. A loudspeaker enclosure according to claim 1, wherein the first vent (610), the second vent (611), and the internal heatsink (612) form a single part.

4. A loudspeaker enclosure according to claim 1, wherein the internal heatsink (612) is a finned heatsink, and wherein each of the first and second vents extends between two fins (614) of the internal heatsink.

5. An acoustic device comprising a loudspeaker enclosure according to any preceding claim, and a printed circuit board (2; 102) on which the first electrical component is mounted.

6. An acoustic device according to claim 5, wherein the printed circuit board is situated inside the cabinet.

7. An acoustic device according to claim 5, wherein the printed circuit board is situated outside the cabinet.

8. An acoustic device according to claim 5, wherein the first electrical component forms part of an audio amplifier.

9. An acoustic device according to claim 5, further comprising an external heatsink (722) positioned outside the loudspeaker enclosure.

10. An acoustic device according to claim 9, the external heatsink being thermally coupled with a second electrical component.

11. An acoustic device according to claim 10, the second electrical component and the first electrical component being one and the same electrical component.

12. Electrical equipment comprising an acoustic device according to any one of claims 5 to 11.

13. Electrical equipment according to claim 12, the electrical equipment being a residential gateway or a set-top box or a TV set or a voice assistant.

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