EP4200165A1

EP4200165A1 - Subwoofer

Info

Publication number: EP4200165A1
Application number: EP21739370.1A
Authority: EP
Inventors: Christophe Parcellier
Original assignee: Renault SAS
Current assignee: Renault SAS
Priority date: 2020-08-18
Filing date: 2021-07-05
Publication date: 2023-06-28
Also published as: FR3113475A1; WO2022037837A1; FR3113475B1

Abstract

The invention relates to a low frequency subwoofer, characterized in that said subwoofer comprises at least two loudspeakers and a vent, in particular of laminar type, said subwoofer having at least two vent inlet mouths and a vent outlet mouth.

Description

Title of the invention: SUBWOOFER

The invention relates to a subwoofer. It finds an advantageous application in the form of a motor vehicle equipped with such a box.

We know the document CN202138311 U concerning a vehicle having a box positioned in the rear part of the central console and comprising a single loudspeaker, but this box architecture, located in the center along the lateral axis Y of the vehicle, radiates outward. back and therefore has no impact on the front performance.

We also know the document JP20102150742 in which are described two boxes independent of each other with a tubular bass reflex vent in each box, however each vent opens into the feet of the occupants which is almost prohibitive for acoustic neutrality and the comfort on board due to the mouth noise, that is to say the breath of air generated by this vent. In addition, this solution is expensive because it requires two independent boxes and it does not allow the loudspeakers to operate in a "push-pull" solution, that is to say that the loudspeakers both move in the same direction, or "push-push", that is to say that the loudspeakers move in opposite directions, depending on the desired performance. In addition, two independent boxes can operate differently acoustically and electrically speaking, which can constitute a risk of acoustic instability.

One of the aims of the invention is to remedy at least some of the drawbacks of the prior art by providing a subwoofer which makes it possible to increase the power performance of the loudspeakers without increasing the noise and by reducing the size of the speakers. To this end, the invention proposes a low-frequency box comprising at least two loudspeakers and a vent, said box comprising at least two inlet mouths, two of which correspond to the locations of two of the at least two loudspeakers and one vent outlet mouth. Thanks to the invention, there is a compact box with optimized acoustic performance.

According to an advantageous characteristic, the vent is of the laminar type, which makes it possible to reduce muzzle noises compared to a tubular vent.

According to another advantageous characteristic, the two loudspeakers are identical, in particular of at least one hundred and ten millimeters in diameter and/or at most one hundred and fifty millimeters in diameter, which avoids acoustic differences while occupying a volume reduced by compared to traditional premium mounts.

According to another advantageous characteristic, the section of the vent is constant along the vent, which makes it possible to have no slowing down or local acceleration of the air speed which could cause acoustic inconvenience.

The advantage of the characteristic that the vent has a single outlet mouth is to allow the air here to exit forwards and not towards the feet of the occupants, for more comfort.

According to another advantageous characteristic, the outlet mouthpiece is of rectangular section, which makes it possible to reduce mouth noise.

Advantageously, the corners AA of the openings of the vent, and preferably all along the vent, are rounded, so as to avoid hissing.

According to another advantageous characteristic, the laminar vent has a height greater than eighteen millimeters, which allows for a vent length of 130 millimeters not to generate acoustic discomfort.

According to another advantageous characteristic, the vent has a constant length to section ratio along the vent, thus guaranteeing the electroacoustic performance. The invention also relates to a central console of a motor vehicle, comprising a low-frequency box according to the invention, said console comprising a sound-guide flange over 360 degrees completely surrounding a circumference of each loudspeaker on which it is centered. , which has advantages similar to those of the box and allowing better guidance of the sound.

The invention also relates to a motor vehicle comprising a passenger compartment, the vehicle comprising a central console according to the invention, said passenger compartment comprising at least two front seats separated from each other by at least a part of the console, each seat forming on each side of said part of the console with a front end of the passenger compartment a space, at least two of said loudspeakers of the box each being oriented towards one of said spaces, which has advantages similar to those of the console and making it possible to improve the acoustic quality at the front.

According to another advantageous characteristic, the two inlet mouths of the vent corresponding to the locations of two loudspeakers are each oriented towards one of said spaces and the outlet mouth of the vent opens towards the front of the vehicle, this which allows for increased comfort for the driver and front passenger.

The advantage linked to the characteristic according to which the box is located under said part of the central console between said seats is the compactness of the assembly, while having improved performance due to the central location while guaranteeing comfort by absence of muzzle noise in the driver's or front passenger's feet.

According to another advantageous feature, the console includes a side grille covering each loudspeaker, which makes it possible to protect each loudspeaker membrane from possible intrusions.

Other characteristics and advantages will appear on reading a preferred embodiment described with reference to the figures in which:

[Fig.1] Figure 1 shows a front view of a compliant subwoofer to the invention, and,

[Fig. 2] Figure 2 shows a three-quarter view of a subwoofer according to the invention, and,

[Fig. 3] Figure 3 shows an example of a method of fixing a subwoofer according to the invention, and,

[Fig. 4A] FIG. 4A represents a view of the subwoofer in accordance with the invention, installed in the center console in its vehicle environment, and,

[Fig. 4B] figure 4B shows a detail view of the previous figure without visible central console, and,

[Fig. 5] Figure 5 shows a sectional view of the box and console assembly.

Throughout the text, the directions and orientations are designated with reference to a direct orthonormal reference XYZ conventionally used in automotive design, in which X designates the longitudinal direction of the vehicle, directed forwards, Y is the direction transverse to the vehicle, pointing left and Z is the vertical direction pointing up. The notions “front” and “rear” are indicated with reference to the normal direction of travel towards the front of the vehicle. Throughout the description, the term "substantially" means that a slight deviation can be allowed with respect to a determined nominal position or orientation, for example "substantially vertical" means that a deviation of the order of 5° from relative to a strictly vertical orientation is accepted within the scope of the invention. For greater clarity, identical or similar elements are identified by identical reference signs in all the figures.

According to a first embodiment of the invention shown in Figures 1 and 2, the CBF subwoofer is preferably made of plastic material (PP, PE, ABS) with an additional filler (Talc, fiberglass, etc. ). In order to increase the acoustic performance of the CBF subwoofer with less voltage at the loudspeaker terminals, the latter comprises a vent, that is to say a duct allowing the circulation of air. Specifically here this EL vent is of the laminar type, that is to say of rectangular section, whose outlet mouth is directed towards the front of the vehicle, and the side front mouths of the EL vent correspond to the locations of the two high- speakers fitted to the CBF box, one of which radiates into the driver's feet and the other into the passenger's feet. The advantage of this laminar EL vent, and more specifically of its rectangular and non-circular CEE inlet mouth contour, with iso section, is to reduce mouth noise. Advantageously, the laminar vent EL over its entire length L is rectangular in shape, which allows better fluidity of the air and good speed, while also improving feasibility. This rectangular shape of the duct has less perceived muzzle noise than a circular vent. The dimensioning of the section depends on the expected performance in a given frequency range. Furthermore, it is preferable for its height H not to be less than 18 to 20 millimeters to avoid the creation of muzzle noise. As long as the section remains constant from the beginning to the end of the vent, the height H can then vary along the vent, and in particular shrink while maintaining the passage section constant, nevertheless it is preferable not to modify its height. The constant section along the vent makes it possible not to modify the speed of the air flow, which could create noise annoyances. The width of the vent is in this example here 130 millimeters due to the desired performance. Preferably, the CEE inlet and CES outlet mouth contours are rounded at the corner breaks so as to reduce acoustic noise and more specifically to avoid whistling. It is the same all along the vent.

The dimensioning characteristics of the vent EL, in particular its length L of the duct and section S equal to the product of the length of section Ls by the height H of the duct, are defined according to the desired electroacoustic parameters. The height of the outlet mouth CES of the vent must not be less than 1/7 of the section length Ls of the vent EL, thus with a vent of 130 millimeters in section length Ls, the height H of the outlet mouth must not be less than 18 millimeters. Are thus defined the values of section length Ls and height H and the formula Length/Section L/S must be constant whatever the shape of the laminar vent (rectangular/square), or tubular (circular), the section S of the vent conditioning the speed of the airflow. The shape of the vent can indeed be conditioned by the implantation zone and in fact by the shape and the implantation of the box. The two loudspeakers are identical and are here 130 millimeters in diameter.

As shown in Figure 3 in this view of the CBF box, the vent inlets correspond to the locations of the two loudspeakers (only one visible in this figure). The CBF box here comprises four fixing lugs PF positioned on the lateral sides of the CBF box, including two at the top at the front of the CBF box and two at the rear at the bottom of the CBF box, and the fixing of the lugs is carried out by a set screw nut. This method of fixing is in no way limiting, but purely indicative.

As shown in Figures 4A and 4B, the box CBF is located at Y0, that is to say in the center along the Y axis of the vehicle, and here corresponding to the center of the vehicle in the front zone at the level of the central console CC , and represented in its vehicle environment. The CBF box is fixed to the floor of the PV vehicle using fixing lugs, which are at least 3 in number. The CBF box is located under the part of the center console, or its trim, separating the driver and front passenger seats. The central console CC is positioned above the CBF box during factory assembly. In this CC console, two grids (not shown) are integrated to allow the sound of the loudspeakers of the subwoofer to be diffused. The grids preferably have permeabilities of at least 30%. Alternatively, the box could be directly integrated into the central console, but it would then be necessary to ensure the rigidity of the assembly and the absence of parasitic vibration on the various elements of the console. The fact of decoupling the box and the console makes it possible to avoid these risks. As shown in the sectional view of FIG. 5, a CGS sound guide collar is added to the CBF subwoofer - CC console assembly. In FIG. 5, the loudspeaker HP is represented at rest. Preferably, this CGS collar is molded or glued to the console (or to its covering) CC. It is preferably made of a composite material, in particular of a matrix such as polyamide, polypropylene, or polyethylene, and in particular of the same material as the central console. Alternatively, this CGS flange can be integrated by molding into the CBF box. The function of this CGS flange is to guide the frequencies in an optimized manner. This 360-degree CGS sound-guiding bezel is centered on the HP speakers and completely surrounds the circumference of each HP speaker. As shown, the CGS collar comes at a maximum distance Dcgs_hp of 6 millimeters from the loudspeaker HP, preferably a maximum of 5 millimeters, in order to avoid problems of sound leakage between the box and the console. To alleviate this sizing constraint, a foam can also be added to close the volume. The thickness of the flange can be of the order of 2 millimeters or more, preferably up to the material thickness of the console +/- 15%, and its height from 10 to 20 millimeters, preferably 15 millimeters. At rest, the grille G is located at a distance Dg_hp from the cone of the loudspeaker HP of between 11 and 20 millimeters, the distance Dg_hp being measured at the end of the cone closest to the grille G.

As a variant, a third passive loudspeaker could be added to the two loudspeakers of the CBF box, that is to say consisting only of a membrane and a basket, facing the rear of the vehicle in order to improve performance in terms of sound pressure.

Thanks to this embodiment, it is thus possible to replace a system with two loudspeakers 165 millimeters in diameter, one per lower volume of each door trim, by this subwoofer located under the center console. This unique box equipped with 2 loudspeakers 130 millimeters in diameter, radiating for the left loudspeaker in the driver's footwells and in the passenger footwells for the right loudspeaker, provides an available sound amplification of 15W compared to the previous system and allows to have under a pink noise signal (standard signal used to make the frequency response curves) at - 23dBFS a value of 105dB maximum between 80Hz and 100Hz in the car which corresponds to the value obtained with the 165millimeter speakers from the previous system. In addition, this box makes it possible to completely free up the lower volume in the door trims for all levels of the audio range without having to redo the door panels. Only a small 100 millimeter loudspeaker fixed at the top of the door is added, and this throughout the range. Indeed, very often car manufacturers have a Premium audio system with small speakers (that is to say with a diameter less than about 110 millimeters) in the doors and subwoofers in the passenger compartment but in the in the case of their standard mount, they must reserve a volume to put a 165 mm loudspeaker at the bottom of the door. This obliges them either not to put a 165 mm loudspeaker at the bottom of the Premium doors or to undergo a diversity of door panels with on the one hand a specific door panel without loudspeaker as standard and a panel specific door with allocation of a volume in the lower part of the door trim, with all the logistical, practical and economic disadvantages that the diversity of the room imposes. Thanks to the invention, this box is available for all the audio versions, arranged at Y0 of the vehicle, and a single door panel is made for the entire upgrade in audio and interior finish.

Claims

9 CLAIMS

1. Low-frequency box (CBF) of a motor vehicle, characterized in that said box (CBF) comprises at least two loudspeakers (HP) and a vent (EL), said box (CBF) comprising at least two mouths of entry (CEE), two of which correspond to the locations of two of the at least two loudspeakers (HP) and an outlet mouth (CES) for the vent.

2. Motor vehicle low-frequency box (CBF) according to claim 1, characterized in that the vent (EL) is of the laminar type.

3. Motor vehicle low-frequency box (CBF) according to any one of the preceding claims, characterized in that the two loudspeakers (HP) are identical.

4. Motor vehicle low-frequency box (CBF) according to any one of the preceding claims, characterized in that the section (S) of the vent (EL) is constant along the vent (EL).

5. Motor vehicle low-frequency box (CBF) according to any one of the preceding claims, characterized in that the vent (EL) has a single outlet mouth (CES).

6. Motor vehicle low-frequency box (CBF) according to the preceding claim, characterized in that the outlet mouth is of rectangular section.

7. Motor vehicle low-frequency box (CBF) according to any one of the preceding claims, characterized in that the vent (EL) has a constant length (L) to section (S) ratio along the vent.

8. Center console (CC) of a motor vehicle, characterized in that it comprises a low-frequency box (CBF) according to any one of the preceding claims, said console (CC) comprising a sound guide flange (CGS ) over 360 degrees completely surrounding a circumference of each loudspeaker (HP) on which it is centered.

9. Motor vehicle comprising a passenger compartment, characterized in that it comprises a central console (CC) according to the preceding claim, said passenger compartment comprising at least two front seats separated from each other by at least a part of the console (CC), each seat forming on each side of said part of the console (CC) with a front end of the passenger compartment a space, at least two of said loudspeakers (HP) of the box (CBF) each being oriented towards one of said spaces.

10. Motor vehicle according to the preceding claim, characterized in that two inlet mouths (CEE) of the vent (EL) corresponding to the locations of two loudspeakers (HP) are each oriented towards one of said spaces and in that the The outlet outlet (CES) of the vent opens towards the front of the vehicle.

11 . Motor vehicle according to any one of Claims 9, 10, characterized in that the box (CBF) is located under the said part of the central console (CC) between the said seats.

12. Motor vehicle according to any one of claims 9 to 11 characterized in that the console (CC) comprises a side grid (G) covering each loudspeaker (HP).