MXPA99010500A - Panel-form loudspeakers - Google Patents

Abstract

A panel-form loudspeaker comprises at least two resonant distributed mode acoustic panels with a single driver provided to excite all the panels such that bending wave energy is efficiently transferred to each of them to excite distributed mode resonance in them to provide acoustic output. There may be two panels one larger than the other - the larger having a lower bending wave stiffness than the smaller. The smaller panel is positioned eccentrically of the larger and the driver eccentrically of the smaller panel. A plurality of smaller panels may be associated with a single larger panel. One embodiment provides a driver mounted to the or each smaller panel which is adhesively attached face to face to the larger panel. Another embodiment provides the or each smaller panel formed within and attached to the larger panel, a driver being attached to the or each smaller panel. The attachment of the panels uses a material forming a controlling compliant coupling. A third embodiment provides the or each smaller panel mounted on one end of an associated coupler passing through and attached to the larger panel, a driver being attached to the other end of the or each coupler. The attachment of the or each coupler to the larger panel uses a material forming a controlling compliance coupling. The or each coupler is tubular in section.

Description

BACKGROUND IN THE FORM OF A PANEL FIELD OF THE INVENTION The invention relates to loudspeakers in the form of a panel, and more particularly, although not exclusively, to loudspeakers in the form of a panel of the type described in our International Application O97 / 09842 and known as loudspeakers. in a distributed way. BACKGROUND OF THE ART In theory and given the availability of appropriate materials, a distributed mode loudspeaker can cover the entire "" range of audio frequencies in a single panel. Given that the current state of the art in terms of material technology does not allow such a solution, our International Application O / 9709846 contemplates small loudspeaker panels of distributed mode suspended in a loudspeaker panel of distributed mode of larger size, with a more frequent cutting frequency. low, to produce a loudspeaker with a greater acoustic bandwidth. This requires at least two impellers of the appropriate type and also requires a careful design of the mechanical interface between the two panels. Since both panels cover a wide range of frequencies within their individual capacities, there will also be a wide range of frequencies within which the outputs of the two panels could be superimposed. Therefore, an electric filter network may be desirable, although it may tend to degrade sound quality and increase manufacturing costs. An object of the invention is to provide facilities that improve or overcome these difficulties. GENERAL ASPECTS OF THE INVENTION In one aspect, the invention provides a loudspeaker in the form of a panel comprising at least two resonant acoustic panels in a distributed manner, in which a single impeller is supplied to drive all the panels, so that the energy of The bending waves are transferred efficiently to each of them to excite the resonance so distributed in them in order to produce the acoustic output. The desirable thing is that there are two panels and one such panel can be larger than the other. The largest of such panels preferably has a lower stiffness of the bending wave than the smaller one.

The smaller of such panels is conveniently placed eccentrically with respect to the larger panel. It is desirable that the impeller is positioned eccentrically with respect to the smaller of such panels. In one embodiment, a plurality of minor panels are associated with a single major panel. The advantage is that an impeller is mounted on the one or each of the smaller panels joined to the larger panel, such a connection being made so that the energy of the bending waves of the or each impeller and its associated smaller panel is transferred in the form efficient to the larger panel. Preferably, the smaller and larger panels are joined face to face. The panels can be secured to each other by means of a low mechanical loss adhesive. In another embodiment the or each of the minor panels are formed inside and are joined to the larger panel, and an impeller is attached to the or each smaller panel. The joint of the smaller and larger panels can be made with a material that forms an elastic control coupling.

- In another mode, the or each of the smaller panels is mounted on a_. end of an associated coupler that traverses and is joined to the larger panel, with an impeller attached to or to each of said couplers. The impeller (s) is preferably attached to the other end of the or each coupler. It is desirable that the union of the or each coupler to the larger panel makes use of a material forming an elastic control coupling. The or each coupler is preferably of tubular section. BRIEF DESCRIPTION OF THE DRAWINGS The aspects, features and advantages of the invention indicated above will become apparent from the following description of the embodiments of the invention now made with reference to the attached drawings, in which: Figure 1 shows in A and B respectively, rear and side views of a first panel loudspeaker incorporating the invention. Figure 2 is a sectional side view of a second panel loudspeaker incorporating the invention.

Figure 3 is a sectional side view of a third panel loudspeaker incorporating the present invention; and Figure 4 is a rear side view of a modified form of the loudspeakers shown in Figures 1 to 3. BEST MODES FOR CARRYING OUT THE INVENTION Figure 1 shows a smaller distributed-mode loudspeaker panel (10) driven by an appropriate impeller or driver (12), preferably of the electrodynamic type for a greater bandwidth. The smaller panel (10) is attached face-to-face to a larger-size distributed loudspeaker panel (14) of appropriately smaller stiffness and of adequate dimensions to cover the required lower frequency range. Choosing the appropriate exciter materials and design to show that when excited the smaller panel (10) will continue to produce its useful bandwidth superimposed upon. the lower range frequency output resulting from the larger panel (14) giving a much larger bandwidth. The smaller size distributed loudspeaker panel (10) can be attached to the larger panel by applying appropriate adhesives of low mechanical loss to maintain efficient mechanical energy transfer at low frequencies, while also maintaining good high frequency transmissibility with little loss Epoxy resin adhesives are suitable for this purpose. The joining position of the smaller panel (10) to the larger panel (14) will be chosen in accordance with the principle of distributed mode as explained in our International Application O / 97/09842, as well as the position of union of the exciter ( 12) to the minor panel (10). Figure 2 illustrates another type of panel-shaped loudspeaker-incorporating the invention, in which an optimized panel of distributed low-frequency mode of larger size (20) is modified, making a smaller high-frequency optimized panel (22) is formed in the region of an exciter (24). The common excitation point of the exciter (24) means that both parts or regions of the panel are excited. The high frequency portion or region of the panel, which is smaller in size, is provided by an additional reinforcement of the stiffness of the local surface region (26), for example, by adding bonded carbon fiber, glass fiber or a similar material high strength Alternatively, adding new surface sections of higher stiffness in that region. Depending on the wave propagation properties of the major panel (20) a natural balance of power splitting can be obtained with frequency. Additionally, an appropriate elasticity limit (28) is incorporated to differentiate between the higher and lower frequency parts of the panel. The control of the damping dependent on the elasticity frequency of the flexible coupling makes it possible to determine the ideal or preferred filter point mechanically, together with a beneficial control of the damping in the boundary between the two parts of the panel. Figure 3 illustrates another type of loudspeaker in the form of a panel incorporating the invention. In the installation of Figure 3 a smaller high frequency panel (30) is fixed by adhesives to one end of a lightweight tubular coupler (32). The coupler passes through a larger low frequency panel (34) and joins it flexibly as shown in (36). The flexible connection "from the coupler to the larger panel (34) acts as a mechanical low pass filter to further define the energy balance between the two panels (30 and 34). It can be seen that the end of the coupler (32) separated from the panel high frequency (30) is fixed to a driver exciter (38) A further installation incorporating the invention is illustrated in Figure 4, where a large single-mode resonant acoustic panel (50) is associated with a series of panels smaller (52) each with an associated exciter (54) The smaller panels (52) may be associated with the larger panel (50) in the ways described with reference to figures 1 to 3. That is, that the smaller panel (52) can be attached by face-to-face adhesive with the larger panel (50) and be mounted to its own exciter (54). Alternatively, the smaller panels (52) may constitute a number of sections of the larger panel (50) that have been duly reinforced in their stiffness and provided with an individual driver (54), the sections of reinforced stiffness (52") joining the panel greater in the manner described with reference to Figure 2. Finally, the smaller panels (52) may constitute panels carried by the couplers each associated with an individual driver in the manner described with reference to Figure 3. It will be appreciated that The smaller panels (52) in the installation of Figure 4 do not all have to be associated with the larger panel (50) in the same way Some could be associated in the manner described with reference to Figure 1 while others they are associated in the manner described with reference to figures 2 and / or 3. In the embodiments described, the exciter is attached or coupled in each case to a smaller panel. to go united or coupled to the largest of the panels if desired. INDUSTRIAL APPLICABILITY The described distributed mode loudspeakers have the benefits of allowing a total audio-frequency bandwidth in a single loudspeaker and reducing the number of exciters required and therefore the cost and complexity of the loudspeakers. A loudspeaker according to the present invention can be applied on the board of a. automotive, with the benefit of a reduced number of components, which will result in greater reliability, avoid electrical filter components and involve lower manufacturing costs.

Claims (15)

1. NOVELTY OF THE INVENTION Having described the present invention is considered as a novelty and therefore the content of the following claims is claimed as property. - - 1. A loudspeaker in the form of a panel comprising at least two resonant acoustic panels of bending wave in a distributed manner, characterized in that it includes a larger panel and a smaller panel, wherein both the major and minor panels are excited by a single exciter installed in such a way that the energy of the bending waves is transferred to both panels the largest and the least to excite the distributed mode resonance in the major and minor panels in order to provide the acoustic output.
2. 2. A loudspeaker in the form of a panel according to claim 1, characterized in that the larger panel has a lower bending wave rigidity than the smaller panel.
3. 3. A loudspeaker in the form of a panel according to claim 1 or claim 2, characterized in that the minor panel is placed eccentrically with respect to the larger panel.
4. A loudspeaker in the form of a panel according to any of the preceding claims, characterized in that the exciter is positioned eccentrically with respect to the smaller of such panels.
5. 5. A loudspeaker in "panel form" according to claim 1, characterized in that it has additional small panels, each having an associated exciter installed in such a way that the energy of the bending waves is transferred efficiently to both minor panels associated with the exciter and the larger panel to excite the resonance of distributed mode in the panels to provide the acoustic output.
6. 6. A loudspeaker in the form of a panel according to claim 1, characterized in that there are exactly two panels.
7. 7. A loudspeaker in the form of a panel according to any of claims 1 to 5, characterized in that a driver is mounted on, or in each of the smaller panels that are joined to the larger panel, the connection being such that the power of the bending waves of, or of each exciter and its associated minor panel is efficiently transferred to the larger panel.
8. 8. A loudspeaker in the form of a panel - according to claim 7, characterized in that the or each of the smaller panels is joined to the larger panel face to face.
9. 9. A loudspeaker in the form of a panel according to claim 7 or claim 8, characterized in that the panels are secured to one another by means of an adhesive with low mechanical loss.
10. A loudspeaker in the form of a panel as claimed in any of claims 1 to 6, characterized in that the or each of the smaller panels is formed inside and is joined to the larger panel, an exciter being attached to each one of the minor panels.
11. 11. A loudspeaker in the form of a panel according to claim 10, characterized in that the joining of the smaller and larger panels is carried out with a material forming an elastic control coupling.
12. 12. A loudspeaker in the form of a panel as claimed in any of claims 1 to 6, characterized in that it comprises a coupler that passes through and joins the larger panel, the smaller panel being mounted at one end of the coupler and the exciter associated with the smaller panel being attached to drive the coupler.
13. A loudspeaker in the form of a panel according to claim 12., characterized in that the exciter is joined to the end of the coupler opposite the end attached to the corresponding minor panel.
14. 14. A loudspeaker in the form of a panel according to claim 12 or claim 13, characterized in that the coupling of the coupler to the larger panel makes use of a material forming an elastic control coupling.
15. 15. A loudspeaker in the form of a panel according to any of claims 12 to 14, characterized in that the coupler is of tubular section. SUMMARY A loudspeaker in the form of a panel comprises at least two resonant acoustic panels in a distributed way with a single exciter provided to excite all the panels in such a way that the energy of the reflection waves is efficiently transferred to each one of them., to excite the resonance of distributed mode in them and provide the acoustic output. There may be two panels, one larger than the other, with the larger one having less flexural rigidity than the smaller one. The minor panel is positioned eccentrically with respect to the major panel and the exciter eccentrically with respect to the minor panel. A plurality of minor panels may be associated with a single major panel. One embodiment of the invention provides an exciter mounted on the or each smaller panel, bonded by face-to-face adhesive with the major panel. Another embodiment of the invention provides the or each smaller panel formed within the major panel and attached thereto, with an exciter attached to each smaller panel. At the junction of the panels, a material is used that forms an elastic control coupling. A third embodiment of the invention - provides the each smaller panel mounted at one end of an associated coupler that passes through and is attached to the larger panel, with an exciter attached to the other end of the or each coupler. In the union of the or of each coupler to the larger panel a material is used that forms an elastic control coupling. The or each coupler is of tubular section.