DE2753790A1 - ELECTROACOUSTIC CONVERTER - Google Patents

Description

7 5 3 7 9 0

Electroacoustic converter

The invention relates to electroacoustic transducers, in particular those with a dome membrane in which a dome is attached is attached to a drive element of the transducer which executes a vibratory movement and serves as a sound emitter.

The vibrating membrane of a dome loudspeaker has a central arched area, which is supported by a likewise towering ring-shaped bead is surrounded, which in connection with the dome surface, the acoustic properties of the loudspeaker influenced. The loudspeaker is mounted in a chassis, which also has its own special radiation pattern with amplitude and phase response as a function of frequency, these values basically being dependent on the shading of different areas the speaker membrane depend on the chassis structure.

There are numerous forms of such shadowed dome speaker systems been proposed in which the tuning of the loudspeaker by special acoustic shading elements is achieved, for example in the form of multiple funnel-shaped screens for selective shading of the vibrating Membrane.

The object of the invention is to create a simple means for tuning a dome loudspeaker without having to do so acoustic modifications to common loudspeaker chassis would be required.

The invention is an electroacoustic transducer with a dome-shaped vibrating membrane that a central dome with a surrounding, ring-shaped,

80982 3/0834

1 7 b 3 7 9 n

towering bead or bead, the peripheral edge of which with a mounting plate is connected, the dome being contained in an opening of this mounting plate. This speaker also has a disc-shaped vote lenient, which on the mounting plate is supported and has a central opening which is smaller than the opening of the mounting plate and within which at least a part of the dome area of the membrane is located, so that the tuning element adjusts the directional beam characteristic of the transducer modified or shaded.

This shadowing of the membrane of the transducer according to the invention takes place by means of an extremely simple structure. By suitable choice of the shape of the opening in the tuning element, the shading of the converter can be determined. Furthermore, the tuning element themselves can easily be exchanged, so that acoustic modifications of already existing dome-shaped loudspeakers are possible are.

In one embodiment of the invention, the mounting plate is essentially circular, but the opening in it is not circular. For example, it may be desirable to have a to modify the existing dome loudspeaker in such a way that an asymmetrical shadowing of the loudspeaker is obtained by using the Selects the shape of the opening of the tuning element suitable. In a preferred practical embodiment of the invention that has Tuning element has an elongated shape with symmetry about two perpendicular axes.

The diaphragm of the transducer is preferably attached to a surface of the mounting plate, while the disc-shaped tuning element is attached to the opposite surface of the mounting plate. The tuning element can be made of metal, cardboard, paper or plastic material. The opening in it is preferably designed with smooth edges. In a preferred embodiment the opening in the tuning element is limited by a peripheral flange protruding towards the membrane.

H Π 9 0? 7 / η Π 3 /,

The use of the voting element described here is permitted acoustic modifications of existing dome speaker systems and enables the improvement of the efficacy wheel in desired frequency ranges, using an extremely simple structure.

The invention is explained below with reference to the schematic representations an exemplary embodiment explained in more detail. Show it:

1 shows a plan view of a dome loudspeaker according to an embodiment of the invention;

Fig. 2 is a cross-section along the line II-II in Fig. 1 and

3 shows, on an enlarged scale, a plan view of the tuning element, which is used in the loudspeaker according to FIGS.

Figures 1 and 2 illustrate an electroacoustic transducer with a Kalottenlautsorecher, which has a dome-shaped Has vibrating membrane 1, which with a central dome part 2 is essentially circular in cross-section (see the dashed line Line in Fig. 2) and an annular, upstanding bead 3 surrounding this part. At the circumference of the membrane is »surrounding the ring-shaped bead 3, a rigid mounting plate attached so that the dome 2 and the bead 3 are located within a circular opening 5 of the mounting plate 4. the Mounting plate 4 forms part of the loudspeaker chassis. The membrane 1 is attached to the rear surface of the mounting plate 4, so that the protruding bead 3 and the dome 2, which are convex to the front of the loudspeaker, through to the front the opening 5 in the mounting plate 4 protrude towards its front.

Now to the acoustic properties of the dome loudspeaker

809823/0834

1 7 ο 3 7 9 n

-G-

Change TO sees the Kr invention before a scheibenförmicres Abstinimeloruent 6 made of metal or hard paper, which is for example fixed with the aid of feature 7, on the front surface of the mounting plate 4, ie where the Mernbran-befestiqunn.sf IMche entqeaenoesetzten surface. The tuning element 6 is designed with a central element that is smaller than the opening 5 in the mounting plate 4, so that edge parts of the tuning element 6 cover parts of the rina-shaped peripheral bead 3 and the dome part 2 of the membrane 1 and shade these parts acoustically. The shaded parts of the loudspeaker diaphragm are of course determined by the shape of the opening S in the tuning element 6.

In the illustrated embodiment, the central opening has 8 in the tuning element 6 has a generally elongated shape and is symmetrical about two mutually perpendicular axes, so that the edge parts of the taper 6 on opposite sides Ends of the shorter axis of the opening 0 effectively shade the parts of the membrane 1 located underneath. The edges of the Central opening 8 in the tuning element 6 at opposite ends the longer axis of the opening are formed with round recesses 9 (Fig. 3), and the edges of the opening 8 converge against these recesses 9 at an angle of 90 °. These converging edges of the opening 8 adjoin corresponding ones Circular arcs 10, the radius of which is five times as large as that of the recesses 9, and the diameter between them Circular arcs 10 determine the minor axis of the opening 8. The tuning element shown in FIG. 3, its main axis of symmetry is determined by the corresponding recesses 9, has rectilinear edge parts which form part of each recess 9 define and merge smoothly into the arcs 10, and these edge parts converge at an angle of 30 °.

In a practical embodiment of the invention, the tuning element is 6 made of hard paper or cardboard with a thickness of 0.35 to 0.40 mm. When the voting element is off hard paper or cardboard must be used in practice

809823 / 0R34

a surface treatment can be made to any To remove fibers from the cut edges defining the opening 8.

In another embodiment, the tuning element 6 is made of aluminum or another rotatable light metal and designed with a continuous circumferential flange, which defines the opening 8 and projects inwardly towards the membrane 1. The element 6 can in its thickness to the Remove the edge flange: For example, the outer edge of the element 6 can inwardly towards the opening 8 at an angle of 8 ° relative to the flat inner edge, which touches the mounting plate 4, be beveled.

809823/0834

I e e r s e ι t e

Claims (8)

Claims 1) Electroacoustic transducer with a dome-shaped Vibration diaphragm, which is formed with a central dome part and a raised folded part that surrounds it in a ring shape is, furthermore with a mounting plate which is attached to a region of the membrane surrounding the annular folded part is, and with an opening of the mounting plate, within which the cap part is located, characterized that on the mounting plate (4) for modifying or shading the directional characteristic of the transducer a disk-shaped tuning element (6) is supported, the has a central opening (8) which is smaller than the opening (5) is the mounting plate, within which at least part of the spherical cap area (2) of the membrane (1) is located. 809823/0834 2) converter according to claim 1, characterized in that the opening (3) in the mounting plate (4) is essentially circular and that the opening (8) in the tuning element (6) is not circular. 3) converter according to claim 2, characterized in that the opening (8) in the tuning element (6) has an elongated shape with symmetry has around two perpendicular axes. 4) converter according to claim 3, characterized in that the elongated opening (8) in the tuning element (6) with rounded recesses (9) is formed at opposite ends of the longer axis of the opening, and that the edges of the opening towards converge on the recesses each at an angle of practically 90 °. 5) converter according to one of claims 1 to 4, characterized in that that the membrane (1) is attached to a surface of the mounting plate (4) and that the disc-shaped tuning element (6) is attached to the opposite surface of the mounting plate. 6) converter according to one of the preceding claims, characterized in that that the tuning element (6) is made of metal, cardboard, paper or plastic material and that the opening (8) in the tuning element (6) is limited by smooth edges. 7) converter according to one of the preceding claims, characterized in that that the opening (8) in the tuning element (6) is limited by a circumferential flange which extends inwards in the direction protrudes onto the membrane (1). 8) converter according to claim 7, characterized in that the tuning element has a beveled outer surface, such that the Thickness of the element decreases in the direction of the peripheral flange. 309823/0834