DE2927848C2 - Loudspeaker with reusable membrane - Google Patents

Description

The invention relates to a spring arrangement which stabilizes a reusable diaphragm in its axis of oscillation serL

purpose

The invention is intended to prevent tumbling and tumbling movements of the reusable membrane elements that lead to ίο distortion of the acoustic signal.

State of the art

As already known, the vibration of a membrane along an axis can be stabilized by that the membrane is suspended in two spring levels. For ordinary one-way speakers, these are Both spring levels a spring that attaches to the outside of the membrane and also the shape of a rubber sink and a centering spring that attaches to the transition between the diaphragm and the drive coil. Both known designs of reusable diaphragms also sets this centering spring either on the first one or second membrane element (sources: A. B. Cohen / »HiFi-Loudspeakers and Enclosuresw / Verlag:

John F. Rider Publisher inc. New York / printed: 1956 pp. 44-47 // A. B. Cohen / Mechanical Crossover Characteristics in Dual Diaphragm Loudspeakers / Journal of Audio Engineering Society / Volume 5, January 1957, Number I).

s ° Control arrangements for electronic deflection control of reusable membranes are not yet known.

Criticism of the state of the art

In the known constructions of a reusable diaphragm there is a second spring level only in some cases as a centering spring either on the spool neck or on the outermost diaphragm element, while the remaining diaphragm elements are only suspended in one spring level. This has ^T rudel- and tumbling movements of the membrane elements result which manifest themselves as distortions of the acoustic signal.

The centering spring on the spool neck, which competes with the coupling springs, also results in a Amplitude modulation, because it decouples pulse components from the mechanical pulse onto the loudspeaker frame, which are lost to radiation.

The problem of damping mechanical overshoots of the membrane elements is only one Construction has been taken into account: Figs. 8A and 8B in the article by A. B. Cohen ("Journal of the Audio Engineering Society «- see above). In this case, however, the damping element takes directly on the coupling process part. In this way, the entire energy to be further coupled is delayed in time and, as a result, becomes a phase distortion.

Another problem with mechanical coupling via a spring arises from the conventional one Shape of feathers. Their usually sawtooth-shaped cross-sectional shape results in different repulsive forces Forces in the two directions of movement of the membrane, because each sawtooth flank is only in the Springs in the direction in which it is bent, so that the part of the spring which is in the one direction of movement acts, has a different tangential spring width or a different circumferential integral than the other.

This criticism applies mutatis mutandis to rectangular or trapezoidal cross-sections. Only with uniform

Curved cross-section, as it has so far only been used in dome tweeters, results in this respect an improvement than at least stretching is also possible in the resilient zones. It is However, it should be borne in mind that these springs »have a widening in the radial direction. So is a Symmetry, which is still given in the radial cross-section, no longer exists in the usual ring shape. In practice, the spring constant decreases in the radial direction towards the center point.

task

The invention aims to

—A dynamic stabilization of a reusable membrane against tumbling and tumbling movements without Effect decoupling of impulse components.

solution

The object is achieved by the features characterized in patent claim 1.

Advantageous embodiments of the invention

The coupling springs have a according to A b b. 3 designed Cross-sectional geometry. The change in the cross-sectional thickness in the radial direction causes a cancellation the radial change in the spring constant caused by the radial widening of the springs.

A mechanical overshoot is caused by damping elements according to A b b. 4 prevented. These elements are either on the springs or are ~, I at a short distance from them, but are always only with connected to the supports to be coupled. The aim of the practical implementation must be that the damping elements affect the coupling itself as little as possible. flow, but mechanically decouple the high frequency components generated by overshoot and filter away.

Electronic control of the reusable diaphragm is achieved by having actual value transmitters on the supports are attached, their signal sizes in the same proportion like the radiating surfaces of the membrane elements. Is a prerequisite for functioning No interference of the reusable membrane. By varying the signal size ratios and changes Ί5 Any expansion, compression or amplitude limitation can also be set. Basically all known actual value transmitter constructions are suitable for controlling a reusable diaphragm.

Embodiment,
represented by fig.

until 5

The reusable spring (seen from the side in A b b. I) consists of the supports (1, 2, 3) and the coupling springs (10, 11, 12). The reusable spring element (1, 10) the high frequency membrane element (4), the reusable spring element (2, 11) the mid-range membrane element (5) and Reusable spring element (3, 12) assigned to the Baßmembranele element (6).

Fig. 2 shows the reusable spring> n deflection direction seen. Each of the two reusable spring elements (2, 11 and 3, 12) consists of three supports and three semicircular coupling springs, the multi-way fiber element (1, 10) consists of a support and a concentric coupling spring. The reusable spring elements contain fine, rigid connections between the supports and coupling springs belonging to the respective element.

The coupling springs have a cross-sectional shape, as in A b b. 3 shown for the spring (2).

A b b. 4 shows the damping elements (34) in section, which are attached to all coupling springs and for example consist of a mixture of rubber and asbestos fibers.

A b b. 5 shows an actual value transmitter for optoelectronic actual value display. It consists of a template with triangular openings which are penetrated by light in the field (33) when they are in horizontal position Direction are deflected. The left opening is the modulator of the light transmitter when the membrane is in is deflected in the positive direction, and the right opening of the modulator when the membrane is in is deflected in the negative direction from the zero position. The zero position is shown. Light transmitter and receiver are rigidly connected to the loudspeaker frame.

Each of the three multi-way spring elements contains such an actual value transmitter. The adaptation to the radiating surface the reusable membrane elements are done by changing the acute opening angle of the triangular openings, but can also be done by changing the amount of light passing through the surface (33) or the Receiver sensitivity can be achieved. An addition of the signal quantities finally gives the measure for the electronic regulation.

List of reference symbols
to the A b b. 1 to 5

1,2,3 Supports between membrane elements and reusable spring

4 1st way: tweeter membrane element

5 2nd way: midrange membrane element

6 3rd way: middle of low tone or bass membrane element

7 1st way: Tweeter spring of the reusable membrane

8 2nd way: mid-range spring of the reusable diaphragm

9 3rd way: mid-bass or bass spring of the reusable membrane

10 1st way: Tweeter of the reusable spring

11 2nd way: mid-range spring of the reusable spring

12 3rd way: mid-bass or mid-bass spring of the multi-way spring

13 Loudspeaker basket, in solidarity with the housing

14 drive coil

32 optical actual value encoders

33 Light opening of the light guide channels

34 Cushioning

For this purpose 3 sheets of drawings

Claims (4)

Patent claims: 1. Loudspeaker with reusable membrane that - in the front edge of a loudspeaker basket (13) is suspended by the spring (9), - is driven by a plunger coil (14), - made of concentric membrane elements (4,5,6) is composed, which are connected to one another by the coupling springs (7,8), - In which the various spring-mass elements (4, 5, 6, 7, 8, 9) in the manner of a mechanical crossover are coupled so that the high frequency membrane element (4) vibrates on its own and, at lower frequencies, the membrane elements (5, 6) located further outside vibrate are coupled, marked by - a reusable spring arrangement (1, 2, 3, 10, II, 12; Fig. 1,2), the - on the back of the speaker basket (13) is hung up - with the coupling springs (10,11,12) in one plane are stretched - and between the coupling springs (10, 11, 12) Attach supports (1,2,3), which are rigid with the respective membrane elements (4, 5, 6) are connected. 2. Loudspeaker according to claim 1, characterized by - a cross-sectional geometry of the coupling springs (10, 11, 12; Fig. 3) their thickness at the center the concentric springs increases. 3. Loudspeaker according to claim 1, characterized by - Damping elements (34; Fig.4), each in front of and behind the coupling springs (10, 11, 12) on the cinzukoppelnden supports (2, 3) and the Loudspeaker frame (13) are attached and either directly adjacent or with a gap to the coupling springs (10, 11, 12) are arranged. 4. Loudspeaker according to claim I, characterized by - optoelectronic actual value transmitter on one support of each reusable spring element (1, 10/2, 11 / 3.12; Fig. l) that - From an opaque template (32) with symmetrical light passage openings exist that - have the shape of isosceles triangles, the legs of which are straight or curved are, and the - have an area ratio to each other like those with them rigidly over the supports (1, 2, 3) connected membrane elements (4, 5, 6), the deflection of which is optoelectronic through rigid with the speaker basket (13) connected light transmitter and receiver on the opposite Ropes of the templates are measured in field (33), - where the sum of the received amounts of light is the measure for the electronic readjustment the diaphragm deflection via the plunger coil (14). field of use