JPH01264098A - Fluid type silencer for speaker - Google Patents

Abstract

PURPOSE:To obtain high quality sound by using a butterfly type diaphragm so as to change sound pressure into an air fluid force. CONSTITUTION:A diaphragm 1 is a butterfly diaphragm whose fulcrum is supported by an edge 2 with a small bending resistance, and with a sound pressure vibrating it occurred, a circular-arc vibration (a) is attended, an air flow is caused as (b) in figure toward the circumferential direction and flows in a direction nearly equal to a connection direction C. The diaphragm is formed by sectors being equal divisions of a disk, a slight gap (d) is provided so that the diaphragm sectors 1 are not contacted with each other and the diaphragm is supported by the edge 2 of the circumferential part. Through the constitution above, the air flow is concentrated as shown in (b) in the center and a fast flow velocity is obtained. Then high quality sound is obtained.

Description

[Detailed Description of the Invention] This invention relates to a sound deadening method that replaces sound absorption for speakers.In order to prevent sounds from the front and back of the speaker from interfering with each other, the speaker is generally housed in a cabinet etc. However, the bounce of the sound emitted by the speakers into the cabinet affects the speakers again, causing the sound quality to leak. For this reason, in the past, sound pressure applied to sound-absorbing materials such as glass wool and felt caused friction on the particles of the sound-absorbing material, which was converted into thermal energy and consumed. However, while trying to increase the sound absorption effect by putting a lot of sound-absorbing material inside the cabinet, the sound-absorbing material around the back of the speaker is included in the effective mass of the speaker's vibration system, resulting in a decrease in the electroacoustic conversion efficiency of the speaker, or a decrease in the speaker cone. The diaphragm tends to bend easily, which tends to lead to a decrease in volume and a lack of sense of presence.

In order to avoid these contradictory problems, the butterfly diaphragm converts the power of sound into the kinetic energy of flowing air, which is required to have a muffling effect down to the low range than before, and also increases the sensitivity of the speaker and achieves high quality. A unique sound is required.

To explain this invention based on the drawings, as shown in FIG. When sound pressure that causes vibration occurs, the airflow moves toward the circumference (b) with circular vibration as shown in (a).
The flow occurs in a direction approximately equal to the tangential direction (c). As shown in Figure 2, such a diaphragm is made into a circle divided into equal parts, with a slight gap (d) so that the triangular diaphragms (1) do not come into contact with each other, and edges (2) of the circumferential part. ) to support the diaphragm. By adopting such a shape, the airflow is concentrated in the center as shown in (b), and a high flow velocity can be obtained.

Figure 3 shows the implementation of types (A) and (B) of a speaker system consisting of a speaker (1) and a cabinet (2). Type (B) is a composite shield ring in which the diaphragms (3) and (3') are installed in opposite directions with the diaphragms (3) and (3') open to allow airflow (b) to flow in and out of the cabinet (2). It is a type.

The process of converting the force of sound into the kinetic force of the air is as shown in Figure 4, when sound normally travels through the air, one period of the sound (a
~b) does not give any motion to the air, so (A), (
B) It can be thought of as forces that are equally balanced in the air. When sound forces (A) and (B) are generated on the butterfly diaphragm (1) as shown in FIG. 5, the sound force is inclined in the direction of the centrifugal force (F) of the air.

In addition, in the method of tilting the force of sound, as shown in Figure 6, by applying airflow (a) with a fan motor (2), the speaker (1) can move the air in the opposite direction to the direction of the force (A) that pushes the air. The direction of the force (B) exerted by atmospheric pressure is
As shown in (A') and (B'), they are tilted in the same direction and the acting force (F) can be obtained. In this way, by tilting the force of sound, the balance of forces in the air is lost, and the sound is likely to be consumed as fluid force.

Figures 7 (A) to (D) show application examples of this invention (A
) and (B) types are composite shield-ring types that provide outflow and inflow airflow (a), while type (A) concentrates airflow (a) on the back of the speaker (1) using a partition plate (2). let me,
Furthermore, a fan motor (3) provides a constant flow rate at all times.

Types (C) and (D) are single spiral type, and types (B) and (
Type D) is suitable for applications in closed cabinets, and in particular for televisions and radios that do not have speaker cabinets.

The butterfly diaphragm is made of durable, lightweight material that does not easily bend, and by adjusting the area, it is relatively smaller than conventional cabinets, and it is easy to obtain straightforward characteristics without using sound-absorbing materials. Like a general bass reflex type cabinet, the frequency impedance characteristics have two peaks,
The lowest point between the peaks almost matches the speaker's declared impedance, but with the flow conversion formula, the impedance decreases considerably in the frequency range from the peaks of the impedance due to the reduction in acoustic resistance due to the flow conversion. A characteristic feature is that it is increasing.

As described above, since it makes it easier to apply force to the air on the back of the speaker in a fixed direction, it has the effect of reducing acceleration resistance compared to the reciprocating load of the air, and it also reduces the deformation of the cone. It is required to reduce cross-modulation distortion, and it is possible to obtain sound quality with good sensitivity and less turbidity.

4. Brief Description of the Figures In FIGS. 1 and 2, (B) is a slope sectional view, and (A) is a sectional view.

Figure 3 is a cross-sectional view FIG. 4, FIG. 5, and FIG. 6 are explanatory diagrams of the operating state.

FIG. 7 is a sectional view showing the application row.

Claims (2)

[Claims] (1) A fluid silencer for a speaker that converts sound pressure into air flow force through butterfly-type vibration that vibrates in an arc around a fulcrum in response to the sound pressure of the speaker. (2) The fluid-type silencer for a speaker according to item 1, which provides an airflow from a fan motor to the rear surface of the speaker and tilts the direction of the sound force.