JPS63102597A - Speaker - Google Patents

Abstract

PURPOSE:To eliminate a low order resonance mode on a diaphragm, to widen a band having a piston action and to produce a flat sound pressure frequency characteristic by providing plural driving points at the diaphragm, weighting the size of the driving force of respective driving points and driving the above- mentioned diaphragm. CONSTITUTION:Control parts 12a-12d control respectively individually the driving force of respective voice coils 6a-6d. To filters 13a-13d, a prescribed current frequency characteristic obtained in order to give an output executing the weighting to the driving force of the diaphragm to respective control parts 12a-12d is inputted. Thus, by changing respectively the driving force to the diaphragm 2 by the voice coils 6a-6d, a second resonance mode is also eliminated regardless of a node driving in a free oscillation, and a speaker having a flat sound pressure frequency characteristic, in which the band giving a piston action to a diaphragm 2 is widened, is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a speaker for high-fidelity reproduction both indoors and outdoors.

2. Description of the Related Art Conventionally, when driving a diaphragm, attempts have been made to cause the diaphragm to perform a piston movement over a wider frequency range. As is well known, by determining the position of the node of the free vibration mode and driving that point with a driving force such as a voice coil, lower modes on the diaphragm can be erased and the band of piston motion can be expanded. was.

An example of the above-mentioned conventional speaker will be described below with full reference to the drawings.

FIG. 3 shows the configuration of a diaphragm of a speaker driven by a driving force. In Figure 3, 1 is 1772
The speaker box 2 of X1771XO-05772 is a diaphragm of 0.8 m x O, 3 m. Four magnetic circuits are attached to the diaphragm 2 at nodes of the second resonance mode obtained by free vibration analysis. The magnetic circuit includes magnets 3a, 3b, 3c, 3d and F (flat) plates 4a, 4t), 4(j, 4d, upper plates 5&, 5b,
5C and 6d, and a driving force is generated by voice coils 6&, 61), ec, and ad in the magnetic gap. The inside of the box is divided by an Uno frame 7 and an internal edge 8, and is partitioned into a sealed box 9 and a back hole 10. Figure 4 shows speaker 1! It is a block diagram of the driving system. Four driving parts are arranged in parallel. Therefore, 4
The same amount of current flows through the two voice coils, and the imaging plate 2, etc.
It is powered by W and j. FIG. 5 shows a custom-made sound pressure frequency of the speaker with the above configuration. As can be seen from FIG. 5, a dip occurs at the first and second resonance frequencies.

Problems to be Solved by the Invention However, in the above configuration, the position of the node and drive node is determined in a free state where it is not attached to the speaker box 1. Therefore, since the state of the load that is generated on the diaphragm 2 by attaching the diaphragm 2 to the speaker box 1 is not taken into account, the resonance mode on the diaphragm 2 cannot be eliminated, so there is no piston movement, and no sound is generated. There was a problem that peaks and valleys appeared in the pressure frequency characteristics. Further, there is a problem in that it is difficult to measure the position of the nodes of the diaphragm 2 up to high-order vibration modes when it is attached to the speaker box 1.

In view of the above-mentioned problems, the present invention provides a speaker that eliminates the low-order resonance mode 2 on the diaphragm, widens the band in which the piston movement occurs, and has a flat sound pressure frequency characteristic sound.

Means for Solving the Interval Vertex In order to achieve the above objects, the speaker of the present invention provides a plurality of driving points on the diaphragm, and drives the diaphragm by weighting the magnitude of the driving force at each driving point. It is configured to allow

Effect of the present invention With the above-described configuration, one driving position of the diaphragm is arbitrarily determined, and when the diaphragm is driven by a driving force, the current frequency at the trough and driving point determined from the mode measurement results of the driving position on the diaphragm is determined. By inputting the characteristics into a filter, the amount of current to be passed through each voice coil is determined, and the driving force at each position is weighted. Furthermore, the five driving forces can be weighted by changing the length of the voice coil. As a result, it is possible to eliminate the low-order modes on the diaphragm even if the diaphragm is placed anywhere on the diaphragm in a vertical position. As a result, the piston movement takes place over a wide frequency range.

Actual report 11 The present invention will be explained below with reference to Examples.

The speaker has the same configuration as the conventional speaker shown in FIG. A block diagram of the speaker drive system is shown in FIG. 12a to 12d are controlling parts that individually utilize the driving force of each voice coil 6a to 6d; 1.3a to 13;
Jj is a filter in which a custom-made predetermined current frequency i is manually input in order to give an output for weighting the driving force of the diaphragm to each of the control sections 12a to 12d.

The operation of the speaker configured as above will be described below.

In advance, the diaphragm 2 is driven by a driving force, and an acceleration pick is used at the driving position on the imaging plate 2 to perform all mode measurements. The current frequency characteristics 2 at the troughs and driving points are calculated by back calculation from the measurement results, and inputted to the filters 13a to 13 (1).Then, the respective control units 121L to 12d control the weighted currents to the voice coils 6 and 12, respectively.
6d.

As a result, the sound pressure frequency characteristic obtained by this speaker becomes flat as shown in FIG.

In Fig. 2, the horizontal axis represents frequency, and the vertical axis represents sound pressure.

As described above, according to this embodiment, the voice coils 6a to 6
By changing the driving force applied to the diaphragm 2 by d,
Despite the nodal drive in free vibration, the second resonance mode disappears, and a speaker with flat sound pressure frequency characteristics in which the band for pistoning the diaphragm 2 is widened can be obtained. In the example, the diaphragm 2 has a rectangular shape, but the diaphragm may have a circular shape. Also, I drove Furi @ Saka 2, but 1. The driving position may be arbitrary. Furthermore, in this embodiment, the driving force is weighted by changing the amount of current flowing through the voice coils 68 to 6d, but the driving force is weighted by changing the lengths of the voice coils 6a to 6d. You can.

Effects of the Invention The present invention provides a method for controlling the amount of current flowing through each voice coil when a diaphragm is driven by a plurality of voice coils.
By varying this, the diaphragm can be piston-moved over a wide frequency range, resulting in a speaker with a flat sound pressure frequency customization. This can easily achieve the same effect as when a diaphragm is attached to a speaker box and the node is driven at time t, without the difficulty of accurately measuring the position of the node. In addition, by eliminating the low-order modes and widening the frequency band in which the piston can move, the woofer can cover the entire mid-bass band, making it possible to omit the mid-bass, thereby making it possible to obtain an inexpensive speaker. .

[Brief explanation of the drawing]

Fig. 1 is a block diagram of a schematic configuration of a lower drive system of a speaker according to an embodiment of the present invention, Fig. 2 is a sound pressure frequency characteristic diagram of the same speaker, and Fig. 3 is a sectional view of a conventional speaker. Figure 4 is a block diagram of 1 drive system of the same speaker, and Figure 5 (1
It is a custom-made sound pressure frequency diagram of the same speaker. 1...Box, 2...Diaphragm, 3.
...Magnet, 4...Lower plate, 5
...Top plate, 6...Voice coil, Rumored woofer frame, 8...Inner edge, 9...Sealed box, 10・・・・・・
・Back hole, 11...Edge, 12a to 12d・
...Control unit, 13a to 13d...Filter. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 1? . -72d-I'+4□113a
~134-Filter No. 2 Circumferential Recontour (Hzn!-Bonogus

Claims (5)

[Claims] (1) A speaker characterized in that a plurality of driving points are provided on a diaphragm, and the diaphragm is driven by weighting the magnitude of the driving force at each driving point. (2) The speaker according to claim 1, wherein the diaphragm has a substantially rectangular shape or a substantially circular shape. (3) The speaker according to claim 1, wherein a plurality of driving points are provided at nodes of divided resonance of the diaphragm. (4) The speaker according to claim 1, wherein the weighting of the magnitude of the driving force at each driving point is performed by changing the amount of current flowing through the voice coil. (5) The speaker according to claim 1, wherein the magnitude of the driving force at each driving point is weighted by changing the length of the voice coil.