JP2580213B2 - Speaker system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention attaches a plurality of speaker units to one cabinet, and a non-vibration system such as a magnetic circuit vibrates due to a reaction of vibration of a speaker diaphragm. The present invention relates to an improvement of a speaker system for preventing deterioration of sound quality due to vibration transmitted to a cabinet and vibration of the cabinet.

[Conventional technology]

FIG. 4 shows an example of this type of conventional speaker system, which will be described below.

Reference numeral 1 denotes a cabinet having openings 2a and 3a formed at the same positions of baffle boards 2 and 3 provided on the front and rear surfaces thereof, and speaker units 4 and 5 attached to the cabinets facing the front and rear surfaces, respectively.

Then, the magnetic circuits 4a, 5a of the speaker units 4, 5 are connected by a connection rod 6 having high rigidity, and the two magnetic circuits 4a, 5a are integrated.

Signal currents are applied to the speaker units 4 and 5 in the same phase. Therefore, when the diaphragm of the speaker unit 4 moves forward, the diaphragm of the speaker unit 5 moves rearward.

Therefore, the directions of the reactions occurring in the non-vibrating systems such as the magnetic circuits 4a and 5a of the speaker units 4 and 5 are opposite to each other, and the non-vibrating systems act to cancel the vibrations,
This is to prevent vibration of the cabinet 1.

[Problems to be solved by the invention]

However, generally, the cabinet 1 used in such a speaker system is a rectangular parallelepiped.

In the case of the rectangular parallelepiped cabinet 1, sound waves generated from the speaker unit 7 are reflected and diffracted at the corners of the cabinet 1 as shown in FIG. Interference with the reflected waves causes disturbance in sound pressure frequency characteristics.

In order to prevent this interference, there is a speaker system in which the corner 1a of the cabinet 1 is not formed at an acute angle as shown in FIG. 6 but is rounded to reduce the reflection and diffraction of sound waves from the speaker unit 7.

However, even in this speaker system,
If R in 1a is smaller than the wavelength of the sound wave in question, the effect cannot be obtained, and this R needs to be at least about 1/4 wavelength.

Therefore, if it is attempted to prevent interference at frequencies below the midrange, the radius of the corner 1a becomes large, and the cabinet 1 becomes enormous.

The ideal way to avoid such diffraction effects is to use a speaker embedded in an infinite baffle.
This is not possible in practice.

[Object of the invention]

The present invention solves the above-mentioned problems in the conventional speaker system, prevents vibration of a non-vibration system such as a magnetic circuit of a speaker unit, prevents vibration of a cabinet, and prevents disturbance of sound pressure due to diffraction. Another object of the present invention is to improve the sound quality of a speaker system.

[Summary of the Invention]

According to the present invention, in order to achieve the above object, a first speaker unit is accommodated in a front surface of a cabinet and mounted in the cabinet, and a second speaker unit is mounted on a rear surface of the cabinet so as to protrude rearward of the cabinet. The gist is that a non-vibration system such as a magnetic circuit of a speaker unit is connected and integrated by a connecting means.

(Example of the invention)

Next, an embodiment of the present invention will be described below with reference to FIGS.

In FIG. 1, reference numeral 11 denotes a cabinet, and openings 11a and 11b for mounting speaker units 12 and 13 are provided on the same line on the front and rear surfaces thereof.

A speaker unit 12 is mounted on the front opening 11a such that the magnetic circuit 12a is housed in the cabinet 11, and the speaker unit 1 is also mounted on the rear opening 11b.
3 is mounted with the magnetic circuit 13a protruding rearward of the cabinet 11.

Therefore, the diaphragms 12b and 13b of the speaker units 12 and 13 are attached toward the front.

Then, the magnetic circuits 12a and 13a of the speaker units 12 and 13 are connected by a non-magnetic rigid connection rod 14 such as aluminum or brass, and the non-vibration systems of the speaker units 12 and 13 are integrated to form the same vibration system. And

Further, it is desirable that the same output is obtained with the same driving force, that is, the same speaker unit is used for the speaker units 12 and 13.
Are applied with signal currents in opposite phases.

That is, to make the currents applied to the speaker units 12 and 13 have opposite phases, the connection terminals of the speaker units 12 and 13 may be inverted.

Then, diaphragms 12b and 13b of speaker units 12 and 13 vibrate in opposite phases.

For this reason, the sound waves radiated to the front and rear surfaces of the cabinet 11 become wavefronts as shown in FIG. 2 and propagate to the space, and the sound waves emitted from the two diaphragms 12b and 13b collide with each other.
That is, the center line A between the two speaker units 12 and 13 has the same effect as the infinite baffle surface shown in FIG. 3, and the wavefronts of both have almost the same effect.

Further, the reaction of the driving force generated in the voice coils of the speaker units 12 and 13 generates a force for moving the non-vibration system such as the magnetic circuits 12a and 13a, but the directions of the forces generated in the two speaker units 12 and 13 are opposite to each other. As a result, the forces cancel each other out, and the vibration of the non-vibrating system is prevented.

As described above, in order to integrate the non-vibration system of both speaker units 12 and 13 as the same vibration system, it is desirable that the length of the connecting rod 14 is short, and the length of the connecting rod 14 from the center line A to the diaphragms 12b and 13b is also good. It is desirable that the depth of the cabinet 11 be equal to or less than the depth of the speaker unit 12 because the effect of the baffle is closer to the infinity when the distance is shorter.

Further, the cancellation operation is performed for even harmonic distortion caused by amplitude non-linearity of the edges 12c and 13c supporting the diaphragms 12b and 13b.

In the embodiment of FIG. 1, the magnetic circuits 12a and 13a are connected by the connecting rod 14, but the frames 12c and 13
Although c may be connected, the vibration canceling effect is lost above the resonance frequency of the frames 12c and 13c.

Normally, this frequency has a disadvantage that it is lower than that obtained by connecting the magnetic circuits 12a and 13a of FIG. 1 with the connecting rod 14. However, it is also possible to design such that the effect is sufficiently obtained up to the middle range. It is possible.

〔The invention's effect〕

As described above, since the present invention produces the same effect as installing an infinite baffle on the center line between the diaphragms of the front and rear speaker units, the diffraction effect generated at the corner of a general rectangular parallelepiped cabinet is obtained. Disturbance in sound pressure frequency characteristics can be prevented.

Also, by driving the two speaker units with the same driving force and opposite phases, the reaction forces of the diaphragm driving cancel each other, and the vibration of the non-vibrating system such as the magnetic circuit and the frame of the two speaker units is prevented. Since vibration of the cabinet is prevented, the rigidity of the cabinet can be reduced, and the weight of the speaker system can be reduced.

Further, for the above-mentioned reason, even-order distortion of non-linear distortion of an electric system and a mechanical system is canceled, and a low distortion speaker system can be obtained.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of one embodiment of the present invention, FIG. 2 is an explanatory diagram showing the state of the wavefront of the sound wave, FIG. 3 is an explanatory diagram showing the state of the wavefront of the sound wave of the infinite baffle, 4 is a longitudinal sectional view of a conventional vibration canceling type speaker system, FIG. 5 is a transverse sectional view showing a sound wave diffraction state of a rectangular parallelepiped cabinet, and FIG. FIG. 11… Cabinet, 12,13 …… Speaker unit, 12
a, 13a: magnetic circuit, 12b, 13b: diaphragm, 14: connecting rod.

Claims (1)

(57) [Claims] A cabinet having openings on the front and rear sides for mounting speakers, a first speaker unit housed in the cabinet and mounted on the opening on the front side, and a cabinet protruding out of the cabinet and having an opening on the rear side. A second speaker unit mounted in the same direction as the first speaker unit; a driving unit for driving signals for driving the first speaker unit and the second speaker unit in opposite phases; A speaker system comprising: connecting means for connecting a non-vibration system such as a magnetic circuit with a rigid non-magnetic material.