JPS5845234B2 - coaxial speaker - Google Patents

Description

[Detailed description of the invention] This invention relates to improvements in coaxial speakers.

In general, speaker systems include full-range type systems in which a single speaker unit covers the reproduction band, and multi-way type systems in which the reproduction band is divided into several parts and each uses a dedicated speaker.

The former type has been used for a long time, but it is technically difficult to cover a wide reproduction band with one speaker.

For this reason, the latter type is often used in speaker systems aimed at high-fidelity reproduction.

An example of this is shown in FIG.

FIG. 1 shows a 2-way system, where 1 is a bass speaker, 2 is a treble speaker, and 3 is a cabinet.

In this case, the bass speaker 1 usually has a frequency range of several tens of Hz to 100 Hz.
From 0 to 2000Hz, treble speaker 2 from 1000Hz
The frequency band above 2000Hz will be shared.

In this case, the design of each speaker unit is independent, but since the direction in which the sound comes out differs depending on the frequency band, there is a drawback that the position of the sound image becomes unclear.

In a system with three speakers or more, the number of speakers used increases, so the distribution of sound sources becomes wider.

In order to eliminate this drawback, a coaxial speaker as shown in FIG. 2 is used.

FIG. 2 shows a side sectional view of a device using coaxial speakers, in which a bass speaker 1 and a treble speaker 2 are arranged coaxially.

When viewed from the front of the speaker, the bass speaker 1 and the treble speaker 2 are in the same position, so the localization of the sound image is extremely good.

However, a drawback of this method is that a part of the sound from the high-pitched speaker is reflected by the diaphragm 4 of the low-pitched speaker and undergoes frequency modulation.

In FIG. 2, 11 and 12 are sounds from the high-pitched speakers, 11 is the sound that reaches the listener directly, and 12 is the sound that is reflected by the diaphragm of the low-pitched speaker.

12 is reflected, it is frequency modulated by the vibration frequency of the diaphragm 4 of the bass speaker (denoted as fl), and the sound components (f2± nfl, n is an integer) is generated.

This is called cross-modulation distortion, and it is said to be more audible than harmonic distortion.

This is because the frequency of cross-modulation distortion (f2±nf1) is not an integral multiple of the original frequencies f1', 1i6, and f2.

The occurrence of such cross-modulation distortion is the most serious drawback of coaxial speakers.

The present invention aims to overcome this drawback.

An embodiment of the present invention is shown in FIG.

γ is a diaphragm of the bass speaker 5, which is planar, and
A hole 8 is formed in the center, and a treble speaker 6 is placed in the hole 8 so as to be on the same plane as the diaphragm 1.

Therefore, the sound 12 reflected from the high-pitched speaker 6 toward the diaphragm 7 of the low-pitched speaker 5 is substantially parallel to the vibration plane, and the proportion of the sound 12 subjected to frequency modulation is extremely small.

Furthermore, even if a violation occurs, the amount of cross-modulation distortion that reaches the listener will be even smaller because the direction is away from the front axis of the speaker.

In the embodiment shown in FIG. 3, the diaphragm 7 of the bass speaker 5 and the treble speaker 6 are arranged on the same plane, but this is not an absolutely necessary condition to obtain the effects of the present invention. It is okay if 6 is slightly depressed.

Furthermore, the following are secondary advantages of the present invention.

In the embodiment shown in Fig. 2, the diaphragm 4 of the bass speaker 1 is a baffle surface and is sunk relative to the treble speaker 2, so that transient sounds can be heard from the bass speaker and the treble speaker. There is a difference in the time it takes for the sound to reach the target.

On the other hand, as shown in FIG. 3, the diaphragm 7 of the bass speaker 5
In the case of a flat surface, both bass and treble tones reach the listener with a time delay of approximately 100 Hz, resulting in even more faithful reproduction.

Maf-'! 3 Naturally, since it is symmetrical both horizontally and vertically, it also has the advantage of providing a well-balanced stylistic sound field when performing stereophonic reproduction.

As described above, according to the present invention, a coaxial speaker with excellent characteristics and reduced cross-modulation distortion can be obtained.

In the above embodiment, a two-way system has been described, but it can be easily modified to a three-way or more system with the same configuration.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of a conventionally used two-way speaker device, Fig. 2 is a sectional view of the same coaxial two-way speaker device conventionally used, and Fig. 3 is an embodiment of the present invention. FIG. 2 is a cross-sectional view of an example coaxial speaker. In the figure, 5 is a bass speaker, 6 is a treble speaker, 1 is a diaphragm of the bass speaker, and 8 is a hole provided in the diaphragm of the bass speaker.

Claims (1)

[Claims] 1. In a coaxial speaker in which a plurality of speakers each having a dedicated reproduction frequency band are arranged on the same axis, the shape of the diaphragm of the bass speaker that reproduces the lowest frequency band is made flat, and this diaphragm is A coaxial speaker characterized in that another higher-pitched speaker is disposed in a hole provided in the center of the diaphragm so as to be on the same plane as the diaphragm or slightly lower than the diaphragm.