JPH04318799A - Speaker equipment - Google Patents

Abstract

PURPOSE:To prevent the reduction in a sudden sound pressure level at a low frequency by driving 1st and 2nd speaker units in phase at a frequency below a phase inversion frequency of an all path circuit so as to prevent cancellation due to an inverted phase. CONSTITUTION:A 1st speaker unit 1 is fitted to one buffle face of a cabinet 3 and a 2nd speaker unit having the same characteristic as that of the speaker 1 is fitted to a buffle face opposite to the buffle face on which the speaker 1 is mounted. An all pass circuit 4 is connected to the speaker 1 and the phase is inverted around the frequency f1 as a border. Then both the speakers 1, 2 are driven in opposite phase at a frequency band more than the frequency f1 and driven in in-phase for a frequency band below the frequency f1. Since the speakers having dual directivities are provided, a decrease in a rapid sound pressure level at a low frequency is avoided and an excellent surround effect is obtained.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bidirectional speaker device suitable for a surround sound field reproduction device.

0002

2. Description of the Related Art In recent years, improvements in video technology have made it possible to show movies on a large screen even at home. Along with this, sound equipment has also come to be required to have the power and sound quality suitable for large screens. Against this background, as shown in FIG.
It is often a so-called surround sound field reproducing device that uses two or more speaker devices 9 on the side or rear of a book speaker device 8.

[0003] The front channel of this surround sound field reproduction device is an indirect signal that is synthesized by using a special processing device to synthesize the signals of the audio of the software being played, background music, etc., and the rear channel is the signal of the front channel. It handles signals related to sound and resonance. Speaker devices for each channel are basically required to have performance that corresponds to the signals they handle, and front speaker devices are required to have good clarity and sound image localization.

[0004] Furthermore, since indirect sound is handled in the rear channel, it is desirable to install the speaker device so that the sound from the speaker device reaches the viewer directly and does not localize the sound image, in order to obtain a good surround effect. In rare cases, there is a method of increasing the above-mentioned effect by using a large number of rear speaker devices 9 to surround the viewer as shown in FIG. 4, for example, to disperse the sound sources. However, on the other hand, it is required to obtain the maximum effect with as few devices as possible due to the problem of installation location and costs.

[0005] Furthermore, if the timbre of the direct sound from the front speaker device and the indirect sound from the rear speaker device are different, it gives a sense of discomfort to the viewer, so the timbre of the front speaker device and the rear speaker device are the same. It is desirable to be present.

In view of the above points, a speaker device as shown in FIG. 5 has been proposed as a rear speaker device. In FIG. 5, 1 and 2 are speaker units having the same performance, 3 is a cabinet, and speaker unit 1
, 2 are electrically connected to operate in opposite phases. FIG. 6 shows the speaker device shown in FIG.
This is an example of polar coordinate directivity characteristics when the front side of speaker unit 1 is set at 0° and the front side of speaker unit 2 is set at 180°.
It exhibits bidirectionality with the minimum sound pressure at positions equidistant from the speaker units 1 and 2, that is, on the sides of the cabinet.

FIG. 7 is an example of an audio device that is combined with a home video playback device 7 that uses the speaker device shown in FIG. 5 as a rear speaker device. Since the directional characteristics of the rear speaker device 9 are bidirectional as shown in FIG. Viewer 1 while using
0 can be given a good surround effect.

[0008]

[Problems to be Solved by the Invention] However, when observing the speaker device shown in FIG. Distance L at which sound emitted from a speaker unit far from a point reaches the observation point
At frequencies below fc, where the distance difference L2-L1 (hereinafter referred to as the effective distance between both speaker units) from the two speaker units is half a wavelength, the sound pressures of both speaker units cancel each other out, causing a sudden increase in the sound pressure. (Figure 8). Therefore, if you want to reproduce low frequencies, you must either make the cabinet larger and increase the effective distance between both speaker units to lower the frequency fc at which cancellation begins, or use the amplifier that drives the speaker system to significantly reproduce low frequencies. This poses a major practical problem since it requires level enhancement correction.

[0009] The present invention solves the above-mentioned conventional problems, and provides a speaker device that can provide a good surround effect to the viewer even though a small number of speakers are used, and that does not cause a sudden level drop in the low frequency range. With the goal.

0010

[Means for Solving the Problems] In order to solve this object, the speaker device of the present invention includes a first speaker unit attached to one baffle surface of a cabinet, and a first speaker unit attached to one baffle surface of a cabinet.
A second speaker unit, which has the same characteristics as the speaker unit and is attached to a baffle surface facing the baffle surface on which the first speaker unit is attached, is connected to the first speaker unit and has a frequency fl. The first and second speaker units are electrically connected so that they are driven in opposite phases to each other in a frequency band above the frequency fl, and in the same phase in a frequency band below the frequency fl. It has the following configuration.

[0011] Also, at an observation point on the front axis of the first speaker unit, the distance from which the sound emitted from the first speaker unit reaches the observation point and the sound emitted from the second speaker unit are observed. It has a configuration in which the fl is set near the frequency fc where the difference in distance up to the point is half a wavelength.

0012

[Operation] With the above-described configuration, the first and second speaker units are driven in the same phase at frequencies below the phase inversion frequency fl of the all-pass circuit, and cancellation due to opposite phases does not occur. A decrease in sound pressure level can be prevented.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows a sectional view of a speaker device according to an embodiment of the present invention, showing a speaker unit 1 attached to one baffle surface of a cabinet, and a speaker unit 1 having the same characteristics as the speaker unit 1. A speaker unit 2 attached to a baffle surface facing the baffle surface on which the unit 1 is attached, and an all-pass circuit 4 connected to the speaker unit 1 and whose phase is inverted at the frequency fl.
It is composed of. Then, in the frequency band above the frequency fl, the speaker units 1 and 2 are in opposite phase to each other, and in the frequency band below the frequency fl, the speaker units 1 and 2
are electrically connected so that they are driven in the same phase.

Frequency f at which the phase of the all-pass circuit is inverted
When observing in front of speaker unit 1 or 2, l is the distance L1 at which the sound emitted from the speaker unit near the observation point reaches the observation point, and the distance L1 at which the sound emitted from the speaker unit far from the observation point reaches the observation point. If the distance difference L2-L1 (effective distance between both speaker units) is set to a frequency fc that corresponds to a half wavelength, the two speaker units will be driven in the same phase in the frequency band below fc, so the two speaker units will be driven in both directions. As shown in FIG. 2, the reproduction band can be extended to a frequency band lower than fc, as shown in FIG. 2. Note that depending on the low-frequency characteristics of the speaker unit and the capacity of the cabinet, the connection between the band and the high-frequency range may be better if the frequency fl is higher or lower than fc. It is sufficient to set the frequency near fc.

FIG. 3 is a layout diagram showing an example of a sound reproducing device in which the speaker device according to the present invention shown in FIG. 1 is used as a rear speaker device and is combined with the home video reproducing device 7. This is an example in which they are placed on both sides of the viewer 10. The directional characteristics of the rear speaker device 9 are bidirectional at frequencies above the frequency fl at which the phase of the all-pass circuit is reversed, so the sound pressure of the direct sound from the rear speaker device is minimized near the listening position, and the sound pressure of the direct sound is higher than the direct sound. Also, the indirect sound becomes dominant, and a good surround effect can be provided to the viewer 10.

As described above, with the configuration of this embodiment, it is possible to realize a speaker device that does not cause a sudden drop in sound pressure level in the low range and can obtain a good surround effect.

[0018] Although bidirectionality is lost at frequencies below fc, the surround effect is not impaired due to the nature of human hearing, which makes the sense of localization ambiguous for low-frequency sounds. Since there is no sudden drop in sound pressure level in the low range, it is easy to match the sound quality of the front and rear speaker devices.

In addition, although speaker units 1 and 2 having the same characteristics are used in this embodiment, a plurality of multi-way speaker devices constituted by a plurality of speaker units each having the same characteristics and a dividing network are used. Needless to say, it is also effective to use a multiway speaker device and connect the above-mentioned all-pass circuit to one side of the multiway speaker device.

[0020]

As is clear from the above embodiments, according to the present invention, the first speaker unit attached to one baffle surface of the cabinet has the same characteristics as the first speaker unit, and the first speaker unit has the same characteristics as the first speaker unit. a second speaker unit attached to a baffle surface facing the baffle surface to which the first speaker unit is attached, and the first speaker unit 1.
is connected to an
and the second speaker unit are in opposite phase to each other, and the frequency f
In the frequency band below l, they are electrically connected so that they are driven in the same phase, and the frequency fl is set near the frequency fc, so a good sound pressure drop does not occur at frequencies below fc, and a good result is achieved. It is possible to provide a speaker device that can obtain a surround effect.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a speaker device according to an embodiment of the present invention.

[Figure 2] Characteristic diagram showing an example of sound pressure frequency characteristics of the same speaker device

[Fig. 3] Layout diagram showing an example of a sound reproduction device used as a rear speaker device of the same speaker device.

[Fig. 4] Layout diagram showing an example of a sound reproduction device using a conventional speaker device as a rear speaker device.

[Figure 5] Cross-sectional view of a conventional bidirectional speaker device

[Figure 6] Directional characteristic diagram showing an example of polar directivity of a bidirectional speaker device

[Fig. 7] Layout diagram showing an example of a sound reproduction device using a conventional bidirectional speaker device as a rear speaker device.

[Fig. 8] Characteristic diagram showing an example of sound pressure frequency characteristics of a conventional bidirectional speaker device

[Explanation of symbols]

1 Speaker unit 2 Speaker unit 3 Cabinet 4 All-pass circuit

Claims (2)

[Claims] 1. A first speaker unit attached to one baffle surface of a cabinet, having the same characteristics as the first speaker unit, and facing the baffle surface to which the first speaker unit is attached. A second speaker unit attached to the baffle surface, and an all-pass circuit connected to the first speaker unit and whose phase is inverted with a frequency fl as a boundary, and in a frequency band equal to or higher than the frequency fl, the first speaker unit and the first speaker unit are connected to the first speaker unit. A speaker device in which two speaker units are electrically connected so that they are driven in opposite phases to each other, and the first and second speaker units are driven in the same phase in a frequency band below the frequency fl. 2. The frequency fl of the all-pass circuit is set at an observation point on the front axis of the first speaker unit,
A frequency fc whose half wavelength is the difference between the distance from which the sound emitted from the first speaker unit reaches the observation point and the distance from which the sound emitted from the second speaker unit reaches the observation point. The speaker device according to claim 1, wherein the speaker device is set to.