JPH07284184A - Loudspeaker device - Google Patents

Abstract

PURPOSE:To obtain a flat sound pressure frequency characteristic and to obtain a loudspeaker device performing an excellent low level sound reproduction by arranging a specified partition plate on the way of the route of a sounding tube for guiding the sound waves coupled with the back face of a loudspeaker. CONSTITUTION:This device is provided with a sounding tube 5 continuously extended to the side of the back face of a loudspeaker 6, a partition plate 7 arranged slantly to the side wall of this sounding tube 5 and an opening part 8 directed to the side of the front surface at the end part of the sounding tube 5. The sound waves radiated from the back face of the loudspeaker 6 is radiated in the air from the opening part 8 through the sounding tube 5. At this time, because the plate 7 does not have a surface parallel to the side wall of the sounding tube 5, standing waves do not generate on this surface. Because space where air is capable of freely passing is secured around the plate 7, the plate 7 hardly resists the pass of sound waves, and the same sound pressure as that generated when the plate 7 does not exist can be obtained. As a result, a smooth and excellent acoustic characteristic free from a sharp peak can be obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a speaker device having an acoustic tube provided on the back surface of a speaker used in various audio equipment.

[0002]

2. Description of the Related Art Conventionally, a speaker device having an acoustic tube coupled to the back surface of the speaker has been used as one of the techniques for expanding the low-frequency reproduction of the speaker device.

Hereinafter, such a conventional speaker device will be described with reference to the drawings.

FIG. 3 is a structural cross-sectional view of the conventional speaker device described above. In FIG. 3, 1 is a cabinet,
2a, 2b, 2c, 2d and 2e are partition plates provided on the front and rear plates of the cabinet 1, 3 is an opening provided in the lower part of the front plate of the cabinet 1, and 4 is attached to the upper part of the front plate. It is a speaker.

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

A partition plate 2 provided in the cabinet 1
Reference numerals a, 2b, 2c, 2d, and 2e constitute an acoustic tube, and sound waves emitted from the back surface of the speaker 4 pass through the acoustic tube and are radiated from the opening 3 thereof.

The acoustic tube resonates at a specific frequency determined by its total length, the total length of the acoustic tube is L, and the speed of sound in air is C.
Then, the resonance frequency (f _h ) is f _h = C / 4L × (2
n + 1), where n = 0, 1, 2, ...
At = 0, a quarter wavelength is loaded in the acoustic tube to cause resonance, and acoustically increased sound is radiated from the opening 3 of the acoustic tube.
The efficiency is greatly improved near the bass reproduction limit.

At a frequency of 1/2 wavelength in the acoustic tube, the sound emitted from the front surface of the speaker 4 and the sound emitted from the opening section 3 of the acoustic tube that is originally in opposite phase to the sound from the front surface. The sound from the back surface of the speaker 4 has the same phase and is added due to the phase delay of a half wavelength, and the sound pressure level increases.

Further, when n = 2, a 3/4 wavelength is placed in the acoustic tube, and acoustically increased sound is radiated from the opening 3 of the acoustic tube as in the case of n = 0, and high efficiency is achieved in the low tone range. It was possible to realize various speaker devices.

[0010]

However, in the conventional structure having the straight horn as described above, a part where the outer wall of the cabinet 1 of the acoustic tube and the partition plates 2a, 2b, 2c form a parallel surface is generated. A standing wave is generated between the parallel planes, and a sharp peak occurs at a specific frequency as shown by the reproduced sound pressure frequency characteristic (dotted line in FIG. 2). For this reason, there is a drawback that high-fidelity reproduction with flat sound pressure frequency characteristics cannot be performed.

There is also a method of absorbing a sound pressure peak by inserting a sound absorbing material or the like into a part of the acoustic tube, but this type of speaker device effectively utilizes the resonance phenomenon of the acoustic tube to reproduce the low tone. Therefore, there is a problem that it is not preferable to use the sound absorbing material because it is carried out.

An object of the present invention is to solve the above problems and to provide a high performance speaker device having a smooth sound pressure frequency characteristic and excellent low tone reproduction.

[0013]

In order to solve this problem, the speaker device of the present invention has an acoustic pipe for guiding a continuously extended sound wave having a polygonal cross section, which is coupled to the back surface of the speaker.
A partition plate is provided in the middle of the path of the acoustic tube so as to ensure a space through which the sound waves can pass and is arranged non-parallel to the side wall of the acoustic tube.

[0014]

With this structure, the sound wave from the back surface radiated from the speaker does not generate a standing wave at the position where the partition plate is provided because there is no parallel surface between the partition plate and the wall surface of the acoustic tube, and therefore the sound is generated. Smooth because no pressure peaks occur,
A speaker device having excellent characteristics can be obtained.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A speaker device according to an embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a structural cross-sectional view of the speaker device in the same embodiment. In FIG. 1, 5 is an acoustic tube continuously extended to the back side of the speaker 6, and 7 is this acoustic tube 5.
The partition plate 8 is arranged non-parallel to the side wall of the acoustic tube 5, and the opening 8 is directed toward the front surface at the terminal end of the acoustic tube 5.

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

First, the sound wave radiated from the back surface of the speaker 6 passes through the acoustic tube 5 and is radiated from the opening 8 into the air. At this time, since the partition plate 7 does not have a parallel surface with the side wall of the acoustic tube 5, no standing wave is generated on this surface. Further, since a space through which air can freely pass is secured around the partition plate 7, it is unlikely that it will be a resistance when a sound wave passes, and a sound pressure similar to that when the partition plate 7 is not provided can be obtained. It is a thing.

As a result, as shown by the solid line in FIG. 2, as compared with the conventional speaker device in which the acoustic tube 1 is coupled, sharp and smooth peaks are removed and excellent acoustic characteristics are obtained.

Although only one partition plate 7 is arranged in the present embodiment, the present invention is not limited to this, and the same effect can be obtained even if a plurality of partition plates are arranged. However, the shape thereof is not limited to a linear plate, and may be a plate constituted by a curved line.

[0021]

As described above, the speaker device according to the present invention does not obstruct the passage of the sound wave in the middle of the path of the sound tube that couples the sound wave coupled to the back surface of the speaker, and is parallel to the side wall of the sound tube. It is possible to remove the peak of the sound pressure due to the standing wave by the parallel facing surfaces of the side wall by maintaining the reproduction effect of the bass range enhancement of the acoustic tube as it is by arranging the partition plates non-parallel so as not to have As a result, a flat sound pressure frequency characteristic can be obtained, and a speaker device capable of excellent bass reproduction can be realized.

[Brief description of drawings]

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

FIG. 2 is a reproduction sound pressure frequency characteristic diagram comparing characteristics of the speaker device and a conventional speaker device.

FIG. 3 is a structural cross-sectional view of a conventional speaker device.

[Explanation of symbols]

 5 Acoustic tube 6 Speaker 7 Partition plate 8 Opening

Claims (1)

[Claims] 1. A sound tube for guiding a continuously extended sound wave having a polygonal cross section is coupled to the back surface of a speaker, a space through which the sound wave can pass is secured in the middle of the path of the sound tube, and the sound tube is provided. Device provided with a partition plate arranged non-parallel to the side wall of the speaker.