JPH0733277Y2 - Keyboard type electronic musical instrument - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a keyboard-type electronic musical instrument, and more particularly to improvement of a speaker mounting structure.

"Prior Art" In a keyboard-type electronic musical instrument of this type, generally, a speaker is attached with a structure as shown in FIG. 12 or FIG.

Referring to FIG. 12, the reference numeral 1 is the instrument body,
Reference numeral 2 denotes a shelf board, on which a keyboard 3 and a scale generator (not shown) are installed, and a panel 4 is provided so as to cover substantially the entire surface of the shelf board 2 excluding the operating portion of the keyboard 3. Is attached. A pair of speakers 5 and 5 are attached to the rear surfaces of both sides of the panel 4 so as to face upward, and sound emitting holes 6 are formed at positions facing the speakers 5 and 5, respectively. .

On the other hand, in the case of FIG. 13, the speakers 7, 7 are attached downward on the upper surface of the shelf board 2, and the sound emitting holes 8 are arranged at the positions corresponding to the speakers 7, 7 of the panel 4 and the shelf board 2, respectively. , 9 ... are formed.

"Problems to be solved by the device" However, in the structure in which the speakers 5 and 5 are fixed to the panel 4 as shown in Fig. 12, the characteristics in the high frequency range are relatively good, but the panel 4 is thin. The effect as a so-called baffle plate is small, and the sound waves generated from the rear surface of the diaphragm of the speakers 5 and 5 interfere with the sound waves of the opposite phase generated from the front surface of the diaphragm through the panel 4, which deteriorates the characteristics especially in the low frequency range. there were. This is naturally improved by increasing the thickness of the panel 4, but in that case, the weight of the panel 4 and the molding cost are significantly increased, which is not preferable.

On the other hand, in the structure shown in FIG. 13, since the speakers 7 and 7 are fixed to the thick and strong shelf plate 2, the characteristics in the bass range are relatively good, but the front surface of the diaphragm of the speakers 7 and 7 is relatively good. The sound generated by the speaker is not emitted to the performer and the speaker
Since 7, 7 and the panel 4 are separated from each other, it is difficult for sound waves generated from the rear surface of the diaphragm to pass through the sound output holes 8 of the panel 4, so that sound is muffled inside the panel 4 and the characteristics in the high frequency range are poor. There was a flaw.

"Means for Solving Problems" The present invention has been made to solve the above problems, and includes a shelf board provided on the instrument body and having a keyboard on its upper surface,
A first speaker box portion attached to a portion of the shelf plate other than the keyboard and having the inside communicated with the outside through a communication port formed in the shelf plate, and a wall surface of the first speaker box portion. A speaker fixed to the outside so as to close the formed speaker mounting hole; and a panel mounted on the musical instrument body, wherein the shelf plate is a shelf plate in which the communication port is formed. A main body and a second speaker box which is attached to a lower surface of the shelf main body and which defines a space communicating with the first speaker box portion through the communication port and has a sound emission port formed on its wall surface; It is characterized by consisting of.

[Operation] In the keyboard-type electronic musical instrument shown in the present invention, the sound wave generated from the rear surface of the diaphragm of the speaker is separated from the sound wave generated from the front surface of the diaphragm by the first speaker box portion, and then the communication opening formed on the shelf board is used. By discharging below the shelf,
It is possible to prevent the sound wave from the rear surface of the diaphragm and the sound wave from the front surface of the diaphragm from interfering with each other and prevent the sound pressure from decreasing in the low sound range.

Further, since the second speaker box portion communicating with the first speaker box portion is provided and the sound emission port is formed in this second speaker box portion, the phase of the sound wave from the rear surface of the diaphragm of the speaker is vibrated. The sound pressure in the low-pitched sound range can be increased by causing the sound wave to be emitted from the sound emission port in synchronization with the phase of the sound wave from the front surface of the plate.

Further, since the sound wave from the front surface of the diaphragm of the speaker is emitted upward from the shelf board, the sound wave in the high frequency range with high straightness can easily enter the ears of the performer, and a good high frequency characteristic can be obtained.

[Embodiment] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a sectional view of a keyboard type electronic musical instrument of one embodiment, and FIG. 2 is a plan view.

In the figure, reference numeral 10 is a musical instrument main body, and the musical instrument main body 10 includes a pair of vertical side plates 11 and 11 horizontally attached with a shelf plate 12. As shown in FIG. 4, a keyboard 13, a scale generating device 14, a power supply device 15, and a pair of speaker box parts 16 and 16 spaced from each other are installed on the upper surface of the shelf plate 12.

As shown in FIGS. 5 to 7, these speaker box parts 16 are box-shaped without a bottom, and a speaker 18 is oriented upward in a circular speaker mounting hole 17 formed on the upper surface thereof. It is fitted in without any gap and is screwed to the peripheral portion of the mounting hole 17. A flange portion 19 is formed at the lower end of the speaker box portion 16, and the flange portion 19
Is screwed to the shelf plate 12.

A panel 20 is mounted on the shelf plate 12 to cover the above-mentioned parts of the keyboard 13 except the operation surface, and there is a slight gap between the panel 20 and the speakers 18 and 18. . At the center of the panel 20, there are provided various switch groups 21 and a tiltable scoreboard 22, and the speaker 1
Sound emission holes 23 ... Are formed at both side positions corresponding to 8 and 18, respectively.

The shelf board 12 includes a plate-shaped shelf board body 24 and the shelf board body 24.
2nd speaker box part 25,25 attached to the underside of the
It consists of and.

The shelf main body 24 is provided at a position corresponding to the lower end openings of the speaker box parts 16 and 16 and has a communication port 26 having the same shape as these openings.
Are shaped respectively.

On the other hand, in the second speaker box parts 25, 25, as shown in FIGS. 8 to 10, a partition plate 28 is attached to the center of a rectangular parallelepiped long box 27 having a length substantially equal to that of the shelf main body 24. It has an integral structure in which it is divided into two air chambers in the longitudinal direction, and the top of the long box 27 is closed by a top plate 29. The top plate 29 has a communication port 26 at a position corresponding to the communication port 26 of the shelf body 24.
The openings 30 of the same shape as the above are formed.
A flexible packing 31 for airtightly closing a gap between the shelf body 24 and the top plate 29 is attached to the peripheral edge of the. In addition, a circular sound emission port 32 is formed at a predetermined position on the bottom surface of the second speaker box section 25, and a metal net 33 that closes the sound emission port 32.
Is attached, and a felt 34 is attached to the entire inner surface thereof except the opening 30 and the sound output port 32. The second speaker box parts 25, 25 are provided with a clasp 35 with the lower surface of the top plate 29 and the upper surface of the shelf main body 24 slightly separated.
It is fixed to the shelf body 24 by. When the speakers 18, 18 are sounded in this state, the sound wave generated from the rear surface of the diaphragm of the speaker 18 is emitted from the sound emission port 32 through the speaker box section 16 and the second speaker box section 25, and the diaphragm of the speaker 18 is emitted. It is configured to have the same phase as the sound wave generated from the front surface.

According to such a keyboard type electronic musical instrument, the sound wave generated from the front surface of the diaphragm of the speaker 18 and the sound wave generated from the rear surface of the diaphragm are separated by the speaker box section 16, and the sound pressure in the low range due to these interferences is generated. You can prevent the decline. Further, in this embodiment, the sound wave from the rear surface of the diaphragm of the speaker 18 is transmitted to the second speaker box portion 25, and is emitted from the sound output port 32 in the same phase as the sound wave from the front surface of the diaphragm. Therefore, the action of amplifying the sound pressure can be obtained especially in the low tone range. Therefore, due to these effects, it is possible to remarkably improve the characteristics in the bass range as compared with the conventional electronic musical instrument of the same kind.

Further, the speakers 18, 18 are installed in the vicinity of the sound output holes 23 ...
Sound waves from the front surface of the diaphragm 8 are emitted in a direction in which the player can easily hear the sound without being confined in the panel 20, so in a high-frequency range with high straightness compared to an electronic musical instrument having a speaker mounted on a shelf board. The characteristics can also be improved.

Note that FIG. 11 is a graph of frequency characteristics showing the effect of the above-mentioned embodiment, and “Experimental Example 1” is a result of actually manufacturing and measuring a keyboard type electronic musical instrument having the configuration of the above-mentioned embodiment, “Experimental example 2” is a result of the keyboard type electronic musical instrument having the configuration in which the second speaker box part is omitted from “Experimental example 1”, and “Comparative example” is that the speaker is directly attached to the panel. The results of an example of a keyboard-type electronic musical instrument commercially available in the past are shown. From this graph, it has been clarified that the frequency characteristics are remarkably improved in the example.

It should be noted that in the above embodiment, the second speaker box unit 25, 25
However, it is also possible to omit these.

Further, in the above embodiment, the instrument body 10 is a side plate as a leg.
Although the shape has 11 and 11, the present invention can also be applied to a desk-top type electronic musical instrument having no such legs.

"Effect of Device" As described in detail above, in the keyboard electronic musical instrument shown in the present invention, the sound wave generated from the rear surface of the diaphragm of the speaker is
The speaker box separates the sound waves generated from the front surface of the diaphragm, and emits the sound waves from the rear surface of the diaphragm and the sound waves from the front surface of the diaphragm by discharging the sound waves below the shelf plate from the communication opening formed on the shelf board. It is possible to prevent interference and prevent a decrease in sound pressure in the low frequency range.

Further, since the second speaker box portion communicating with the first speaker box portion is provided and the sound emission port is formed in this second speaker box portion, the phase of the sound wave from the rear surface of the diaphragm of the speaker is vibrated. The sound pressure in the low-pitched sound range can be increased by causing the sound wave to be emitted from the sound emission port in synchronization with the phase of the sound wave from the front surface of the plate.

Further, since the sound wave from the front surface of the diaphragm of the speaker is emitted upward from the shelf board, the sound wave in the high frequency range with high straightness can easily enter the ears of the performer, and a good high frequency characteristic can be obtained.

That is, in the keyboard type electronic musical instrument shown in the present invention,
It is possible to obtain excellent characteristics in any of the high range and to improve musical instrument performance.

[Brief description of drawings]

1 to 10 show a keyboard type electronic musical instrument of an embodiment of the present invention. FIG. 1 is a sectional view, FIG. 2 is a plan view, and FIG. 3 is a III-III line in FIG. Sectional view, FIG. 4 is a plan view taken along line IV-IV in FIG. 1, FIG. 5 is a plan view showing a speaker box portion, FIG. 6 is a bottom view of the same portion, and FIG. 7 is a side surface of the same portion. FIG. 8 is a plan view showing the second speaker box portion, FIG. 9 is a sectional view taken along the line IX-IX in FIG. 8, and FIG. 10 is a plan view of the same portion. FIG. 11 is a graph of frequency characteristics showing the effect of the embodiment. On the other hand, FIG. 12 and FIG. 13 are sectional views of different conventional keyboard type electronic musical instruments. 10 ... Instrument body, 12 ... Shelf board, 13 ... Keyboard, 16 ... Speaker box section (first speaker box section), 18 ... Speaker, 17
… Speaker mounting hole, 20… Panel, 24… Shelf main body, 25… Second speaker box section, 26… Shelf communication port, 32… Sound emission port.

Claims (2)

[Scope of utility model registration request] 1. A shelf board provided on a main body of a musical instrument and having a keyboard installed on its upper surface, and a shelf plate mounted on a part of the shelf board excluding the keyboard and having its inside formed through a communication port formed on the shelf board to the outside. A first speaker box portion communicating with the speaker; a speaker fixed outward so as to close a speaker mounting hole formed in a wall surface of the first speaker box portion; The shelf plate is attached to a lower surface of the shelf plate body and communicates with the first speaker box section through the communication port. A keyboard-type electronic musical instrument characterized by comprising a second speaker box which defines a space and has a sound emission opening formed on its wall surface. 2. The keyboard-type electronic musical instrument according to claim 1, wherein a sound absorbing material is attached to an inner surface of the second speaker box portion.