JP2629992B2 - Electronic musical instrument case - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a main body case which also serves as a speaker cabinet of an electronic musical instrument such as a small electronic organ or an electronic piano.

[Summary of the Invention]

The present invention relates to a main body case of an electronic musical instrument configured by combining an upper case and a lower case, wherein a speaker grill is formed in the upper case, and a first rib for partitioning the inside of the upper case and the inside of the lower case, and the upper case And a plate member for acoustically separating the lower case to form a speaker cabinet for accommodating the speaker, and a second rib for enhancing rigidity is provided in a portion of the lower case where the speaker cabinet is formed. By forming an acoustically independent and rigid speaker cabinet inside the main body case to prevent sound leakage and resonance, the bass reproduction range is expanded and the sound pressure in the low range is improved. is there.

[Conventional technology]

The main case of a portable electronic musical instrument consists of an upper case and a lower case.A keyboard and an operation panel are mounted outside, and various electronic circuit boards for forming musical sounds are housed inside. Some are designed to be mounted.

However, in such a conventional speaker mounting structure for an electronic musical instrument, the speaker accommodating portion in the main body case is not particularly partitioned, and there is much sound leakage from the keyboard accommodating portion and the junction between the upper and lower cases. Had been reduced.

Accordingly, the present applicant has formed a speaker grill in an upper case of a main body case of an electronic musical instrument including an upper case and a lower case, and provided a speaker housing ( A proposal has been made to improve the sound quality by minimizing sound leakage and to improve the sound quality by isolating the speaker cabinet (Japanese Patent Application No. 63-312952).

[Problems to be solved by the invention]

However, even in the main body case of the electronic musical instrument proposed earlier, if the operation panel is provided in the upper case itself, there is a problem that sound leaks from the operation panel and the sound quality is deteriorated.

This can be solved by mounting another operation panel on the upper case, but it is disadvantageous in terms of cost and assembly.

Further, since the upper case and the lower case forming the speaker cabinet are generally molded products such as plastic, the thickness cannot be increased so much that the upper case and the lower case vibrate at the sound pressure generated by the speaker, and the sound quality is reduced. Will be reduced.

The present invention has been made in view of these points, so that even if a panel portion is formed in the upper case itself, sound is not leaked from the speaker cabinet, and the thickness of the case does not need to be increased. Sufficient rigidity is obtained, so that it is not vibrated by the sound (especially low sound) generated from the speaker, the low sound reproduction range is expanded to improve the sound quality, and it is easy to assemble and it does not cost much. The purpose is to:

[Means for solving the problem]

In order to achieve the above object, the main case of the electronic musical instrument formed by integrally molding the respective plastics and configured by combining an upper case with an open lower surface and a lower case with an open upper surface is configured as follows. Things.

A speaker grille for attaching a speaker and a sound emitting portion of a bass reflex port are formed near the left and right ends of the upper case.

The left and right speaker cabinets for accommodating the speakers are respectively formed by the first rib for partitioning the inside of the upper case and the inside of the lower case, and the plate member for acoustically separating the upper case and the lower case.

A pair of crank-shaped ribs serving as partition walls of the bass reflex port are formed at the rear of the left and right ends in the upper case so as to be perpendicular to the upper surface and along the rear and side surfaces.

A pair of crank-shaped ribs, which serve as partition walls of the bass reflex port, are formed perpendicularly to the bottom surface and along the back and side surfaces, respectively, at the rear of both left and right ends in the lower case.

A second rib for enhancing rigidity, which is lower in height than the first rib, is provided in a portion of the lower case where the speaker cabinet is formed.

(Operation)

With this configuration, the main body case of the electronic musical instrument has an acoustic structure in the main body case by the first ribs in the upper case and the lower case and a plate member for acoustically separating the upper case and the lower case. The left and right speaker cabinets are formed independently of each other to prevent sound leakage, and the second rib for reinforcing the rigidity provided at the portion of the lower case where the speaker cabinet is formed allows the speaker cabinet portion to be formed. Since the rigidity is increased, resonance due to bass generated from the speaker can be prevented, and the bass reproduction range can be expanded to improve the sound pressure in the bass.

In addition, a relatively long bass reflex port is formed on each speaker cabinet by a pair of crank-shaped ribs provided on the left and right ends of the upper case and the lower case. Is done. As a result, a sound having a frequency lower than the resonance frequency of the bass reflex port emitted from the back side of each speaker is inverted in phase in this port, and is emitted from the sound emitting section in phase with the sound emitted from the front side of the speaker. Therefore, the sense of bass is increased for the listener.

In addition, there is an effect that the strength of the left and right rear corners of the upper case and the lower case can be reinforced by the crank-shaped ribs serving as the partition walls of each bass reflex port.

And even if the operation panel part is formed on the upper case itself,
Since the upper case and the lower case are acoustically separated by the plate member, sound does not leak from the operation panel section.

In addition, the plate member does not require a complicated shape, and the material can be freely selected, so that it can be manufactured at a low cost.

〔Example〕

Hereinafter, embodiments of the present invention will be specifically described with reference to the drawings.

FIG. 1 is an exploded perspective view of a main body case of an electronic musical instrument showing one embodiment of the present invention, and FIG. 2 is a sectional view taken along the line AA of FIG. 1 in an assembled state. Show. FIG. 3 is an exploded perspective view showing the left speaker box portion in FIG. 1 in an enlarged and simplified manner (a second rib and the like are omitted).

As shown best in FIG. 1, the main body case is constituted by an upper case 1, a lower case 2, and a cabinet board 3 as a plate member.

The upper case 1 is formed by integral molding of a plastic. A keyboard mounting portion 10 is provided on the front side of the upper surface over substantially the entire length in the left-right direction, and an operation panel portion 11 is provided on the front surface behind the keyboard mounting portion 10. Near both ends, a pair of speaker grills 12, 12 and a sound emitting portion 13, 13 of a bass reflex port are formed.

The operation panel unit 11 is provided with a large number of switches and indicators, as well as switches for selecting various timbres and effects.

Also, as shown in FIG. 3, inside the upper case 1, first ribs 14, 15 for partitioning the inside to form speaker cabinets, and a partition on the upper case side of the bass reflex port 6 are provided. And a pair of crank-shaped ribs 16 are formed vertically on the upper surface. As shown in FIG. 3, each of the crank-shaped ribs 16, 16 is
Formed along the back and sides.

The lower case 2 is also formed by integral molding of plastic, and a keyboard mounting portion 20 corresponding to the keyboard mounting portion 10 of the upper case 1 is provided on the near side.

Further, first ribs 21 and 22 for partitioning the inside of the lower case 2 to form a speaker cabinet, and a pair of crank-shaped ribs 23 and 23 serving as a partition on the lower case side of the baffle port 6. Each is formed perpendicular to the bottom surface. The crank-shaped ribs 23, 23 are shown in FIGS.
As shown in the figure, the lower case 2 is formed along the back and side surfaces.

24a, 24b, 24c, and 24d are bosses for screwing the upper case 1 after assembly, and 25a, 25b, and 25c are bosses for screwing the capital board 3 together.

Further, a plurality of second ribs 26, 27, and 28 having a lower height than the first ribs 21 and 22 for strengthening rigidity are formed in a portion of the lower case 2 forming the speaker cabinet. The rib 26 is formed in a lattice pattern on the bottom surface 2a, and the rib 27 is formed on the back surface 2b.
The ribs 28 are formed in parallel fin shapes at the portions where the bosses 25a of the first ribs 22 are formed.

The cavity board 3 may be formed of a metal or a wooden plate in addition to plastic, and ribs 30 for reinforcing rigidity are formed in a lattice shape on the left and right sides of the lower surface, and the mounting holes 31a and 31b are formed. ,
31c is provided in plurality.

Next, how to assemble the upper case 1, the lower case 2, and the cavity board 3 will be described.

Inside the speaker grilles 13 of the upper case 1, the speakers 4 are screwed and attached to bosses (not shown) as shown in FIG.

Then, the cavity board 3 is placed on the lower case 2 so as to straddle symmetrically about the first rib 21, and is passed through the mounting holes 31 a, 31, 31 c to each boss 25 a on the lower case 2 side. , 25b, 25c with screws.

The upper case 1 is further placed thereon, and a screw is inserted into a screw hole in each of 24a, 24b, 24c, 24d on the lower case 2 side and screwed to a boss (not shown) on the upper case 1 side. Assemble and integrate.

Incidentally, the joint S ₁ the lower end of the upper portion and the upper case 1 after the surface 17 of the rear surface 29 of the lower case 2 shown in Figure 2, and the first rib 22 of the lower case 2 the upper end and the upper case 1 junction S ₂ between the lower end of the first rib 15 by connexion sealed to each sealing material.

Prior to this assembly, various switches, keys, indicators and the like are attached to the operation panel section 11 of the upper case 1, and an electronic circuit board and a keyboard are also attached. However, they are not directly related to the present invention. Omitted.

As shown in FIG. 2, the first ribs 14 and 15 of the upper case 1, the first ribs 21 and 22 of the lower case 2, and the cavities are provided on the left and right sides of the body case thus assembled. A speaker cabinet 5 sealed by the board 3 and the like is formed, and the speaker 4 is stored therein.

The rigidity of the speaker cabinet 5 is increased by the second ribs 26, 27, 28 of the lower case 2 and the rib 30 of the cabinet board 3.

Therefore, the sound from the speaker 4 does not leak from the inside of the speaker cabinet 5 to the keyboard mounting portions 10 and 20 and the operation panel 11 side of the upper case 1 and resonates at the sound pressure. The sound is not distorted, and the bass reproduction range is extended to improve the sound quality.

In each speaker cabinet 5, a bass reflex port 6 is formed by a crank-shaped rib 16 of the upper case 1 and a crank-shaped rib 23 of the lower case 2, as shown in FIG. Is done.

As a result, the sound having a frequency lower than the resonance frequency ₀ of the bass reflex port 6 emitted from the rear side of the speaker 4 is inverted in phase in this port, and becomes the same phase as the sound emitted from the front side of the speaker 4 from the sound emitting section 13. Since the sound is emitted, the bass feeling is increased for the listener.

The sound having a frequency higher than the resonance frequency ₀ is not inverted in the bass reflex port 6 and is emitted in the opposite phase, and is canceled by the sound emitted from the front side of the speaker 4.

The size and shape of the bass reflex port 6 are calculated together with the vibration frequency ₀ by the Helmholtz equation.

In this embodiment, since the bass reflex port 6 is provided along the left and right rear wall surfaces of the upper case 1 and the lower case 2, the strength of the corners can be reinforced and the device can be downsized.

Note that in this embodiment, 1
Although the speakers are mounted one by one, the number of speakers is not limited to this.

The shapes of the ribs of the upper case 1 and the lower case 2 constituting the bass reflex port (resonance port) and the outlet of the port (sound emitting portion 13) are not limited to the shapes shown in this embodiment, and may have a bass reflex effect. Any shape may be used as long as it has a shape.

The shape of the ribs for increasing the rigidity of the speaker cabinet is not limited to a lattice shape or a parallel fin shape, but may be any shape such as a radial shape, an annular shape, or a corrugated shape.

〔The invention's effect〕

As described above, in the main body case of the electronic musical instrument according to the present invention, even if the operation panel portion is formed directly on the upper case, since the sound does not leak from the speaker cabinet, the operation panel portion is formed as a separate component. You don't have to.

And since only a plate member is attached to the lower case, assembly is easy and cost is advantageous.

Since the reinforcing ribs are formed on the speaker cabinet of the lower case, it is possible to prevent vibration due to bass generated from the speaker without increasing the thickness of the case, thereby improving sound quality. .

The plate member (cavity board) does not require a complicated shape and the material can be freely selected, so that a highly rigid one can be manufactured at low cost.

In addition, each of the left and right speaker cabinets has a relatively long bass reflex port along the back and side surfaces of each case by a pair of crank-shaped ribs provided at the left and right ends of the upper and lower cases. As a result, sound having a frequency lower than the resonance frequency of the bass reflex port emitted from the back side of each speaker is inverted in phase within this port, and is emitted from the sound emitting section in phase with the sound emitted from the front side of the speaker. , Increased bass perception for listeners.

In addition, there is an effect that the strength of the left and right rear corners of the upper case and the lower case can be reinforced by the crank-shaped ribs serving as the partition walls of each bass reflex port.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view of a main body case of an electronic musical instrument showing one embodiment of the present invention, FIG. 2 is a sectional view taken along the line AA of FIG. 1 in an assembled state, and FIG. It is an exploded perspective view which expands and simplifies and shows the left speaker box part in a figure. DESCRIPTION OF SYMBOLS 1 ... Upper case, 2 ... Lower case 3 ... Cabinet board (plate member) 4 ... Speaker 5, Speaker cabinet 6 ... Bass reflex port, 11 ... Operation panel part 12 ... Speaker grill 14,15,21,22 …… First rib 26,27,28 …… Second rib

Claims (1)

(57) [Claims] 1. An electronic musical instrument body case formed by combining an upper case (1) with an open lower surface and a lower case (2) with an open upper surface, each of which is formed by integral molding of plastic. Speaker grilles (12, 12) for mounting speakers (4) near the left and right ends of the upper surface of 1) and sound emitting portions (13, 13) of the bass reflex port (6) are formed, and the upper case (1) is formed. ) And the upper case (1) and the first ribs (14, 15, 21, 22) that partition the inside and the lower case (2), respectively.
A left and right speaker cabinet (5, 5) for accommodating the speaker (4), respectively, by a plate member (3) for acoustically separating the lower case (2) from the lower case (2); A pair of crank-shaped ribs (1) serving as partition walls of the bass reflex port (6) are provided behind the left and right ends of the inside.
6, 16) are formed perpendicularly to the upper surface and along the rear and side surfaces, respectively, and a pair of crank-types which are also provided behind the left and right ends in the lower case (2) and serve as partition walls of the bass reflex port (6). Ribs (23, 23) are formed perpendicularly to the bottom surface and along the rear and side surfaces, respectively, and the first ribs are formed in portions of the lower case (2) where the speaker cabinet (5) is formed. (21,22) A main body case of an electronic musical instrument, wherein second ribs (26,27,28) for heightening rigidity lower than heights are provided.