JP3918825B2 - Electronic keyboard instrument - Google Patents

Description

  The present invention relates to an electronic keyboard instrument, and more particularly to an improvement in a sound emission structure from a speaker.

  In an electronic keyboard instrument having a flat board-like casing as a whole, the conventional speaker arrangement structure is a type in which a sound emitting opening is provided on the top of the casing and the speaker is arranged with the front facing this opening. And a type in which a sound emitting opening is provided on the rear surface of the housing, and a speaker is disposed with the front facing the opening. In the former case, since the sound is emitted above the musical instrument, for example, when the audience is assumed to be located some distance behind the musical instrument, the passage of the sound to the audience is not sufficient. On the other hand, when the speaker is arranged facing the rear of the instrument as in the latter case, the sound passing to the audience is improved, but the sound passing by the performer facing the keyboard on the front of the instrument is improved. not enough. For this reason, a mistouch due to a sense of incongruity of the key touch response due to poor feedback of sound to the performer results in a decrease in performance expressiveness.

On the other hand, in the following Patent Document 1, the speaker is disposed obliquely upward at a predetermined position near the back of the musical instrument casing, thereby improving the acoustic characteristics on both the audience side and the performer side. Things are shown. However, in the case where the speaker is directed obliquely upward as described above, there is a limit to the acoustic characteristics of the front (near the player) and the rear (near the audience), which is insufficient. In addition, it is not easy to manufacture and assemble, and the cost is increased.
In general, since sound propagation is easily diffracted in the low sound range, it is relatively easy to hear regardless of the position of the speaker (directivity direction of the front surface of the speaker). On the other hand, the high sound range is affected by the arrangement of the speakers, and is difficult to hear at a position where the passage of sound is not sufficient. Therefore, in the above-described prior art, the acoustic characteristic particularly in the high sound range becomes a problem.

For example, it is possible to improve the sound characteristics regardless of the position of the listener by adding speakers for the high sound range to compensate for the sound characteristics in the high sound range, or providing multiple speakers in different sound emission directivity directions. It is. However, if it does so, the manufacturing cost will become high and the problem that a musical instrument housing will necessarily enlarge will arise.
The present invention has been made in view of the above points, and it is an object of the present invention to provide an electronic keyboard instrument that can improve acoustic characteristics at any position on the audience side and the performer side with a simple configuration. is there.

The present invention includes a keyboard provided near the front surface of the housing, a main tone hole provided on the back surface of the housing, and a speaker provided in the housing with the front surface facing the main tone hole. In the electronic keyboard instrument provided, in the roof plate portion constituting the upper surface of the housing, a subtone hole made of a horizontally long hole is formed at a predetermined position within the depth length of the speaker, and the short side of the subtone hole is the short side of the subtone hole. And the long side of the subtone hole is perpendicular to the sound output axis of the speaker, and the center of the subtone hole is closer to the side of the instrument from the center of the sound output axis of the speaker. The sub-tone hole is partly located above the side surface of the speaker and is displaced by a predetermined distance. It characterized thereby sounding the sound vibrations efficiently upward.

The front surface of the speaker provided in the housing is directed to the main tone hole provided on the back surface of the housing, and the sound output from the front surface of the speaker is directed toward the back of the instrument (for example, directed to the audience). Sounded. The sound from the front of the speaker is emitted toward the back of the instrument, but the low frequency range is easily diffracted, so it resonates well even on the player's side facing the keyboard on the front of the instrument. On the other hand, since the subtone hole is formed in the roof plate portion constituting the upper surface of the housing, the acoustic vibration from the side surface of the speaker is directly emitted upward from the subtone hole. Since the sound emitted upward from the subtone hole is easy to hear by the performer located in front of the musical instrument, the missing component, particularly the high-frequency component, of the diffracted sound is compensated. For this reason, the high frequency range does not drop even on the performer side. Also, behind the instrument (for example, the audience side), the low frequency range is emphasized and the high frequency range passes well. Accordingly, it is possible to improve the acoustic characteristics at any position on the audience side and the performer side with a simple configuration in which a subtone hole is simply provided. In addition, the subtone hole is located in a predetermined position within the depth length range of the speaker so that the short side of the subtone hole made of a horizontally long hole is within the depth range, and the long side of the subtone hole is the length of the speaker. name a right angle to the sound emission axis, and a portion of the sub-tone hole forms a state where the center is shifted by a predetermined distance on the side surface side of the instrument from the sound emission axis center of the speaker of the sub tone holes of the speaker With the arrangement so as to be located above the side surface, the acoustic vibration from the speaker can be efficiently emitted upward, and the long side of the subtone hole is perpendicular to the sound emission axis of the speaker. The effect that it is easy to produce the spread of the sound to the right and left by the structure extended in the direction. In addition, since the subtone hole has a smaller area than the main tone hole, sound can be emitted upward at an appropriate volume through the subtone hole at an appropriate volume.

Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings.
Fig.1 (a) is a top view which shows the upper surface of an example of the electronic keyboard instrument which concerns on this invention, The rear view which looked at this electronic keyboard instrument from the arrow a is shown in FIG.1 (b). In addition, in the rear view shown in (b), the top and bottom are represented in reverse. A casing 1 of an electronic keyboard instrument according to the present embodiment includes a roof plate portion 2 forming a rear upper surface portion, a bottom plate portion 4 forming a bottom surface portion, left and right side plate portions 5a and 5b forming right and left side portions, and a back surface portion. The back plate part 7 which comprises and the mouth stick part 6 which comprises the front part. A keyboard part 3 is arranged on the front upper surface of the casing 1, and the internal mechanism of the keyboard part 3 is accommodated inside the casing 1. An operation panel 9 including various operation switches and the like is provided at a predetermined portion of the roof plate portion 2.

  In the housing 1, stereo left and right speakers 12a and 12b (shown by dotted lines in FIG. 1) are arranged at predetermined positions near the rear back plate 7 and the front surfaces of the speakers 12a and 12b. That is, the sound outlet is directed toward the rear plate portion 7 behind the musical instrument. As shown in FIG. 1B, the back plate 7 is provided with main tone holes 10a and 10b corresponding to the sound outlets on the front surfaces of the left and right speakers 12a and 12b, respectively. In the example shown in the figure, each main tone hole 10a, 10b is composed of a set of a plurality of long and small holes, and each set of the small holes substantially corresponds to the cone size of the speaker, that is, the size of the sound outlet. As described above, the speakers 12a and 12b are arranged with their front surfaces, i.e., sound emission ports, facing the main tone holes 10a and 10b corresponding to the speakers 12a and 12b, respectively, and the sound emitted from the front of the speakers is the main tone holes 10a and 10b. Sound is emitted to the rear of the instrument.

  In the roof plate 2, subtone holes 11 a and 11 b are formed at predetermined positions corresponding to the upper sides of the left and right speakers 12 a and 12 b, respectively. FIG. 2 shows an example of the positional relationship between the speaker 12a and the subtone hole 11a, and is a cross-sectional view taken along the line XX of FIG. In the illustrated example, a subtone hole 11a is formed above the core portion of the speaker 12a attached to the back plate portion 7. The same applies to the other subtone hole 11b. The upper surface of the subtone hole 11a is covered with a detachable saran net 13. For convenience of illustration, the saran net 13 is not shown in FIG. 1A and is shown by a one-dot chain line in FIG. A saran net mounting recess 14a is formed around the subtone hole 11a, and the saran net 13 is mounted thereon. The other subtone hole 11b is similarly formed with a saran net mounting recess 14b.

  As an example, the subtone holes 11a and 11b are formed as horizontally long holes as shown in FIG. 1A, and the center Q of the holes is appropriately shifted from the sound output axis S of the speaker. Preferably, as shown in the present embodiment, the center Q of the subtone hole may be shifted from the sound output axis S of the speaker by an appropriate distance d in the left and right side surfaces of the musical instrument. That is, the left subtone hole 11a is in the left direction in FIG. 1A, the right subtone hole 11b is in the right direction in FIG. 1A, and the center Q of the hole is the center of the speaker, that is, the sound emission axis S to d. Arranged so as to be shifted. It is preferable in terms of sound separation that the subtone holes 11a and 11b are provided apart from each other in the left-right direction. However, the present invention is not limited to this, and a subtone hole may be provided in an appropriate arrangement above the speakers 12a and 12b.

Sub tone holes 11a as shown in FIG. 1 (a), and 11b formed in the elongated hole, when the long side is to perpendicular to the sound emission axis S, Ru effectively der.
The predetermined portion corresponding to the side surface of the speaker in which the subtone holes 11a and 11b are to be provided in the roof plate 2 is preferably within the range of the depth length H of the speakers 12a and 12b, as shown in FIG. Thereby, the acoustic vibration from the speaker can be efficiently emitted upward. However, the present invention is not limited to this, and a subtone hole may be provided at a position somewhat deviated from this range.
The opening area of each subtone hole 11a, 11b is smaller than the area of the main tone hole 10a, 10b. For example, about ³ to 15 cm ² is generally used, and about 10 cm ² is preferable in view of sound emission performance and the like.

  The roof plate portion 2 is coupled to the back plate portion 7 via left and right and center partition plates 8a to 8c (shown by dotted lines in FIG. 1A). The plates 8a to 8c are combined holding plates for connecting and holding the roof plate portion 2 and the back plate portion 7, and only the plate 8b serves as a partition plate for sound separation. The left and right partition plates 8a and 8c are arranged closer to the side plate portions 5a and 5b than the left and right speakers 12a and 12b, and the central partition plate 8b is located between the speakers 12a and 12b. The partition plates 8 a to 8 c function as connection reinforcing members that connect the roof plate portion 2, the back plate portion 7, and the bottom plate portion 4. That is, as shown in FIG. 2 with respect to the central partition plate 8b, the partition plate 8b is coupled to the roof plate portion 2 at the upper end portion, and is coupled to the bottom plate portion 4 at the lower end portion. Although not shown, it is coupled to the back plate 7 at the rear end. The same applies to the other partition plates 8a and 8c. For the sake of convenience, in FIG. 2, the keyboard unit 3 is schematically shown by a two-dot chain line, and the detailed structure is not shown. The central partition plate 8b not only functions as the connection reinforcing member but also exhibits an excellent effect in acoustic separation between the left and right speakers 12a and 12b.

  With the above configuration, the front sound output ports of the speakers 12a and 12b are directed to the main tone holes 10a and 10b provided in the back plate portion 7, and the sound output from the front sound output ports is directed toward the rear of the instrument (for example, Sounded (in the direction of the audience). The sound from the front sound emission port is emitted toward the back of the instrument, but the low frequency range is easily diffracted, so that it resonates well even on the player side facing the keyboard portion 3 on the front of the instrument. Since the subtone holes 11a and 11b are formed in the roof plate portion 2 at positions corresponding to the upper sides of the left and right speakers 12a and 12b, acoustic vibrations from the side surfaces of the speakers are emitted upward from the subtone holes. . Since the sound emitted upward from the subtone holes 11a and 11b is easily heard by the performer located in front of the musical instrument, the missing component in the diffracted sound, particularly the high-frequency component, is compensated. For this reason, the high frequency range component that tends to be insufficient on the performer side is compensated for, and good acoustic characteristics can be obtained. Behind the musical instrument (for example, the audience side), all the components are emitted from the main tone holes 10a and 10b, and the acoustic characteristics are further improved by the acoustic components emitted from the sub tone holes 11a and 11b.

Although the present embodiment has been described above, the arrangement of the subtone holes 11a and 11b is preferably as close as possible to the speakers 12a and 12b. In an extreme case, the high sound range can be reached directly if there is no barrier on the roof plate part 2 or the back plate part 7, but the acoustic diaphragm is used to increase the low sound level by the roof plate part 2 or the back plate part 7. That doesn't work. Therefore, it is desirable that the subtone hole for directly reaching the vibration from the back surface of the speaker cone is closest to the cone.
Then, the upward arrow portion 2X of the cone 12P is good, but since the distance between the rear end face of the roof plate portion 2 and the subtone holes 11a and 11b becomes small and the strength cannot be maintained, the subtone hole 11a, The arrangement position of 11b was set above the core part 12M as shown in FIG.
Even in this case, the experimental results were good as described later.

  An actual measurement example of acoustic characteristics obtained according to the present embodiment will be described with reference to FIG. FIG. 3 shows an electronic keyboard instrument according to the present embodiment placed on a stand having a height of 1 m, and a microphone is installed at a height of about 45 cm above the center of the keyboard portion 3 and about 15 cm in front of the microphone. The frequency characteristic of the acoustic signal which collected the performance sound generated from the speakers 12a and 12b with the microphone is shown. Since the position of the microphone generally corresponds to the position of the performer's ear, the characteristic shown in FIG. 3 corresponds to the frequency characteristic of the performance sound heard by the performer. The vertical axis represents the sound pressure level, and the horizontal axis represents the frequency. According to FIG. 3, the sound pressure level shows a relatively high value between frequencies of about 200 to 400 Hz, but does not drop so much to about 4 kHz after that. For example, in the case of 88 keys of a piano, the sound range generated by the electronic keyboard instrument is about 27 Hz to about 4 kHz. Therefore, it can be understood that good frequency characteristics can be obtained over the entire required sound range.

  In the above embodiment, the main tone holes 10a and 10b are made up of a plurality of elongated small holes. However, the main tone holes 10a and 10b are not limited to this. In this case, the main tone hole may be covered with a saran net or the like.

  As described above, according to the present invention, it is possible to provide an electronic keyboard instrument having good acoustic characteristics at any position on the audience side and the performer side with a low-cost, compact and simple structure.

(A) is a top view which shows one Example of the electronic keyboard musical instrument which concerns on this invention, (b) is a rear view of the electronic keyboard musical instrument which concerns on the same Example. XX sectional drawing of Fig.1 (a). The graph which shows the example of an actual measurement of the frequency characteristic in the player side of the electronic keyboard instrument which concerns on the Example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Case 2 Roof board part 3 Keyboard part 4 Bottom board part 5a, 5b Side board part 6 Mouth stick part 7 Back board part 8a-8c Partition board 9 Operation panel 10a, 10b Main tone hole 11a, 11b Subtone hole 12a, 12b Speaker 13 Saran net 14a, 14b Saran net mounting recess

Claims (1)

An electronic keyboard comprising a keyboard portion provided near the front surface of the housing, a main tone hole provided on the back surface of the housing, and a speaker provided in the housing with the front surface facing the main tone hole In musical instruments,
In the roof plate part constituting the upper surface of the casing, a subtone hole made of a horizontally long hole is placed at a predetermined position within the range of the depth of the speaker so that the short side of the subtone hole is within the depth range. And the long side of the subtone hole is perpendicular to the sound output axis of the speaker, and the center of the subtone hole is shifted from the sound output axis center of the speaker by a predetermined distance toward the side of the instrument. And a portion of the sub-tone hole is positioned so as to be located above the side surface of the speaker, and the acoustic vibration of the high-frequency component from the speaker is efficiently emitted upward. An electronic keyboard instrument.

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