JP4529827B2 - Electronic keyboard instrument - Google Patents

Description

  The present invention relates to an electronic keyboard instrument that generates a musical sound by vibrating a soundboard.

  Conventionally, electronic keyboard instruments have been improved so that the generated musical sounds are close to natural musical sounds with a sense of expanse like an acoustic musical instrument, but there is still a difference from acoustic instruments in terms of hearing. .

  In natural musical instruments, this can be heard not only by the sound produced by vibrating members such as strings, but also by resonating with the abutment sounds of the parts in the musical instrument and by the respective parts and soundboards when the operating elements such as keys are driven. This is because there are many sounds generated by the complex action of sounds and the like, and existing electronic keyboard instruments cannot fully express such complicated sounds.

  For example, some sounds are generated in response to a performance operation, and each sound is generated from a speaker as a performance sound. However, it may be complicated depending on the situation (keyboard or pedal operation status, operation timing, etc.). There are limits to the reproduction of pronunciation in the working environment, and there are cases where expressions are insufficient.

On the other hand, there is also known an electronic keyboard instrument in which a transducer (vibrator) is attached to a soundboard and the soundboard is vibrated to output a complicated resonance sound (Patent Documents 1 and 2 below).
Japanese Patent No. 2917609 Japanese Patent Laid-Open No. 5-80748

  However, electronic keyboard instruments using transducers as described in Patent Documents 1 and 2 are still under development, and there is room for improvement in terms of transducer placement and the like in order to obtain a sufficient sound output with good sound quality. .

  The present invention has been made in order to solve the above-described problems of the prior art, and an object of the present invention is to efficiently vibrate the soundboard to achieve natural sound with good sound quality and rich volume. To provide electronic keyboard instruments.

Electronic keyboard instrument according to claim 1 of the present invention in order to achieve the above object, it has a soundboard made of a plate-like member, an electronic keyboard musical instrument for generating musical tones by vibrating a該響plate, frame A fixed holding portion that fixes and holds a peripheral portion of the soundboard to the frame; and at least one vibrator that is attached to the soundboard and vibrates the soundboard. When the soundboard is vibrated a plurality of times with different frequencies while being fixed by the fixed holding part, and the nodal lines at each frequency generated on the soundboard are superimposed, the density of the nodal lines is rough. The at least one vibrator is arranged at such a position.

  According to the present invention, it is possible to efficiently vibrate the soundboard and realize natural sound with good sound quality and rich volume.

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

  FIG. 1 is a block diagram showing the overall configuration of an electronic keyboard instrument according to an embodiment of the present invention. FIG. 2 is a plan view of the electronic keyboard instrument. FIG. 3A is a front view of the electronic keyboard instrument, and FIG. 3B is a cross-sectional view of one attachment portion with respect to the frame of the soundboard.

  As shown in FIG. 1, the electronic keyboard instrument 1 includes a detection circuit 3, a detection circuit 4, a ROM 6, a RAM 7, a timer 8, a display device 9, a storage device 10, an external interface (external I / F) 11, and a sound source circuit 13. And the effect circuit 14 are connected to the CPU 5 via the bus 16.

  Further, a performance operator 15 is connected to the detection circuit 3, and the performance operator 15 includes a keyboard 17 composed of a plurality of keys for inputting pitch information, and a damper pedal (hereinafter referred to as a performance pedal) operated with feet. 18) (referred to as "pedal"). A panel operator 2 including a plurality of switches for inputting various information is connected to the detection circuit 4. The display device 9 is composed of a liquid crystal display (LCD) or the like, and displays various information such as musical scores and characters. A timer 8 is connected to the CPU 5, and an external performance device 100 is connected to the external I / F 11. A sound generator 20 is connected to the effect circuit 14 via a sound system 19. The sound system 19 includes a DAC (Digital-to-Analog Converter), an amplifier, and the like.

  The detection circuit 3 detects the operation state of the performance operator 15, and the detection circuit 4 detects the operation state of the panel operator 2. The CPU 5 controls the entire electronic keyboard instrument 1. The ROM 6 stores a control program executed by the CPU 5, various table data, and the like. The RAM 7 temporarily stores various input information such as performance data and text data, various flags, buffer data, calculation results, and the like. The timer 8 measures the interrupt time and various times in the timer interrupt process. The storage device 10 stores various application programs including the control program, various music data, various data, and the like.

  The external I / F 11 has MIDII / F and various communication I / Fs. For example, a MIDI (Musical Instrument Digital Interface) signal from an external device such as the external performance device 100 is input, or a MIDI signal is input to the external device. Or output to The tone generator circuit 13 converts the performance data input from the performance operator 15 or preset performance data into a musical sound signal. The effect circuit 14 gives various effects to the musical tone signal input from the sound source circuit 13.

  The storage device 10 includes, for example, a hard disk drive (HDD). In addition, the storage device 10 can read and write data from and to an external storage medium 12. Examples of the storage medium 12 include a flexible disk drive (FDD), a CD-ROM drive, a magneto-optical disk (MO) drive, and the like.

  The sound generation unit 20 includes a plurality of (for example, three) transducers 21 (transducers 21A, 21B, and 21C), and vibrates (excites) the soundboard 33 shown in FIG. 2 based on performance data or operation of the performance operator 15. ) To generate sound. In other words, the electronic keyboard instrument 1 does not include a speaker, and the sound is produced exclusively by the vibration of the soundboard 33.

  As shown in FIG. 3A, the pedal 18 is provided at the lower front part of the leg body 30, and a frame 31 is fixed to the upper part of the leg body 30. As shown in FIG. 2, a keyboard 17 is arranged on the player side (front side) in the same manner as a grand piano. The soundboard 33 is disposed behind the keyboard 17. As shown in FIG. 2, the soundboard 33 has a plan view shape similar to that of a soundboard disposed under a string in a grand piano. The soundboard 33 is a wooden board having a thickness of about 1 cm and is formed to have a uniform thickness. The depth of the soundboard 33 is shorter on the high sound side (right side in FIG. 2) than on the low sound side (left side in FIG. 2). Note that the soundboard 33 can be appropriately changed in the design as long as it is suitable for vibrating and sounding, regardless of the material.

  The planar view shape of the frame 31 is a frame shape that substantially follows the peripheral edge of the soundboard 33. Specifically, the outline of the frame 31 is slightly smaller than the peripheral portion of the soundboard 33 and has a similar shape to the soundboard 33. As shown in FIGS. 2 and 3B, the soundboard 33 is fixedly held on the upper end of the frame 31 via a rubber plate member 32 by a plurality of screws 34 with appropriate intervals.

  The transducers 21A, 21B, and 21C are disposed on the upper surface of the soundboard 33 so as to be separated from each other. The transducer 21A is disposed on the low sound side of the soundboard 33, the transducer 21B is disposed on the middle sound range of the soundboard 33, and the transducer 21C is disposed on the high sound side of the soundboard 33 in a region having a short depth. With respect to the position in the front-rear direction, the transducer 21C is located at the foremost position, and the transducer 21B is located at the rearmost position. Each transducer 21A, 21B, 21C is arranged at a position where the soundboard 33 can be vibrated efficiently, and a specific method for determining the arrangement location will be described later.

  Each transducer 21 is directly attached to the soundboard 33. As for the attachment to the soundboard 33, any means such as screwing or adhesion may be used. The structure of the transducer 21 is a known structure as described in FIG. 1 or FIG. 2 on page 266 of the March 1971 issue of radio technology, and vibrates itself by an electric signal (performance signal or drive signal). Then, the soundboard 33 is vibrated by a reaction due to its own weight. The transducer 21 may have any structure as long as the sound board 33 can be vibrated and sounded by an electric signal.

  In the present embodiment, transducers 21A and 21B have the same configuration. The transducers 21A and 21B are large in size, have a low frequency that can be handled, and have particularly good vibration efficiency in the vicinity of a frequency of 250 Hz. For higher frequencies, the generated vibration is minute. In addition, the intensity of vibration that can be generated is strong, and it is mainly responsible for low-frequency sound generation.

  On the other hand, the transducer 21C is different from the transducers 21A and 21B in characteristics (capability), that is, vibration efficiency with respect to an input signal. The transducer 21C is smaller than the transducers 21A and 21B, has a high frequency that can be handled, and can efficiently excite the frequency of 1000 Hz or more. Further, the intensity of vibration that can be generated is not as strong as that of the transducers 21A and 21B, and is mainly responsible for high-frequency sound generation.

  FIG. 4 is a block diagram showing functions of the electronic keyboard instrument 1. The signal processing unit 40 shown in the figure includes, as function units, first and second performance signal generations 22 and 23, first and second performance data 24 and 25, effect processing 26, delay processing 27, an adder 28, and an output. It has a distribution 29. The functions of these functional units of the signal processing unit 40 are components such as the CPU 5, the ROM 6, the RAM 7, the timer 8, the storage device 10, the external interface 11, the sound source circuit 13, the effect circuit 14, and the sound system 19 shown in FIG. This is realized through collaboration.

  The first performance data 24 is waveform data obtained by sampling musical tones that are generated when each key is operated without pressing the damper pedal in an acoustic grand piano. On the other hand, the second performance data 25 is waveform data obtained by subtracting the data corresponding to the first performance data 24 from the sampled musical sounds produced by operating each key while depressing the damper pedal. . That is, the first performance data 24 is data for reproducing a normal performance sound. The second performance data 25 is data for reproducing a damper sound having a sense of spaciousness due to resonance of strings other than the string being struck when a damper pedal is operated in an acoustic piano. These are stored in the ROM 6, for example.

  The first performance signal generator 22 generates a first performance signal using the first performance data 24 in response to the key release operation of each key on the keyboard 17 and sends it to the effect processing 26. On the other hand, the second performance signal generator 23 generates a second performance signal using the second performance data 25 according to the operation of the pedal 18 and the keyboard 17 and sends the second performance signal to the delay processing 27. The first performance signal sent to the effect processing 26 is subjected to a set effect in the effect processing 26, while the second performance signal sent to the delay processing 27 is subjected to a predetermined delay processing in the delay processing 27. The first and second performance signals after these processes are added / mixed by the adder 28 and sent to the output distribution 29.

  The output distribution 29 distributes the output to the transducer 21 based on the supplied mixed signal. That is, an analog drive signal is generated, amplified and output for each of the transducers 21A, 21B, and 21C. Specifically, a drive signal that vibrates at a frequency corresponding to the pitch and a strength corresponding to the velocity is generated and output. At that time, regarding the output balance, the output level of the transducer 21C among the three transducers 21 is increased for the mixed signal with high pitch, and the transducer 21A / 21B is set for the mixed signal with medium / low pitch. By increasing the output level, the sound field localization is matched to the operated key as much as possible.

  In addition, the output balance of the drive signal based on the first performance signal and the drive signal based on the second performance signal generated by a certain key operation is the same between the transducers 21, but is output with a separate balance for each transducer 21. May be.

  FIG. 5 is a flowchart of the main process. This process is started when the power is turned on.

  First, initialization is executed, that is, execution of a predetermined program is started, and initial values are set in various registers such as the RAM 7 to perform initial setting (step S101). Next, input from the panel operator 2 is confirmed (step S102), and device settings (volume, tone, effect setting, etc.) corresponding to the input are executed (step S103). Then, it is determined whether or not there is an input from the performance operator 15 (step S104). If there is no input, the process proceeds to step S105. If there is an input, it is instructed to press the key (the key of the keyboard 17). It is determined whether or not (pressed) (step S106).

  As a result of the determination, if it is not a key pressing instruction, it is determined whether or not it is a key release instruction (step S110), and if it is not a key release instruction, it is determined whether or not the pedal 18 is turned on ( If the pedal 18 is not turned on in step S113), the pedal 18 is turned off, and the process proceeds to step S115. Accordingly, if the input of the performance operator 15 is a key depression instruction, steps S107 to S109 are executed. If the key release instruction is a key release instruction, steps S111 and S112 are executed, and the pedal 18 is turned on. Step S114 is executed. If the pedal 18 is turned off, step S115 is executed and the process proceeds to Step S105.

  First, in step S107, it is determined whether or not the pedal 18 is currently on. If the pedal 18 is not in the on state, the process proceeds to step S 109, where the first performance data 24 corresponding to the pitch of the key press (key pressed) is read from the ROM 6 and based on the first performance data 24. Then, a first performance signal having an envelope corresponding to the key depression velocity is generated. On the other hand, if the pedal 18 is on, the process proceeds to step S108, where the second performance data 25 corresponding to the pitch of the key depression key is read, and a second performance signal having an envelope corresponding to the key depression velocity is generated. Then, the step S109 is executed.

  In step S111, it is determined whether or not the pedal 18 is currently on. If the pedal 18 is not in the on state, the process proceeds to step S112, and the performance signal of the key released (key released) is stopped. That is, a mute signal is generated in order to mute the corresponding musical tone being generated. In this process, the first performance data 24 is read, and a first performance signal for muting having an envelope corresponding to the key release operation is generated. On the other hand, if the pedal 18 is on, the process proceeds to step S105 without stopping the performance signal.

  In step S114, if there is a key being pressed and a sound is being generated, a second performance signal corresponding to the key being pressed is generated in response to an on operation of the pedal 18. That is, the second performance data 25 corresponding to the pitch of the key in the depressed state is read, and a second performance signal having an envelope that matches the sound attenuation state during the sound generation process is generated.

  In step S115, if there is a sound being generated at a pitch corresponding to a key other than the key being pressed, the performance signal corresponding to the tone is stopped. That is, a mute signal is generated in order to mute the corresponding musical tone being generated. In this process, the first performance data 24 and the second performance data 25 corresponding to the pitches other than the key being pressed and corresponding to the pitch being sounded are read out and the pedal 18 is turned off according to the off operation. A mute first performance signal and a second performance signal having an envelope are generated.

  In step S105, based on the generated first performance signal and second performance signal, the drive signals are individually considered in consideration of the characteristics and arrangement of the transducers 21 so as to be localized according to the pitch. Is generated and output. As a result, the soundboard 33 vibrates at a frequency corresponding to the pitch, and a performance sound or a damper sound is generated. Thereafter, the process returns to step S102.

  The musical sound due to the vibration of the soundboard 33 is closer to the reproduction of the sound in a complicated working environment depending on the operation state of the keyboard 17 and the pedal 18 and the operation timing thereof, compared with the musical sound by the speaker, and the sound quality is good. Natural sound. In particular, since the soundboard 33 has the same shape as the soundboard of a grand piano, its sound is similar to that of a live piano. In particular, since the shape of the frame 31 in plan view is a frame shape that substantially follows the periphery of the soundboard 33, the soundboard 33 vibrates greatly (at a sufficiently low frequency) in the inner region of the frame 31. Therefore, it is possible to satisfactorily reproduce the sound and the damper sound in the low sound range. In addition, since the transducer 21 is disposed at a position where the soundboard 33 can be vibrated efficiently, a sufficient sound output can be obtained.

  Here, with regard to sound quality control, for example, even if the sound has the same pitch and volume, the sound quality can be changed to some extent by changing the drive signal output to each transducer 21. As for the sound quality setting, an input is accepted by the panel operator 2 in step S102 of FIG.

  Next, a method for determining the placement location of the transducer 21 will be described.

  FIGS. 6A to 6D are diagrams showing nodal lines generated when the soundboard 33 is vibrated at a certain natural frequency. FIGS. 4A to 4D show on the monitor screen the outline line 33x and the nodal line corresponding to the outline of the soundboard 33 when the soundboard 33 is vibrated at different natural frequencies. is there.

The placement location of the transducer 21 is determined by the following steps (i) to (V).
(I) A fine granular material such as sand is dispersed on the soundboard 33, and the soundboard 33 is freely vibrated while gradually changing the frequency.
(Ii) Since the particulate matter on the soundboard 33 gathers at the nodal line when it matches the natural frequency of the soundboard 33, the position of the nodal line is grasped for each natural frequency from the aggregate state of the particulate matter at that time. To do.
(Iii) A nodal line for each natural frequency is superimposed on a plane corresponding to the soundboard 33.
(IV) Specify a location where the density of the superimposed nodal lines is “rough”.
(V) The place where the density of the nodal line is “coarse” is determined as the placement position of the transducer.

  In the step (i), for example, the soundboard 33 is vibrated by gradually changing the frequency stepwise up to a frequency of about 50 to 400 Hz. At that time, the configuration and the fixed state of the soundboard 33 are determined, and conditions other than the frequency are not changed. In the steps (i) to (iii), the sound board 33 may be actually vibrated as described above, and the nodal line may be grasped by visual observation or detection. However, in this embodiment, instead of actually vibrating the soundboard 33, the above steps (i) to (iii) are performed by computer analysis.

  In the computer analysis, in step (i), information such as the size, shape, thickness, material, material density, Young's modulus, Poisson's ratio, screw 34 position, etc. of the soundboard 33 is previously set as a fixed condition. Enter it. In step (ii), the monitor screen of the computer is set as a plane corresponding to the soundboard 33, and the outline 33x and the nodal lines at the respective natural frequencies obtained by the analysis are displayed on the monitor screen. 6A to 6D illustrate some of them, and the natural frequencies of those vibrations are, for example, 50, 140, 260, and 360 Hz.

  Then, in the step (iii), as shown in FIG. 7, the superposed node lines at the respective natural frequencies are displayed on the monitor screen of the computer. Then, in the step (iV), the overlapped nodal line group shown in FIG. 7 is visually observed, and the portion where the density of the nodal line is coarse and the dense portion are known, so the coarse portion is specified (for example, (Indicated with white circles in the figure). Next, in the step (V), the position on the soundboard 33 corresponding to the rough position on the monitor screen is specified, and this position is set as the placement candidate position of the transducer 21. Here, although it is assumed that a sufficiently larger number than three placement candidate positions is specified, after that, each transducer 21 is installed at the placement candidate position, and the soundboard 33 is actually vibrated, The best combination of positions may be selected.

  However, there are some points to be noted regarding the placement of the transducer 21. First, it arrange | positions in the position suitable for the characteristic of each transducer 21. FIG. That is, it is desirable that the large (for low sound) transducers 21 (21A, etc.) be arranged in the left half of the soundboard 33, and the small (for high sounds) transducer 21 (21C, etc.) in the right half. Further, in order to appropriately control the sound field localization, at least two of the transducers 21 need to be separated from each other in the left-right direction.

  Further, in the front-rear direction, the middle / low-frequency transducer 21 is not arranged on the front side of the soundboard 33. That is, they have large shaking due to their low frequency, and may give the user an unpleasant feeling when the vibration is excessively transmitted. On the other hand, the risk of the high sound transducer 21 is small. Moreover, the high-frequency transducer 21 is preferably on the side closer to the player from the viewpoint of clarifying the localization. Therefore, it is desirable that the foremost part of the plurality of transducers 21 is arranged on the highest sound side (right side).

  The arrangement mode of the transducer 21 shown in FIG. 2 described above is made in consideration of these. The position of the transducer 21 is a position that avoids the positions of the frame 31 and the screw 34 inside the frame 31 in plan view. When the soundboard 33 is vibrated at a certain natural frequency, a nodal line is generated. However, when the soundboard 33 is vibrated at the same frequency, it is inefficient to vibrate the nodal line position. The portion where the nodal line group becomes rough as a result of vibration at various frequencies is a position where vibration can be made relatively efficiently even when vibrations of all frequencies occur, and the transducer 21 is disposed at that position. It is a thing.

  As shown below, for the above computer analysis, in order to further simplify the identification of the location where the nodal line group is rough, a geometric identification method can be employed with the position of the screw 34 to the frame 31 as a condition. It is.

  FIG. 8A is a schematic diagram showing a passing point through which the position of the screw 34 and the nodal line pass. FIG. 8B is a schematic diagram showing the position of the frame 31 and the passing point through which the nodal line passes.

  First, as shown in FIG. 6A, as an example, a point Q1 that is an intermediate point (1/2) between the screw 34 (1) and the screw 34 (2), and the screw 34 (1) and the screw 34 are shown. Points Q2 and Q3 that are at a distance of 1/3 and 2/3 from the screw 34 (1) with respect to (2), respectively. These points Q1, Q2, and Q3 are at positions obtained by dividing the distance between the screw 34 (1) and the screw 34 (2) by an integer.

  Similarly, points Q4 to Q6 are obtained between the screw 34 (1) and the screw 34 (3). Also, in each combination of the other two screws 34, the same points as the points Q1, Q2, and Q3 are required. These processes can also be performed by a computer process.

  Here, since the nodal line does not vibrate up and down, even if the nodal line position is vibrated, the soundboard 33 cannot be vibrated efficiently. As for the position of the screw 34, the nodal line passes in vibrations at any frequency, but it is considered that the nodal line easily passes at the position of the point Q that is divisible by the integer as described above. Accordingly, not only the position of the screw 34 but also a position avoiding these points Q is determined as a position where the nodal density becomes coarse, and is determined as a placement candidate for the transducer 21. By the way, even if the position on the frame 31 is a position where the screw 34 does not exist, a large number of the points Q exist between the adjacent screws 34, so that the nodal line easily passes.

  On the other hand, in FIG. 8B, when the entire upper end surface of the frame 31 is in contact with the soundboard 33, for example, a rubber plate member 32 (see FIG. 3B) is provided over the entire upper end of the frame 31. This is assumed. In this case, between an arbitrary point P1 on the frame 31 and a point P2 on the frame 31 that faces the point P1 (for example, a point that bisects the area of the region in the frame 31) (see FIG. Similarly to the example of a), a point Q (Q7, Q8, Q9) that is divisible by an integer is obtained. Similarly, the point Q (Q10, Q11, Q12) is also determined between the next arbitrary point P3 and the point P4 opposite thereto. In this way, the point Q is determined between as many arbitrary points as possible and the points opposed thereto. Similarly to the above, positions where these points Q are avoided are determined as placement candidates for the transducer 21.

  In the examples of FIGS. 8A and 8B, the positions of 1/2, 1/3, and 2/3 between the two points are set as the point Q. The position (1/4, 3/4, etc.) divided as described above may be added to the point Q.

  By the way, the vibration of the soundboard 33 is close to the piston vibration in the low sound range, and when the nodal line is vibrated, the vibration of the soundboard 33 becomes weak. On the other hand, in the high sound range, point-weighted and complicated vibration is generated, and even if the excitation position is slightly deviated from the arrangement candidate position, the vibration efficiency is not significantly reduced. Therefore, particularly for the transducer 21 in charge of bass, it is desirable to strictly set the placement position to the placement candidate position.

  In order to generate a sound in a rich frequency band, it is necessary that the transducer 21 arranged so as to avoid the position of the screw 34 and the position of the frame 31 is present, and more preferably at a position where the nodal density is coarse. It is important that a transducer 21 is present.

  According to the present embodiment, the transducer 21 is arranged at a position that is neither the position of the screw 34 nor the position of the frame 31 in the plan view of the soundboard 33, and in particular, each sound that occurs when the soundboard 33 is freely vibrated. Since it is arranged at a position where the density of the nodal line group at the natural frequency is coarse, it is possible to efficiently vibrate the soundboard and realize natural sound in a rich frequency band with good sound quality. .

  Further, the transducers 21A and 21B and the transducer 21C have different characteristics, and these are arranged at positions corresponding to the characteristics. Depending on the characteristics and arrangement positions of the transducers 21 and the operation of the performance operator 15, each transducer is arranged. Since the drive signal is generated and output individually for each 21, the subtle soundboard vibration control by the output of each transducer is possible, and natural sound in a rich frequency band is realized and sound quality adjustment is facilitated. be able to.

  Moreover, since the sound board 33 has the same shape as the sound board of a grand piano, a natural sound close to that of a grand piano can be realized. In particular, when a bass is vibrated by vibrating the board, a larger area is required compared to the treble sound, so the shape of the soundboard 33 is ideal for reproducing piano sounds.

  In this embodiment, in order to reproduce the piano sound more appropriately, the soundboard 33 has a piano soundboard shape. However, the soundboard 33 may have any shape for simple sound generation. In order to produce a more appropriate sound, it may be appropriately selected according to the type of sound to be produced. For example, when playing a violin sound, an ideal pronunciation can be expected if it is configured in the shape of a violin.

  In the present embodiment, in the generation of the drive signal, first and second performance signals are first generated (steps S109, S112, S114, and S115 in FIG. 5), which are effect processing 26 and delay processing 27. After the processing, the output distribution 29 (see FIG. 4) generates three drive signals respectively output to the transducers 21A, 21B, and 21C (step S105 in FIG. 5). However, the present invention is not limited to this, and an output distribution function is provided in the stage before the processing of the effect processing 26 and the delay processing 27, and driving based on the operation of the keyboard 17 is individually performed for each transducer 21A, 21B, 21C. A signal and a drive signal based on the pedal 18 may be generated.

  In the present embodiment, the transducer 21 is attached to the upper surface of the soundboard 33, but may be attached to the lower surface. The transducers 21A and 21B may have different characteristics. The number of transducers 21 may be at least one if the sound field localization control is not performed and the sound is simply generated. However, from the viewpoint of obtaining good sound quality, it is preferable to provide at least two transducers. There may be four or more.

It is a block diagram which shows the whole structure of the electronic keyboard musical instrument which concerns on one embodiment of this invention. It is a top view of this electronic keyboard instrument. It is a front view (figure (a)) of an electronic keyboard musical instrument, and sectional drawing (figure (b)) of one attachment part with respect to the flame | frame of a sound board. It is a block diagram which shows the function of an electronic keyboard instrument. It is a flowchart of a main process. It is a figure which shows the nodal line produced when a soundboard is vibrated with a certain natural frequency. It is the figure which made the nodal line in each frequency when vibrating a soundboard superimposed and displayed on the monitor screen. It is a schematic diagram (figure (a)) which shows the passing point where a screw position and a nodal line pass, and a schematic diagram (figure (b)) which shows a passing point where a frame position and a nodal line pass.

Explanation of symbols

  1 Electronic keyboard instrument, 21 Transducer (vibrator), 31 Frame, 33 Soundboard, 34 Screw (fixed holding part)

Claims (2)

An electronic keyboard instrument having a soundboard made of a plate-like member and generating a musical sound by vibrating the soundboard,
And frame,
A fixed holding portion for fixing and holding a peripheral portion of the soundboard to the frame;
And at least one vibrator attached to the soundboard for vibrating the soundboard,
In the state where the soundboard is fixed to the frame by the fixing holding portion, the soundboard is vibrated a plurality of times with different frequencies, and the nodal lines at each frequency generated on the soundboard are superimposed. An electronic keyboard instrument, wherein the at least one vibrator is arranged at a position where a line density is coarse. 2. The electronic keyboard instrument according to claim 1, wherein the vibrator is arranged at a position that is neither the position of the frame nor the position of the fixed holding portion in a plan view of the soundboard.

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