JP3692952B2 - Electronic instrument touch response device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a touch response device for an electronic musical instrument having a keyboard input means including a plurality of keys and an aftertouch sensor that generates an aftertouch output by a key pressing operation.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, in an electronic keyboard instrument, an after touch signal corresponding to a key pressing pressure at the time of key pressing is detected by an after touch sensor, and various musical tone elements such as a sound volume are controlled by the after touch signal. As this after-touch sensor, for example, a band-shaped sensor laid in the key arrangement direction under a plurality of keys is used to detect a force of pressing the band-shaped sensor with a key in response to a key pressing operation. In addition, as a belt-shaped sensor, a conductive rubber sandwiched between two electrodes (hereinafter referred to as “rubber-shaped sensor”) or a stack of two conductive sheets (hereinafter referred to as a “film-shaped sensor”). The former detects the volume change (resistance value change) of the conductive rubber pressed by the key, and the latter detects the contact area change (resistance value) of the conductive sheet pressed by the key. Change).
[0003]
[Problems to be solved by the invention]
However, the after-touch sensor (band sensor) is a sensor common to all keys. For example, even when a key is pressed with the same finger pressure, a single key is pressed and a plurality of keys are pressed simultaneously. Depending on the case, the aftertouch force (sum of the finger pressures) applied to the sensor is different, resulting in different aftertouch signals. For this reason, aftertouch may work even if you do not want to use aftertouch, or aftertouch may work more than necessary. There is a problem with sex.
[0004]
An object of the present invention is to improve aftertouch operability in a touch response device for an electronic musical instrument having a keyboard input means including a plurality of keys and an aftertouch sensor that generates an aftertouch output by a key pressing operation. To do.
[0005]
[Means for Solving the Problems]
An electronic musical instrument touch response device according to claim 1 of the present invention is an electronic musical instrument touch response device having a keyboard input means including a plurality of keys and an after touch sensor that generates an after touch output by a key pressing operation. based on the key depression speed of the plurality of keys, said a dead zone width setting means for setting a non-sensitive band width against the after touch force large in after-touch sensor, the number of the depressed as the number of key pressing is larger Sensing sensitivity setting means for setting the characteristics of the sensing sensitivity so as to reduce the sensing sensitivity of the after-touch sensor as the number of key presses increases, based on the set dead band width. It is characterized by.
[0006]
2. The touch response device for an electronic musical instrument according to claim 1, wherein “after-touch force” is a total weight (sensor input) applied to the after-touch sensor, and an output signal (for example, voltage) of the after-touch sensor depends on the after-touch force. It will be. Then, in a means (for example, an arithmetic expression) for converting the output signal into an after touch signal (after touch data), a dead band width of a predetermined width is set for the output signal from a value of zero. As the number increases, it increases. “Sensing sensitivity” is a gain in the means for converting the output signal of the after-touch sensor into an after-touch signal, and this sensing sensitivity decreases as the number of key depressions increases. Therefore, even when a plurality of keys are pressed at the same time, it is possible to suppress unnecessary aftertouch from being effective, as in the case where a single key is pressed . An aftertouch signal similar to that when one key is pressed by a key pressing operation can be obtained, and the aftertouch operability is improved.
[0011]
Incidentally, Oite to claim 1, the after-touch sensor, is stretched over a plurality of keys, sensor means (e.g., piezoelectric element) for detecting the bias of the tensioning means which is for each tensioned biasing of the key May be configured to generate the touch signal. When such a configuration is adopted, the tensioning means is stretched across a plurality of keys, and each of the keys is tensioned and biased, and this bias is detected by the sensor means and a touch signal is generated. Further, the tensioning means may be a string-like member in which a portion corresponding to the key is biased in a direction perpendicular to the tensioning direction by the operation of the key. With such a configuration, the following effects can be obtained. As for the string-like member, the part corresponding to the key is biased in the direction perpendicular to the tensioning direction (the arrangement direction of the plurality of keys) by the operation of the key, so the end of the string-like part is in the tensioning direction (due to the tension) Move to. Since the amount of movement of this end is very small compared to the amount of deviation of the part corresponding to the key, it is suitable to use a piezo sensor as the sensor means according to the configuration of claim 1. That is, since the amount of deviation of the part corresponding to the key can be detected with a small amount of movement of the end, a wide dynamic range can be obtained and the detection accuracy can be improved. The sensor means may be a pressure sensor. Furthermore, since the amount of movement of the end of the string-like member is very small, space is saved.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. First, a keyboard device as “keyboard input means” in the embodiment will be described. In the following drawings, the player side of the keyboard device is referred to as the front, and the opposite side is referred to as the rear.
[0013]
FIGS. 9, 10, and 11 are a plan view, a right side view, and a left side view, respectively, of an electronic piano keyboard device according to an embodiment of the present invention. In this keyboard apparatus, the entire key is supported by the keyboard frame 100, and the keyboard frame 100 is supported by the shelf board 101. The key 40 is composed of a white key and a black key. Each key has a rotation center R40 in the vicinity of the contact point with the support portion by a support portion 41 extending in the front direction slightly behind the center of the keyboard frame 100. It is supported so that it can rotate in the vertical direction. The mass body 50 is supported by the keyboard frame 100 below the key 40. The mass body 50 extends substantially horizontally in the front-rear direction as a whole, and the tip of the support piece 102 is formed by a support piece 102 erected at a position near the front of the keyboard frame 100 and a recess 51 for receiving the support piece 102. It rotates as a rotation center R50.
[0014]
In order to maintain the engagement state between the distal end portion of the support piece 102 and the recess 51, a spring composed of a recess formed on one side of the mass body 50 on the back side of the recess 51 in the mass body 50. The locking part 52 is pressed. The spring locking portion 52 is formed by a rib having a constant width in the thickness direction of the mass body 50, and a thin plate portion extends vertically in the center portion of the rib in the width direction in the spring locking portion 52. The end portion of the S-shaped spring 42 that engages with the spring locking portion 52 has a bifurcated shape having a slit in the center, and the thin plate portion is inserted into the slit for engagement.
[0015]
The middle portion of the S-shaped spring 42 is in contact with the edge of the spring through hole 103 at the approximately center in the front-rear direction of the upper part of the keyboard frame 100, and the other end of the S-shaped spring 42 is a spring at the lower rear of the key. It is comprised so that the receiving part 43 may be pressed. As a result, the S-shaped spring 42 acts to press the mass body 50 against the distal end portion of the support piece 102 at the position of the recess 52 and to push down the rear portion of the mass body 50 from the rotation center R50.
[0016]
The front end portion of the mass body 50 is in contact with the lower end portion of the hanging piece 44 of the key 40, and is rotated in conjunction with the key when the key 40 is pressed. A switch board 60 is supported by the keyboard frame 100 near the lower part of the front end of the mass body 50, and a key switch 61 formed of dome-shaped rubber is fixed on the switch board 60. On the lower surface of the front portion of the mass body 50, a switch drive unit 53 having a pair of legs extending downward at a position corresponding to the key switch 61 is provided. The switch driving unit 53, the switch board 60, and the key switch 61 constitute a key pressing switch that senses the key pressing speed by using a conduction start time difference at the time of key pressing due to a difference between two contact distances in the key switch 61. ing.
[0017]
The mass body 50 extends to the rear portion of the keyboard frame 100 and is supported in the vicinity of the rear end portion by a felt stopper member 104 fixed on the keyboard frame 100 in the rest position (non-key-pressed state). When the key 40 is depressed, the mass body 50 moves from the rest position indicated by the solid line in FIGS. 10 and 11 to the key depression position indicated by the alternate long and short dash line. A stopper member 105 is held immediately behind the key 40 in the keyboard frame 100 and serves to stop the mass body 50 that has reached the key pressing position. The stopper member 105 covers the cushioning felt 105a with a protective sheet 105b, and the contact portion 54 at the rear end of the mass body 50 presses the buffering felt 105a through the protective sheet 105b. The cushioning felt 105a is usually configured by overlapping felts having different stiffnesses so as to provide a buffering action against a collision of the rear end portion of the mass body 50 and a reliable stop feeling with respect to the player's fingers. The mass body 50 is made of plastic from the front part to the vicinity of the rotation center R50, and is formed so that a metal bar extends from the rear part. The mass of the metal bar extending backwards causes inertia at the time of key depression. Causes resistance.
[0018]
A sensor device 70 is attached to the rear part of the keyboard frame 100. The sensor device 70 generally has a structure in which two tension members are supported on both sides of the keyboard. Of the two tension members, one tension member 71 is used for sensing, and is held between the cushioning felt 105a of the stopper member 105 and the protective sheet 105b and extends toward the front of the keyboard device. Yes. The other tension member 72 is for compensation provided in order to prevent a decrease in sensitivity of the tension member 71 for sensing due to a disturbance factor. The compensation tension member 72 extends in parallel with the sensing tension member 71 at a position slightly away from the stopper member 105 so as not to contact the mass body 50.
[0019]
A tension portion 70A supported by the keyboard frame 100 is provided outside the left end of the keyboard row. The tension portion 70 </ b> A includes a holding member 73 fixed to the keyboard frame 100 and a tension plate spring 74 attached to the holding member 73. The leaf spring 74 extends rearward from the holding member 73 and is then folded back to form a V shape. A small groove is formed at the free end of each leaf spring 74, and one end of each of the sensing tension member 71 and the compensation tension member 72. It supports to pull the part.
[0020]
A detection unit 80 supported by the keyboard frame 100 is provided outside the right end of the keyboard row. The detection unit 80 has a structure in which a detection leaf spring 82 extends from the detection circuit board 81. The detection leaf spring 82 is in the form of a leaf spring, the base end portion is fixed to the detection circuit board 81 with screws 88, 88, and the distal end portion is formed with a small groove to pull the end portion of the sensing tension member 71. I support it. A strain sensor 83 is attached near the base end of the detection leaf spring 82. In this example, the strain sensor 83 is configured using a piezo element. The detection circuit board 81 is provided with a circuit (not shown) for detecting an output signal from the strain sensor 83 and an adjustment element 84 for fine adjustment thereof. The circuit is further connected to a circuit to be described later (electronic keyboard musical instrument microcomputer). Further, the end of the compensation tension member 72 on the right side of the keyboard row is fixedly supported by the keyboard frame 100.
[0021]
In the sensor device 70, the following settings are further made. The tension plate spring 74 is stronger than the detection plate spring 82. Further, the tension member 72 for compensation has a higher tensile rigidity than the tension member 71 for sensing. That is, the compensation tension member 72 is fixedly supported at the right end by the keyboard frame 100 and pulled at the left end by the tension leaf spring 74 to be in a predetermined extended state. On the other hand, the sensing tension member 71 is held at the left end position in FIG. 9 together with the compensation tension member 72 and the tension plate spring 74 as a joint holding portion. Further, the right end is held at the free end of the detection leaf spring 82 so as to bend the detection leaf spring 82. Therefore, in order to stabilize the position of the left end in a state where the compensation tension member 72 is pulled, the tension force of the tension leaf spring 74 is increased so that the detection leaf spring 82 is not greatly bent. The tensile rigidity of the tension member 72 is increased.
[0022]
Next, the operation of this keyboard apparatus will be described. 10 and 11 show a pause state before key depression. When the key is pressed from this state, the key 40 rotates downward about the rotation center R40, and the hanging piece 44 pushes down the mass body 50. Accordingly, the mass body 50 rotates about the rotation center R50, and the switch driving unit 53 moves downward toward the key switch 61. The switch driving unit 53 of the mass body 50 is in contact with the key switch 61, turns on the key pressing switch, and operates the sound generation mechanism to generate sound. During this time, the mass body 50 raises the rear part from the rotation center R50. Immediately after the switch drive unit 53 comes into contact with the key switch 61, the abutment portion 54 at the rear end of the mass body 50 abuts against the stopper member 105, whereby the rotation of the mass body 50 and the key 40 is stopped. .
[0023]
The sensor device 70 operates as follows. When the key pressing force is increased or decreased in the key pressing state, the abutting portion 54 at the rear end of the mass body 50 changes the amount of bending of the stopper member 105, particularly the buffer felt 105a. The sensing tension member 71 is held between the buffer felt 105a of the stopper member 105 and the protective sheet 105b. Therefore, when the bending amount of the buffer felt 105a changes, the meandering amount of the sensing tension member 71 accompanying the bending also changes. When the amount of meandering increases, the distance between the ends of the sensing tension member 71 decreases, and accordingly, the bending of the detection leaf spring 82 increases. Therefore, the output of the strain sensor 83 increases. By picking up this output change, it is possible to detect a change in the pressing force applied to the key after the key is pressed. If the volume, sound quality, etc. are changed accordingly, after-touch control can be performed. By appropriately selecting the flexibility of the buffer felt 105a and the protective sheet 105b of the stopper member 105, the bending of the stopper member 105 due to each key pressing can be extended for sensing even when a plurality of keys are pressed. Reflecting on the meandering of the member 71, accurate aftertouch control can be performed.
[0024]
However, the extending member used in the sensor device is a long member straddling both ends of the keyboard row. Therefore, the change in length due to disturbance factors such as temperature and humidity after being attached to the keyboard device also becomes large. If the end of the tension member for sensing is fixed to the keyboard frame, the linear expansion coefficient of the tension member itself and the expansion coefficient of the keyboard frame itself disturb the distortion amount of the strain sensor due to disturbance factors. End up. Therefore, it is necessary to deal with these disturbance factors for accurate aftertouch control.
[0025]
The sensor device 70 of this embodiment uses two tension members, and a sensing tension member 71 is provided in parallel to the compensation tension member 72. The tension member 72 is stretched by applying the spring force of the tension plate spring 74 to the compensation tension member 72, and the sensing tension member 71 is the same as the compensation tension member 72 on the tension plate spring 74. In a state where one end is supported at the position, the sensing tension member 71 itself receives the spring force of the detection leaf spring 82. Therefore, even if a disturbance factor acts, the influence is absorbed by the compensating tension member 72, and the spreading to the sensing tension member 71 is prevented. That is, even if expansion heat is generated due to a temperature rise after being attached to the keyboard device, the support point by the tension plate spring 74 is moved by the amount of extension of the tension member. Since the amount of thermal expansion is the same between the compensation tension member 72 and the sensing tension member 71, one end is supported at the position of the tension leaf spring 74 moved by the extension of the compensation tension member 72. The sensing tension member 71 does not affect the other end of thermal expansion. This compensation action is similarly performed with respect to the influence of humidity between the compensation tension member 72 and the sensing tension member 71 having the same elongation rate due to humidity. Depending on the external force at the time of attachment, the tension length of the tension member may change. On the other hand, the influence can be reduced by increasing the tensile rigidity of the compensating tension member 72.
[0026]
Further, the sensing tension member 71 has a portion corresponding to the key that is biased in a direction perpendicular to the tension direction (a direction in which a plurality of keys are arranged) by operating the key. Moves in the tensioning direction (due to tension). Since the amount of movement of the end portion, that is, the amount of bending of the detection leaf spring 82 is very small compared to the amount of deviation of the portion corresponding to the key, it is suitable to use a piezo element as the strain sensor 83. That is, since the amount of deviation of the part corresponding to the key of the sensing tension member 71 can be detected by the slight amount of deflection of the detection leaf spring 82, a wide dynamic range can be obtained and the detection accuracy can be improved. Furthermore, since the amount of bending of the detection leaf spring 82 is very small, the space is saved.
[0027]
Next, an embodiment of an electronic keyboard instrument to which the present invention is applied will be described.
FIG. 3 is a block diagram of the electronic keyboard instrument of the embodiment. The CPU 1, RAM 2 and ROM 3 constitute a microcomputer, and the CPU 1 controls the entire instrument using the working area of the RAM 2 based on a control program stored in the ROM 3. The keyboard device 4 is the keyboard device shown in FIGS. 9 to 11, and includes an aftertouch sensor 5 including a key 40, a key switch 61, the distortion sensor 83, and a detection circuit board 81.
[0028]
CPU1 calculates a after-touch data as described below from the output data of the after-touch sensor 5, the after-touch data is output to the selector 6, the selector 6 in accordance with the after-touch data, tone color, sound volume, vibrato depth, etc. The effect control signal for various effect control is output to the sound source 7, and this effect control signal is selected by, for example, operating a digital volume of the various controls 8. The sound source 7 includes an effect circuit, and generates a tone signal with various effects according to the effect control signal. The musical sound signal is converted into an analog signal by the D / A conversion circuit 9 and amplified by the amplifier 10, and a musical sound is generated by the speaker 11.
[0029]
The key switch 61 is a contact time difference type two-make switch having two contacts (hereinafter referred to as a first switch and a second switch), and first the first switch is closed ( ON) and then the second switch is closed. A contact time difference at this time (a value of a timer counter TC (n) described later) is output to the sound source 7 together with a key code and a key-on signal as initial touch data. In the key release stroke, the second switch is opened (off), and then the first switch is opened. The closing / opening events of the first switch and the second switch are detected by the CPU 1 as key events. Further, when the output of the after touch sensor 5 exceeds a predetermined threshold, the after sensor is turned on. When the output of the after touch sensor 5 becomes less than the predetermined threshold, the after sensor is turned off. Detected.
[0030]
FIG. 4 is a diagram showing an example of the key buffer set in the RAM 2. In this embodiment, the sound source 7 has 16 sound generation channels, and 16 channel key buffers having channel numbers n of “0 to 15” are provided. The key buffer for each channel includes a register for storing key code data (KCD), a register for storing key event type data, a register for storing timer counter value TC (n) or aftertouch data af (n), and keystrokes These registers are configured to store state data indicating various states. Then, the CPU 1 writes and reads (references) various data to the key buffer.
[0031]
There are six types of key event type data: first switch on, second switch on, after sensor on, after sensor off, second switch off, and first switch off, as 3-bit numeric data corresponding to each event. Remembered. Further, as shown in FIG. 5, the state data is stored as four types of numerical data “00”, “01”, “10”, and “11” according to the key stroke. Note that the aftertouch data af (n) obtained from the aftertouch sensor 5 when the output of the aftertouch sensor 5 exceeds a predetermined threshold is also referred to as an “AF sensor value”.
[0032]
Next, the operation of the embodiment will be described based on a flowchart.
FIG. 6 is a flowchart of main processing executed by the CPU 1. First, initialization processing is performed in step S1, timbre selection processing, musical tone parameter setting processing, and the like are performed in step S2. In step S3, FIG. Performs key release processing. Next, in step S4, processing for selecting the effect control signal of the selector 5, that is, processing for changing the control target of aftertouch (AF), is performed according to the operation of the various operators 7. Then, the process returns to step S2.
[0033]
In the key pressing / releasing process of FIG. 7, it is determined in step S11 whether there is any key event. If there is no key event, the process returns to the original routine and returns to the original routine. If there is a key event, step S12 is performed. Then, it is determined by referring to the key buffer whether there is already a channel of the key code (KC) in which the key event has occurred, and if there is a channel of the same key code, the process proceeds to step S14. If there is no channel with the same key code, in step S13, it is determined whether or not there is an empty channel by referring to the key buffer (or sound source). If there is, the process proceeds to step S14. In step S14, a channel to be processed for the key code of the currently generated key event is determined, and the process proceeds to step S15.
[0034]
In step S15, the key code corresponding to the current key event and the type of key event are written in the n channel (n is the channel number of the determined channel) of the key buffer, and the process proceeds to step S16. In step S16, the type of the current key event is determined, and processing in steps S17 to S21 is performed according to the type of each key event to return to the original routine. If the second switch is off, the original routine is restored.
[0035]
If the first switch is on, in step S17, the state “01” indicating the start of the timer count is set in the register of the state of the “n” channel portion of the key buffer, and the value of the timer counter TC (n) is reset. . The timer counter TC (n) is counted by a timer interrupt process shown in FIG. If the second switch is on, in step S18, the value of TC (n) and the key-on in the “n” channel portion of the key buffer are sent to the sound source 7, the state is set to “10”, and TC (n ) Is reset. If the second switch is off, the process returns to the original routine as it is. If the first switch is off, the key off is output to the sound source 7 together with “n” (channel number) in step S19, and “n” in the key buffer is output. The state of the channel part is set to “00”, and all the data of the “n” channel part of the key buffer is cleared together with the channel number “n”.
[0036]
With the above processing, when the second switch is turned on (step S18), TC (n) is output as initial touch data together with the key code and key-on to the sound source 7, and the generation of the musical tone is started. Further, when the first switch is turned off (step S19), a key-off is output to the sound source 7 and the sound is muted. Note that the sound source 7 starts mute by key-off input, but the sound waveform envelope is attenuated by the start of mute and is completely muffled when the level falls below a predetermined level.
[0037]
When an after touch operation is performed when a key is pressed, an after sensor on key event occurs between the time when the first switch is turned on and the time when the first switch is turned off. When the after sensor is ON, in step S20, the AF sensor value obtained from the after touch sensor 5 is taken in place of TC (n) in the “n” channel portion of the key buffer, and the state is set to “11”. If the after sensor is off, the AF sensor value in place of TC (n) in the “n” channel portion of the key buffer is reset in step S21.
[0038]
The timer interrupt process of FIG. 8 performs a count process of the timer counter TC (n), an AF sensor value fetching process, and a sending process of aftertouch data to the sound source. Touch data is calculated.
[0039]
First, in step S31, "0" is set in the register n for key buffer channel scan, and in step S32, the n channel state data in the key buffer is searched. Next, in step S33, it is determined whether or not there is step S “x1” in the n channels of the key buffer. Note that “x” in the state represents “0 or 1”. If the state “x1” does not exist, the process proceeds to step S36. If the state “x1” exists, it is determined in step S34 whether “x1” of the channel of the state “x1” is “11”. If “x1” is “11”, the process proceeds to step S38, and if “x1” is not “11”, the process proceeds to step S35. In step S35, the value of the register TC (n) corresponding to the state “01” in “n” of the key buffer is incremented by “1” and stored in the register TC (n) (counting up), and step S36. Proceed to In step S36, it is determined whether or not n is the maximum value. If it is not the maximum value, the channel number n is incremented by "1" in step S37 and the process returns to step S32. If n is the maximum value, the process proceeds to step S41. move on. In step S41, all the channels in the key buffer are searched, and as a result, it is determined whether or not there is a channel of state “11”. If there is no channel of state “11”, the process returns to the original routine. If there is a channel of state "11", the process proceeds to step S42.
[0040]
If “x1” of the channel in the state “x1” is “11” in step S34, the value of the after-touch sensor (in the TC (n) / af register of the “n” channel of the key buffer in step S38 ( AF sensor value) is captured, and it is determined in step S39 whether n is the maximum value. If not, the channel number n is incremented by "1" in step S40 and the process returns to step S32, where n is the maximum. If it is a value, the process proceeds to step S42.
[0041]
In Step S42, the last AF sensor value (af value) in all channels is taken into the register af, and the process proceeds to Step S43. That is, when a plurality of keys are pressed, the AF sensor value is obtained from the after touch sensor 5 for each key press, but since these values (AF sensor values) are updated for each key press, The incoming AF sensor value is captured. Next, in step S43, the number K (number of key presses) of the state "11" is extracted for all the channels of the key buffer. In step S44, (K−1) × C1 + C2 is calculated from the number K and predetermined constants C1 and C2, and the calculation result is stored in the register W. Next, in step S45, (1-a * (K-1)) * af-b * W is calculated from the value (W) of the register W, the AF sensor value af, the number K, and the constants a and b. The calculated value is stored in the register AF. However, the range is 0 <AF ≦ 0xff (0xff: upper limit set value). In step S46, the value of the register AF is output as aftertouch data to the sound source 7, and the process returns to the original routine. In addition, the meaning of each said formula is mentioned later.
[0042]
Next, the above process will be described based on a typical operation flow at the time of key depression. When the first switch is turned on by pressing the key, the timer counter TC (n) is reset in step S17 and the state becomes “01”. Therefore, in the interrupt process of FIG. 8, the process goes through steps S33 and S34 in step S35. TC (n) is incremented. If a plurality of keys are pressed, this procedure is similarly performed corresponding to each key (channel). Since the state is not “11” in step S41, TC (n) is sequentially counted up in the next interrupt process.
[0043]
When the key is depressed and the second switch is turned on, the sound generation process for the sound source 7 is executed in step S18 and the state becomes “10”, so that no substantial process is performed in the interrupt process of FIG. Steps S33 → S36 → S41 → Return).
[0044]
When the after sensor is turned on and the after sensor is turned on, the AF sensor value is fetched in step S20 and the state becomes "11". Therefore, in the interrupt processing of FIG. 8, after steps S33 and S34, AF is performed again in step S38. The sensor value is taken into the key buffer. If a plurality of keys are pressed, this procedure is similarly performed corresponding to each key (channel). In step S42, the last AF sensor value in all the channels is fetched as the AF sensor value af to be calculated, and in step S43, the number of channels in the state “11” in the key buffer, that is, the key depression. A number K is obtained, and aftertouch data is calculated in steps S44 and S45.
[0045]
If the key is released and the first switch is turned off, the mute process is executed in step S19 and the state becomes “00”, and no substantial process is performed in the interrupt process of FIG. 8 (steps S33 → S36 → S41 → Return). In this embodiment, when the after sensor is turned off, the state remains “11” in step S21. That is, even after the after sensor is turned off, the state “11” is maintained until the first switch is turned off thereafter. Therefore, even after the after touch operation is interrupted, the after touch operation can be performed again immediately until the key is released (until the first switch is turned off). Aftertouch operability is improved.
[0046]
Next, the following formulas (1) and (2) will be described in step S44 and step S45.
W = (K−1) × C1 + C2 (1)
However, K: Number of key presses (number), C1 and C2: Predetermined constant AF = (1−a × (K−1)) × af−b × W (2)
(0 <AF ≦ 0xff)
Where af: AF sensor value, a and b: constants
“W” in Expression (1) is a dead band width near zero with respect to the AF sensor value, and the relationship between the number of key presses K and the dead band width W is shown in FIG. 2A. The calculation of the expression (1) is executed when the key pressing number K is “1” or more (“16” or less), and the dead zone width W increases as the key pressing number K increases. That is, the dead zone width increases as the number of pressed keys increases.
[0048]
(1−a × (K−1)) in the equation (2) is the gain G, and the relationship between the number of key presses K and the gain G is shown in a graph as shown in FIG. The calculation of this equation (1) is also executed when the key pressing number K is “1” or more (“16” or less), and the key pressing number K is “1” and the gain G is also “1”. When the number K of key presses increases, the gain G decreases. Note that the maximum value of the number K of key presses is “16”, and the constant a is set so that the gain G becomes a predetermined positive value (a constant value) when K = 16. In other words, the gain (sensing sensitivity) decreases as the number of pressed keys increases.
[0049]
In addition, “AF” in Expression (2) is aftertouch data output to the sound source 7, and the relationship between the AF sensor value af in Expression (2) and the aftertouch data AF is shown in a graph in FIG. become that way. Then, by setting the aftertouch data AF calculated from the AF sensor value af according to the expression (2) within a range of 0 <AF ≦ 0xff, the AF sensor value af corresponding to the weight applied to the aftertouch sensor 5 is obtained. The output characteristics of the aftertouch data AF are as shown in FIG. FIG. 1 shows the case where the key depression number K is small by a solid line, and the case where the key depression number K ′ is large by a broken line. When the key depression number is large, the dead band width W ′ is larger than the dead band W. In addition, the gain G ′ corresponding to the inclination is smaller than the gain G.
[0050]
As described above, the dead band width W increases as the number of key presses K increases. Therefore, even when a plurality of keys are pressed at the same time, as in the case where a single key is pressed, unnecessary after-sales are performed. It is possible to suppress the touch from working. Further, since the gain G decreases as the number K of key presses increases, even when a plurality of keys are pressed at the same time, the same aftertouch as when a single key is pressed by a plurality of key press operations. Data can be obtained.
[0051]
In the above embodiment, the after-touch sensor has been described as generating an after-touch signal by biasing a string-like member (sensing tension member). However, as the after-touch sensor, the above-described rubber-like sensor or film-like sensor is used. It may be a sensor.
[0052]
In the above embodiment, both the dead band width W and the gain G are changed according to the key depression number K. However, only one of the dead band width W and the gain G is varied according to the key depression number K. May be changed. In this case, the operability is not as good as when both are changed, but the operability is better than when both the dead zone width and the gain are fixed.
[0053]
【The invention's effect】
As described above, according to the touch response device for an electronic musical instrument according to the first aspect, even when a plurality of keys are simultaneously pressed, an unnecessary aftertouch is performed as in the case where a single key is pressed. Can be suppressed, and aftertouch signals similar to those obtained when a single key is depressed by a plurality of key depression operations can be obtained, and the aftertouch operability is improved. .
[Brief description of the drawings]
FIG. 1 is a diagram illustrating an output characteristic of aftertouch data with respect to an AF sensor value of an aftertouch sensor according to an embodiment of the present invention.
FIG. 2 is a graph showing the relationship between the number of key presses and dead band width, the graph between the number of key presses and gain, and the graph between the AF sensor value and aftertouch data AF in the embodiment of the present invention. is there.
FIG. 3 is a block diagram of an electronic keyboard instrument according to an embodiment of the present invention.
FIG. 4 is a diagram illustrating an example of a key buffer in the embodiment of the present invention.
FIG. 5 is a diagram showing a relationship between a key stroke and a state in the embodiment of the present invention.
FIG. 6 is a flowchart of main processing according to the embodiment of the present invention.
FIG. 7 is a flowchart of key press / release processing according to the embodiment of the present invention.
FIG. 8 is a flowchart of a timer interrupt process according to the embodiment of the present invention.
FIG. 9 is a plan view of a keyboard device for an electronic piano according to an embodiment of the present invention.
FIG. 10 is a right side view of the electronic piano keyboard device.
FIG. 11 is a left side view of the electronic piano keyboard device.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... CPU, 2 ... RAM, 3 ... ROM, 4 ... Keyboard apparatus (keyboard input means), 5 ... After touch sensor, 7 ... Sound source

Claims (1)

In an electronic musical instrument touch response device having a keyboard input means comprising a plurality of keys and an aftertouch sensor that generates an aftertouch output by a key pressing operation,
Based on the number of key presses of the plurality of keys, a dead band width setting unit that sets a large dead band width for the after touch force in the after touch sensor as the number of key presses increases ,
Sensing sensitivity setting means for setting the characteristics of the sensing sensitivity so as to reduce the sensing sensitivity of the after-touch sensor as the number of key presses increases based on the number of key presses and the set dead band width;
Touch response apparatus of an electronic musical instrument characterized by comprising a.

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