Electronic percussion instrument with a net-like material to minimize noise

An object of the present invention is to provide a percussion detecting apparatus, which is excellent in percussion feeling, and the percussion sounds of which are very small, in electric percussion instrumental system. The percussion detecting apparatus is provided with a head prepared from a net-like raw material composed of a first net and a second net, and the net-like raw material being obtained by such a manner that both are nets having been woven in accordance with plane weaving manner wherein the longitudinal and traverse fibers cross at right angles are laminated in such a way that the weave patter directions thereof intersect obliquely with each other; and a head sensor which is in contact with the center position of the under side in the head and detects percussion with respect to the head as electric signal.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates to an electronic percussion instrumental 
system and a percussion detecting apparatus in the electronic percussion 
instrumental system, and more particularly to an electronic percussion 
instrumental system which simulates a percussion instrument such as 
acoustic drum sounding musical tone as a result of percussing it with 
sticks or the like by a player and a percussion detecting apparatus in the 
electronic percussion instrumental system. 
2. Description of the Related Art 
Heretofore, in an electronic percussion instrumental system such as 
electronic drum simulating acoustic drum, a percussion detecting apparatus 
provided with a surface to be percussed being generally called by the name 
of "percussion pads" is utilized as a means for detecting percussion. 
As such a percussion detecting means as described above, for example, the 
percussion detecting apparatus disclosed in Japanese Patent Laid-open No. 
44357/1996 has been known. In the percussion detecting apparatus disclosed 
in Japanese Patent Laid-open No. 44357/1996, the percussion surface is 
formed by covering a plate-like case with a material of a soft 
high-molecular compound 
However, in such percussion detecting apparatus wherein the percussion 
surface is formed by covering the plate-like case with a soft 
high-molecular compound material, there is such a problem that repulsive 
feeling at the time of percussing the percussion surface is remarkable, so 
that good percussion feeling cannot be obtained. In addition, the above 
described percussion detecting apparatus involves also such a problem that 
there is a fear of disturbing the performance by the percussion sound, 
because the percussion sound generated at the time when the percussion 
surface is percussed is significant. 
On one hand, it has been proposed to utilize, as a percussion detecting 
means, a percussion surface, the tension of which can be adjusted and is 
called by the name of "head" in acoustic drum, which is further provided 
with a sensor for detecting percussion. 
In the present, specification, adjustment for tension of a percussion 
surface which is adjustable as in the head of acoustic drum will be called 
by the term "tuning". 
In the case when the head of acoustic drum is served for a percussion 
detecting means as described above, there is such a problem that although 
percussion feeling is excellent in this case because the head for the 
acoustic drum is utilized as it is, the percussion sound becomes 
remarkable so that it disturbs the performance. 
OBJECT AND SUMMARY OF THE INVENTION 
The present invention has been made in view of the problems as described 
above involved in the prior art. Accordingly, an object of the present 
invention is to provide a percussion detecting apparatus provided with a 
head as the percussion surface which is excellent in percussion feeling 
and in which the percussion sound is extremely quiet in an electronic 
percussion instrumental system. 
Furthermore, another object of the present invention is to provide an 
electronic percussion instrumental system which is adapted to be easily 
capable of correct tuning of the head in the case when the head is tuned 
on the basis of an indication which is suitably given and corresponding to 
a position of percussion in the head. 
Moreover, still another object of the present invention is to provide an 
electronic percussion instrumental system which is adapted to be capable 
of detecting a correct position in percussion by correcting variations in 
tension of the head as a result of tuning of the same. 
An yet further object of the present invention is to provide an electronic 
percussion instrumental system which is adapted to make clear a position 
of percussion in the head in case of tuning operation to display the 
tuning state, whereby the tuning operation can be carried out while 
confirming the state, so that anybody can easily conduct such tuning 
operation without requiring any sense of skilled user. 
In order to achieve the above described objects, the present invention is 
characterized by a percussion detecting apparatus in electronic percussion 
instrumental system comprising a head the percussion surface of which is 
composed of a net-like raw material; and a percussion detecting means 
being in contact with the center position of the aforesaid head and 
detecting percussion with respect to the aforesaid head as electric 
signal. 
Therefore, in accordance with the present invention, since the percussion 
surface of the head is composed of a net-like raw material, extremely good 
percussion feeling can be obtained because of the elasticity of the 
net-like raw material. Besides, since air passes through the openings of 
stitches in the net-like raw material, percussion sound in case of 
percussing the head becomes extremely small. 
Furthermore, the present invention is characterized by an electronic 
percussion instrumental system which detects percussion as electric signal 
and generates musical tone based on the electric signal thus detected 
comprising a head the percussion surface of which to be percussed is 
tunable; a percussion detecting means for detecting percussion upon the 
aforesaid head as electric signal; a means for detecting a position of 
percussion point for performing arithmetic computations by inputting the 
electric signal detected by means of the aforesaid percussion detecting 
means to detect percussion point positional information; and a display 
means for effecting a display corresponding to the percussion point 
positional information detected by the aforesaid means for detecting a 
position of percussion point. 
Therefore, in accordance with the present invention, since a display 
corresponding to the percussion point positional information is effected 
by means of the display means, the head can be tuned while observing 
visually the resulting display, so that correct tuning of the head can 
easily be realized. 
Moreover, the present invention is characterized by an electronic 
percussion instrumental system comprising further an arithmetic 
computation compensating means for compensating the arithmetic 
computations in the aforesaid means for detecting the position of 
percussion point in response to a tuning state of the aforesaid head. 
Therefore, in accordance with the present invention, the arithmetic 
computations for detecting the percussion point positional information in 
response to tuning of the head are compensated, the position of percussion 
point is also compensated in response to tuning of the head, whereby it 
becomes possible to display the correct position of percussion point. 
Still further, the present invention is characterized by an electronic 
percussion instrumental system which detects percussion as electric signal 
and generates musical tone based on the electric signal thus detected 
comprising a tunable head; a means for detecting a position of percussion 
point for detecting the position of percussion point upon the aforesaid 
head; and a display means for effecting a display in response to the 
results detected by the aforesaid means for detecting the position of 
percussion point; a percussion point positional mark for tuning being 
provided on the aforesaid head. 
Therefore, in accordance with the present invention, since a tuning 
operation can be conducted by a user in accordance with such a manner that 
a place marked with a percussion point positional mark is percussed by the 
user, and the result detected at that time by the position of percussion 
point detecting means is confirmed while watching the display means, 
tuning operation can simply be carried out without relying upon user's 
sense.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
An example of manner of practice of the electronic percussion instrumental 
system and the percussion detecting apparatus in the electronic percussion 
instrumental system according to the present invention will be described 
in detail hereinafter in conjunction with the accompanying drawings. 
FIG. 1 is a constitutional block diagram showing an example of manner of 
practice of the electronic percussion instrumental system according to the 
present invention wherein the electronic percussion instrumental system 
comprises a percussion detecting apparatus 10 provided with a head sensor 
14 functioning as a percussion detecting means for detecting percussion 
applied to a head 12 the surface of which is composed of a net-like raw 
material which will be described hereunder, and a rim-shot sensor 18 for 
detecting percussion applied to a rim 16; an analog-to-digital (A/D) 
converter 20 which performs analog-to-digital conversion of the detected 
signals output from the head sensor 14 and the rim-shot sensor 18 in 
time-sharing manner and inputs the converted signals to a DSP 22 which 
will be mentioned hereinafter; the DSP 22 which detects the percussion 
applied to the head 12, the intensity thereof the position of 
percussion-from the detected signals which are derived from the head 
sensor 14 and which were input from the analog-to-digital converter 20 as 
well as performance by means of a brush, and in addition, the DSP 
detecting also the percussion applied to the rim 16 and the intensity 
thereof from the detected signals which are derived from the rim-shot 
sensor 18 and which were input from the analog-to-digital converter 20 to 
supply the results thus detected to a CPU 24 which will be described 
hereunder; the CPU 24 which supplies the output from the DSP 22 to a sound 
source IC 34, which will be undermentioned, wherein the output is 
converted into required performance information, as well as detects 
operations of a group of operation keys 30 which will be mentioned 
hereinafter, and controls the DSP 22; a read only memory (ROM) 26 storing 
a program or the like which is to be executed by the CPU 24, a random 
access memory (RAM) 28 functioning as a working area required for 
executing the program by means of the CPU 24; the group of operation keys 
30 including mode selecting keys for setting normal performance mode, 
brush performance mode or tuning mode, keys for selecting tone color or 
setting level or the like, and the like keys; a display unit 32 for 
displaying an operation mode selected by a key in the group of operation 
keys 30, tone colors required for the tone color selection, and a tuning 
state in case of tuning mode; the sound source IC 34 which reads a 
waveform memory 36 which will be undermentioned on the basis of 
performance information from the CPU 24 to form digital musical tone 
signals and outputs the signals thus formed to a digital-to-analog (D/A) 
converter 38 which will be described hereunder; the waveform memory 36 
storing sampling waveform data for forming the musical tone signals; and 
the digital-to-analog converter 38 for converting digital musical tone 
signals supplied from the sound source IC 34 into analog musical tone 
signals to output the signals thus converted to a sound system composed of 
an amplifier, a speaker and the like. 
Then, the constitution of the percussion detecting apparatus 10 will be 
described by referring to FIG. 2 being a perspective view showing the 
percussion detecting apparatus 10 and FIG. 3 being a sectional view taken 
along the line III--III of FIG. 2. 
The percussion detecting apparatus 10 contains a cylindrical barrel section 
50, and around the outer circumference of the barrel section 50 are formed 
protrusively engaging portions 52 each having a tapped hole (not shown) 
provided with a thread groove (not shown) with a prescribed interval along 
the diametrical direction of the barrel section. Into the engaging portion 
52 is screwed an engaging pin 54 on which is formed a thread ridge to be 
combined with the thread groove formed on the engaging portion 52, so that 
the head 12 and the rim 16 are fixed to the barrel section 50 through the 
engaging pin 54. Furthermore, a locking projection 54a for locking the rim 
16 is formed on the engaging pin 54. 
The head 12 is prepared as shown in FIGS. 4 and 5 in such a manner that a 
net-like raw material composed of a first net 56 and a second net 58, each 
of which is woven in accordance with plane weave wherein the longitudinal 
and transverse fibers cross at right angles, are laminated to one another 
so as to cross obliquely their longitudinal and transverse weave pattern 
directions, and the net-like raw material thus arranged is bonded to a 
frame 60. It is to be noted herein that the expression "the weave pattern 
direction of the first net 56 crosses obliquely that of the second net 58" 
means that when the first net 56 wherein the longitudinal and transverse 
fibers cross at right angles is superposed on the second net 58 wherein 
the longitudinal and transverse fibers cross at right angles, adjacent 
fibers in the first net 56 and the second net 58 thus superposed intersect 
with each other at an angle .alpha. which is smaller than 90 degrees as 
shown in FIG. 6. 
Moreover, on the top of the head 12 is provided a percussion point 
positional mark M which is formed with a circular contour by means of 
printing as shown in FIG. 20 and which is used in case of tuning 
operation. 
Furthermore, the rim 16 is prepared by integrally molding a metallic 
material and is composed of a flange portion 66 which is positioned around 
the outer circumference of the rim and has hole potions 64 into each of 
which an engaging pin 54 can be inserted, and a rim percussion portion 68 
which is ascendingly formed and extended from the flange portion 66 around 
the inner circumference thereof. The top of the rim percussion portion 68 
is covered with a covering member 70 made from an elastic material such as 
rubber, sponge and the like. 
A manner for fixing the head 12 and the rim 16 to the barrel section 50 
each of them having the structure described above is such that the head 12 
is first put on the barrel section 50, then, the rim 16 is put on the head 
12, and the positions of them are adjusted in such a way that each hole 
portion 64 of the rim 16 communicates with each tapped hole defined on 
each engaging portion 52 of the barrel section 50. Thereafter, each 
engaging pin 54 is inserted into each hole portion 64 of the rim 16 as 
well as into each tapped hole defined on each engaging portion 52 of the 
barrel section 50, and the thread ridge of each engaging pin 54 is 
threadedly combined with the thread groove in each engaging portion 52 of 
the barrel section 52, so that the head 12 and the rim 16 are forcedly 
fixed to the barrel section 50 by means of the locking projection 54a of 
each engaging pin 54. 
More specifically, with the progress of screwing each engaging pin 54 in 
the tapped hole in each engaging portion 52 of the barrel section 50, the 
flange portion 66 of the rim 16 is pressed downwards in FIG. 3 by means of 
each locking projection 54a, so that the frame 60 of the head 12 is also 
pressed downwards through the flange portion 66. As a result, the first 
net 56 and the second net 58 the downward movement of which are restricted 
by an upper end portion 50a of the barrel section 50, respectively, are 
stretched over the barrel section 50 with a prescribed tension. Thus, when 
an amount of screwing each engaging pin 54 in each tapped hole defined on 
each engaging portion 52 of the barrel section 50 is adjusted, the tension 
of the first net 56 and the second net 58 can be arbitrarily controlled, 
whereby tuning of the head 12 can be carried out. 
Furthermore, a head sensor supporting material 72 is placed in the barrel 
section 50 in such that the head sensor supporting material 72 intersects 
the position of the axial center of the barrel section 50. A head sensor 
14 is bonded to the top of the head sensor supporting material 72 at the 
central portion thereof by means of a cushioning double-coated tape 78 
which will be described hereinafter so as to be in contact with the second 
net 58. In other words, the head sensor 14 is disposed on the under 
surface of the net-like raw material composed of the first net 56 and the 
second net 58 in the head 12 at the center thereof in contact therewith. 
As shown in FIGS. 7(a), 7(b), and 7(c), the head sensor 14 is provided with 
a disc-shaped piezoelectric element 76 containing wires for output signal 
74, and to the under surface of the piezoelectric element 76 is bonded the 
cushioning double-coated tape 78. A diameter of the cushioning 
double-coated tape 78 is made to coincide with an node diameter of the 
piezoelectric element 76. 
Furthermore, to the top of the piezoelectric element 76 is bonded a 
frustoconical cushioning member 80 made from an elastic material such as 
rubber, sponge and the like. The cushioning member 80 has a bottom surface 
of a larger diameter than that of the piezoelectric element 76, the cross 
section of which tapers off upwardly, and it is in contact with the second 
net 58 at the extreme end of the cushioning member 80 of a thin diameter. 
Moreover, in the vicinity of the rim percussion portion 68 disposed on the 
upper portion inside the barrel section 50 is bonded the rim-shot sensor 
18 by means of the cushioning double-coated tape 78. The rim-shot sensor 
18 is provided with the disc-shaped piezoelectric element 76 containing 
wires for output signal 74, and to the under surface of the piezoelectric 
element 76 is bonded the cushioning double-coated tape 78. The diameter of 
the cushioning double-coated tape 78 is made to coincide with the node 
diameter of the piezoelectric element 76. 
Namely, in the electronic percussion instrumental system according to the 
present invention, a member obtained by removing the cushioning member 80 
from the head sensor 14 is used as the rim-shot sensor 18, whereby 
improvements in efficiency of parts to be used are intended. 
In this electronic percussion instrumental system, a variety of heads 12 
having different diameters as well as a variety of the barrel sections 50 
being adapted for such various heads and the like members are prepared, 
whereby a size of the head 12 is suitably changed. 
In the constitution as described above, when the head 12 is percussed with 
a stick 100 (see FIG. 8), the head sensor 14 detects the percussion, while 
when the rim 16 is percussed with the stick 100 (see FIG. 9, but it is to 
be noted that both the head 12 and the rim 16 are percussed with the stick 
100 in FIG. 9), the rim-shot sensor 18 detects the percussion. Further, 
when the head 12 is brushed or percussed with a brush 102 (see FIG. 10), 
the head sensor 14 detects the contact of the brush 102 with the head 12. 
In these circumstances, when the head 12 is percussed with the stick 100, 
extremely good percussion feeling closely resembling the percussion 
feeling in the case when the head of an acoustic drum is percussed can be 
obtained because of the elasticity of a net-like raw material composed of 
the first net 56 and the second net 58. 
In addition, since the first net 56 and the second net 58 which have been 
woven in accordance with plane weaving manner wherein the longitudinal and 
transverse fibers cross at right angles are laminated obliquely with each 
other in the net-like raw material, the tension is uniformized over the 
whole surface of the net-like raw material, so that there is little 
variations in percussion feeling due to differences in the position 
percussed, and as a result, output waveforms from the head sensor 12 
become the ones which are easily processed. 
As described above, performance played by percussing the head 12 is 
controlled by output waveforms from the head sensor 14 being in contact 
with the under surface of the center in the first net 56 and the second 
net 58 of the head 12. In this respect, since the head sensor 14 is 
positioned at the center of the first net 56 and the second net 58 of the 
head 12, variations in output waveforms due to differences in the position 
of the head 12 percussed become concentric circular form, so that 
variations in tone color simulating acoustic drum are easily expressed. 
Moreover, since the cushioning member 80 of the head sensor 14 is in 
contact with the under surface of the center of the second net 58 of the 
head 12, oscillation of the head 12 attenuates rapidly so that the output 
signal attenuates also rapidly, whereby erroneous detecting operation in 
case of percussing the head 12 in a rapid and repeated manner is 
prevented. 
Further, since the cushioning member 80 bonded to the top of the 
piezoelectric 76 of the head sensor 14 is in contact with the second net 
58 of the head 12 at the site of the frustoconical extreme end portion 
having a thin diameter and a small area, vibrations of percussion in the 
head 12 are hardly transmitted directly to the piezoelectric element 76, 
so that damage of the piezoelectric element 76 is suppressed. 
In addition, since a diameter of the cushioning double-coated tape 78 
bonded to the under surface of the piezoelectric element 76 is made to be 
equal to the node diameter, sensitivity of the piezoelectric element 76 
increases, so that delicate variations in the oscillation due to 
differences in positions percussed can be more precisely detected. 
Still further, since air passes through openings of stitches in the 
net-like raw material composed of the first net 56 and the second net 58, 
percussion sound in the case when the head 12 is percussed is extremely 
small. Such percussion sound in case of percussing the head 12 is 
dependent upon a ratio of openings in the net-like raw material composed 
of the first net 56 and the second net 58, and therefore, the higher ratio 
of openings brings about the smaller percussion sound. However, an 
excessive ratio of openings results in low tension of the first net 56 and 
the second net 58 so that the percussion feeling deteriorates. 
Accordingly, it is preferred to suitably keep a balance between the 
percussion feeling and the ratio of openings. 
Yet further, since the rim 16 is covered with the covering member 70, the 
percussion sound in case of percussing the rim 16 is also reduced. 
In this respect, the oscillation in case of percussing the rim 16 is mostly 
transmitted to the barrel 50, the performance played by percussing the rim 
16 can be controlled in accordance with output waveforms in the rim-shot 
sensor 18 attached to the barrel 50. 
In the following, electrical processing contents in the electronic 
percussion instrumental system according to the present invention will be 
described by referring to the accompanying flowcharts. 
FIG. 11 is a flowchart of the main routine executed by the CPU 24 wherein 
when the power is turned on, first, memories, registers and the like are 
initialized (step S802). 
Then, it is judged which operational mode has been set, i.e., it is judged 
whether a tuning mode which changes percussion feeling of the head 12 by 
adjusting tension in the net-like raw material of the head 12, or a normal 
performance mode which sounds percussion instrumental sounds by detecting 
percussion upon the head 12 and percussion upon the rim 16, or a brushing 
performance mode which sounds percussion instrumental sounds by detecting 
either brushing or percussing the head 12 with the brush 102 has been 
established (step S804) by supervising an operational state of mode 
selecting keys of the group of operation keys 30. 
As a result, when it has been judged that the tuning mode had been set in 
the step S804, the DSP 22 is set to the tuning mode, whereby the DSP 22 is 
adapted to be set so as to execute the DSP percussion signal processing 
routine shown in FIG. 12 (step S806). Thereafter, the tuning processing 
routine executed by the CPU 24 shown in FIG. 17 is executed (step S808), 
then, processing for stopping the tuning mode by means of the DSP 22 is 
conducted (step S810), and the procedure returns to the step S804. 
On one hand, when it has been judged that the normal performance mode had 
been set in the step S804, the DSP 22 is set to the normal performance 
mode, whereby the DSP 22 is adapted to be set so as to execute the DSP 
percussion signal processing routine shown in FIG. 12 (step S812). 
Thereafter, the normal performance processing routine by the CPU 24 shown 
in FIG. 19 is executed (step S814), then, processing for stopping the 
normal performance mode in the DSP 22 is conducted (step S816), and the 
procedure returns to the step S804. 
On the other hand, when it has been judged that the brushing performance 
mode had been set in the step S804, the DSP 22 is set to the brushing 
performance mode (step S818). Thereafter, the brushing performance 
processing routine by the CPU 24 is executed, then, processing for 
stopping the brushing performance mode in the DSP 22 is conducted (step 
S816), and the procedure returns to the step S804. It is to be noted that 
since the processing for brushing performance mode is not related to the 
subject matter of the present invention, the detailed description therefor 
will be omitted. 
In the following, the DSP percussion signal processing routine executed by 
the DSP 22 shown in FIG. 12 will be described, and the this processing is 
based on the following characteristic features. 
Namely, when detection signal of the head sensor 14 in the case when the 
head 12 composed of a net-like raw material is percussed is observed, 
there is such a characteristic that a first half-wave time changes 
dependent on a position of percussion point in a certain frequency band. 
More specifically, as shown in FIGS. 13(a) and 13(b), when the first 
half-wave time in the case where the center of the head 12 is percussed 
(position of percussion point A), the first half-wave time in the case 
where the outer circumference of the head 12 is percussed (position of 
percussion point C), and the first half-wave time in the case where the 
intermediate point defined between the center and the outer circumference 
of the head 12 is percussed (position of percussion point B) are 
represented by T.sub.A, T.sub.C, and T.sub.B. respectively, the 
relationship between them is expressed as follows. 
EQU T.sub.A &gt;T.sub.B &gt;T.sub.C. 
As described above, when the head 12 composed of a net-like raw material is 
percussed, with the movement of position of the percussion point from the 
center to the outer circumference, a first half-wave time shortens 
gradually. 
On one hand, when tuning of the head 12 is made high, i.e., tension of the 
head 12 is increased, the first half-wave times T.sub.A, T.sub.B, and 
T.sub.C shorten, respectively, while maintaining the relationship "T.sub.A 
&gt;T.sub.B &gt;T.sub.C ". On the other hand, when tuning of the head 12 is made 
low, i.e., tension of the head 12 is decreased, the first half-wave times 
T.sub.A, T.sub.B, and T.sub.C lengthen, respectively, while maintaining 
the relationship "T.sub.A &gt;T.sub.B &gt;T.sub.c ". 
FIG. 14 is a functional block diagram showing the constitution of a means 
for detecting the position of percussion point in a DSP 22. The outline of 
DSP percussion signal processing routine will be described by referring to 
FIG. 14. A detection signal detected by the head sensor 14 is subjected to 
analog-to-digital conversion by means of the analog-to-digital converter 
20, and the signal thus converted is input to a DC cut filter. The DC cut 
filter means a high pass filter for removing DC component. The DC 
component of the detection signal thus input to the DC cut filter is 
removed, and is input to a low pass filter (LP filter) removing 
unnecessary high pass component. Then, the detection signal from which 
unnecessary high pass component has been removed is input to a first 
half-wave detection circuit. The first half-wave detection circuit detects 
the leading edge of waveform of the detection signal thus input and the 
first zero cross, whereby the first half-wave is detected. A counter 
operates for counting during only a period wherein the first half-wave 
detection circuit detects first half-wave, and an arithmetic circuit 
calculates the position of percussion point from the count value of the 
counter. The position of percussion point thus calculated is input to the 
CPU 24 as percussion point positional information in head. 
The DSP percussion signal processing routine will be described herein in 
detail by referring to FIG. 12 wherein this DSP percussion signal 
processing routine is executed repeatedly in every sampling periods of the 
analog-to-digital converter 12. 
It is to be noted that since the above described functional block diagram 
shown in FIG. 14 indicates only the function for detecting percussion 
point positional information in head, a function for detecting percussion 
force information shown in FIG. 12 has been omitted. Furthermore, the 
functions for DC cut filter and LP filter shown in FIG. 14 are considered 
in FIG. 12 to be included in the processing for inputting sampling data S 
(step S902), so that the clear indication thereof is omitted for 
simplifying the flowchart. 
In the DSP percussion signal processing routine, the sampling data S is 
first input (step S902), and it is judged whether the leading edge has 
been detected or not (step S904). In the case where it was judged that the 
leading edge had been detected, a timer T is reset (step S906), then, a 
first count flag cf is turned ON (step S908), and a maximum value 
detection flag mf is turned ON (step S910). 
The detection of leading edge in the step S904 may be conducted 
specifically by either a manner wherein a difference between the present 
sampling data S and the preceding sampling data is determined, and if the 
difference is higher than the prescribed value which has been previously 
set, it is judged that there was a leading edge, or a well-known manner 
for detecting leading edge of input signal. 
Furthermore, the timer T is a means for measuring a prescribed period of 
time for detecting the maximum value of detection signal wherein the 
prescribed period of time is decided by a register time for storing the 
time which has been previously set. 
The first half-wave count flag cf is a flag representing whether counting 
processing for the first half-wave counter ct is to be made or not. When 
the first half-wave count flag cf has been turned ON, the counting 
processing for the first half-wave counter ct is made, while the counting 
processing for the first half-wave counter ct is not made in the case when 
the first half-wave count flag cf has been turned OFF. 
A maximum value detection flag mf is a flag representing whether detection 
processing for the maximum value of input data is to be made or not. When 
the maximum value detection flag mf has been turned ON, the detection 
processing for the maximum value is made, while the detection processing 
for the maximum value is not made, in the case when the maximum value 
detection flag mf has been turned OFF. 
In either the case where the processing in step S910 has been completed or 
the case where it has been judged that the leading edge had not been 
detected in the step S904, the procedure proceeds to step S912 wherein it 
is judged whether or not the first half-wave count flag has been turned 
ON. 
It is to be noted herein that the step S912, step S914, step S916, and step 
S918 relate to first half-wave count processing. In other words, the first 
half-wave count flag cf is turned ON from the step S912, and the first 
half-wave counter ct is incremental until the first half-wave is 
completed. 
More specifically, when it is judged that the first half-wave count flag 
has not been turned ON, i.e., the first half-wave count flag has been 
turned OFF, the procedure jumps to step S920 without accompanying the 
processing in the step S914, the step S916, and the step S918. 
On the other hand, when it is judged that the first half-wave count flag 
has been turned ON in the step S912, it is judged whether or not the first 
half-wave has been completed (step S914). Then, when it is judged that the 
first half-wave has not been completed, the first half-wave counter ct is 
made incremental (step S916), while when it is judged that the first half 
wave has been completed, the first half-wave count flag cf is turned ON 
(step S918), and the procedure proceeds to the step S920. 
The completion of the first half-wave in the step S914 corresponds to a 
point of time where the sampling data cross 0 (zero). Judgment whether the 
sampling data have crossed 0 (zero) or not may be made at the point of 
time when sign of the sampling data S turns, the contents of the judgment 
being such that the sampling data have crossed 0 (zero). 
In the step S920, it is judged whether the maximum value detection flag mf 
has been turned ON or not, and as a result, when it is judged that the 
maximum value detection flag mf has not been turned ON, i.e., it is judged 
that the maximum value detection flag mf has not been turned OFF, the DSP 
percussion signal processing routine is completed without taking a further 
step any more. 
On the other hand, when it is judged that the maximum value detection flag 
mf has been turned ON, it is further judged whether or not a timer T is 
larger than the register time (step S922). 
As a result, when the timer T is equal to or less than the register time, 
in other words, during a period where the maximum value detection flag mf 
has been turned ON and the timer T is equal to or less than the register 
time in the step S922, the maximum value detection processing is executed 
in step S924 and step S926. 
More specifically, the timer T is made incremental (step S924), the maximum 
value max is compared with the absolute value of the sample data S to 
rewrite the larger value into the maximum value max (step S916), and the 
DSP percussion signal processing routine is completed. 
Therefore, the maximum value max corresponds to the maximum value of a 
percussion signal within a prescribed time and decided by the register 
time. 
Furthermore, when the maximum value detection processing is completed as a 
result of such judgment that the timer T is larger than the register time 
in the step S922, the maximum value detection flag mf is turned OFF (step 
S928). 
Then, the first half-wave counter ct is converted into a percussion point 
positional information AP by employing table 1 which is a percussion point 
positional table for converting a first half-wave count value being a 
value of the first half-wave counter ct into the percussion point 
positional information AP (step S930). 
It is to be noted herein that the table 1 which is a percussion point 
positional table for converting a first half-wave count value being a 
value of the first half-wave counter ct into the percussion point 
positional information AP is selected in accordance with head type or 
tuning type. 
The head type is decided in response to a size of the head 12 so that TOM 
1, TOM 2, and SNARE are established in the present electronic percussion 
instrumental system. On one hand, the tuning type is decided in accordance 
with a tuning state of the head 12, i.e., in response to tension of the 
head 12 so that "loose", "medium" and "tight" are established in the 
present electronic percussion instrumental system. 
As described above, since three kinds of the head type and three kinds of 
the tuning type have been established in the present electronic percussion 
instrumental system, so that the table 1 of total nine kinds is provided. 
In FIG. 15, characteristics of the respective tuning types of loose, 
medium, and tight are indicated in the case where the head type is SNARE 
in respect of the table 1. A position of percussion point A (center), a 
position of percussion point B (intermediate), and a position of 
percussion point C (outer circumference) in the percussion point 
positional information AP correspond to the position of percussion point 
A, the position of percussion point B, and the position of percussion 
point C in FIG. 10, respectively. 
When completed the processing in the step 930, the procedure proceeds to 
step S932 wherein the percussion point positional information AP is 
converted into a percussion force correcting coefficient K by employing a 
table 2 which is a percussion force correcting table for converting the 
percussion positional information AP obtained in the step S930 into the 
percussion force correcting coefficient K (step S932). 
It is to be noted herein that the table 2 which is the percussion force 
correcting table for converting the percussion positional information AP 
is selected in response to head type and tuning type as in the case of the 
table 1. 
As described above, since three kinds of the head type, i.e., TOM 1, TOM 2, 
and SNARE as well as three kinds of the tuning type, i.e., "loose", 
"medium", and "tight" have been established in the present electronic 
percussion instrumental system, so that the table 2 of total nine kinds is 
provided. 
In FIG. 16, characteristics of the respective tuning types of loose, 
medium, and tight are indicated in the case where the head type is SNARE 
in respect of the table 2. A position of percussion point A (center), a 
position of percussion point B (intermediate), and a position of 
percussion point C (outer circumference) in the percussion point 
positional information AP correspond to the position of percussion point 
A, the position of percussion point B, and the position of percussion 
point C in FIG. 10, respectively. 
For instance, in the example shown in FIG. 16, when the tuning type is 
loose, "K=1" in the position of percussion point A (center), "K=4/3" in 
the position of percussion point B (intermediate), and "K=3" in the 
position of percussion point C (outer circumference). 
These head types and tuning types may be represented by numerical values, 
and further the table 1 as well as the table 2 are not limited to the nine 
kinds, respectively. 
When the processing in the step S932 is completed, the procedure proceeds 
to step S934 wherein compensation arithmetic processing in which the 
maximum value max is multiplied by the percussion force correcting 
coefficient K is conducted to calculate compensated percussion force 
information V. 
When completed the step S934, the procedure proceeds to step S936 wherein a 
sounding flag gf in the CPU 24 is turned ON, the percussion point 
positional information AP and the percussion force information V are set 
in the CPU 24, and the DSP percussion signal processing routine is 
completed. 
Then, the tuning processing routine executed by the CPU in the step S808 
will be described by referring to FIG. 17. 
In this tuning processing routine, it is judged whether or not there was an 
indication of change in a head type or a tuning type by operating a head 
type setting operation key (key for setting the head type) or a tuning 
type setting operation key (key for setting the tuning type) contained in 
the group of operation keys 30 (step S1402). At the time of turning on the 
power, a register head storing a head type and a register tuning storing a 
tunig type are also set in response to the initialized state of the head 
type setting operation key and the tunig type setting operation key in 
accordance with the processing of initialization in the step S802, 
respectively. 
After such judgement that change of head type or tuning type had been 
indicated by the operation of the head type setting key or the tuning type 
setting key of the group of operation keys 30 in the step S1402, it is 
judged whether or not the change of head type has been indicated (step 
S1404). 
When it was judged that the change of head type had been indicated, stored 
contents of the register head are changed in accordance with this 
indication of change (step S1406). 
In either the case where the processing in step S1406 has been completed, 
or the case where it was judged that the change of head type had not been 
indicated in the step S1404, it is judged whether or not the change of 
tuning type has been indicated (step S1048). 
When it was judged that the change of tuning type had been indicated, the 
stored contents of the register tuning is changed in accordance with this 
indication of change (step S1410). 
In either the case where the processing in step S1410 has been completed, 
or the case where it was judged that the change of tuning type had not 
been indicated in the step S1408, the table 1 or the table 2 is selected 
in accordance with the stored contents of the register head or the 
register tuning, and it is set to the DSP 22 (step S1412). 
As a result of conducting the procedure as described above, in either the 
case where the processing in step S1412 has been completed, or the case 
where it was judged that both the head type setting key or the tuning type 
setting key in the group of operation keys 30 had not been operated so 
that no change of the head type and the tuning type had not been 
indicated, the percussion point positional information AP sent out from 
the DSP 22 is displayed on the display unit 32 (step S1414). More 
specifically, the percussion point positional information AP set in the 
CPU in the DSP percussion signal processing routine is displayed on the 
display unit 32. 
In FIGS. 18(a), 18(b) and 18(c) are shown examples of manner of displaying 
the percussion point positional information AP displayed on the display 
unit 32 in the step S1414 wherein FIG. 18(a) shows a first displaying 
example, FIG. 18(b) shows a second displaying example, and FIG. 18(c) 
shows marks representing a variety of percussion point positional 
information AP being displayed in a display column for the percussion 
point positional information AP in FIG. 18(b), respectively. In FIGS. 
18(a) and 18(b), it is arranged in such that numbers which have been 
previously assigned to respective tuning types are displayed in the 
displaying column of tuning type. 
In FIG. 18(a), "CENTER" indicates the center position of the head 12, and 
"RIM" indicates a position of the rim 16. Furthermore, a black triangle is 
a mark indicating the percussion point positional information AP, while a 
white triangle is a tuning reference mark indicated in a position 
corresponding to the percussion point positional mark M indicated in the 
head 12 (see FIG. 20). 
Since a position between the center "CENTER" and the rim 16 "RIM" in the 
head 12 is decided by the percussion point positional information AP, the 
position thus decided is indicated by a black triangle. 
Furthermore, the tuning reference mark represented by a white triangle 
shows a position corresponding to the percussion point positional mark M 
indicated in the head 12 shown in FIG. 20 as described above. Namely, 
since the percussion point positional mark M shown in FIG. 20 is indicated 
at the position of intermediate point between the center "CENTER" and the 
rim 16 (RIM) in the head 12, the tuning reference mark represented by a 
white triangle is also indicated at the intermediate point between the 
"CENTER" and the "RIM" in FIG. 18(a). 
The manner for displaying the percussion point positional information AP on 
the display 32 is not limited to the examples shown in FIGS. 18(a), 18(b), 
and 18(c), but it may be indicated by either numerical values or a bar 
graph as in a level indication. 
When completed the processing in the step S1414, it is judged whether or 
not a termination key in the group of operation keys 30 has been operated 
(step S1416), so that if it was judged that the termination key in the 
group of operation keys 30 had not been operated, the procedure returns to 
the step S1402, and the processing is repeated. 
On the other hand, if it was judged that the termination key in the group 
of operation keys 30 had been operated in the step S1416, the procedure 
returns to the main routine. 
Then, a normal performance processing routine executed by the CPU 24 in the 
step S814 will be described by referring to FIG. 19. 
In the normal performance processing routine, it is first judged whether or 
not a level key (key for setting a volume of sounding musical tone), a 
tone color key (key for setting tone color of sounding musical tone), or a 
tuning key (key for setting a pitch of sounding musical tone) contained in 
the group of operation keys 30 has been changed. At the time when the 
power is turned on, a register level for storing level, a register tone 
for storing tone color, and a register pitch for storing pitch are set in 
response to the initialized state of the level key, the tone color setting 
key, and the tuning key, respectively, in accordance with the 
initialization processing in the step S802. 
In the step S1602, when it was judged that the level key, the tone color 
setting key, or the tuning key in the group of operation keys 30 had been 
changed, then, it is judged whether the level key has been changed or not 
(step S1604). 
In this case, if it was judged that the level key had been changed, the 
stored contents in the register level are changed in accordance with the 
former change (step S1606). 
In either the case where the processing in step S1606 has been completed, 
or the case where it was judged that the level key had not been changed in 
the step S1604, it is judged whether or not the tone color key has been 
changed (step S1608). 
In this case, when it was judged that the tone color key had been changed, 
stored contents of a register tone are changed in accordance with the 
former change, and a start address and an end address of waveform data 
corresponding to the stored contents of the register tone are set in the 
sound source IC 34 (step S1610). 
In either the case where the processing in step S1610 has been completed, 
or the case where it was judged that the tone color key had not been 
changed in the step S1608, it is judged whether or not the tuning 
operation key has been changed (step S1612). 
It is to be noted that the "tuning" in this step S1612 is different from 
the above described tuning of the head, and it means that a pitch is 
adjusted with respect to sounding musical tone (sound of a percussion 
instrument). 
In this case, when it was judged that the tuning key had been changed, 
stored contents of the register pitch are changed in accordance with the 
former change, and the pitch information corresponding to the stored 
contents of the register pitch are set to the sound source IC 34 (step 
S1614). 
When the processing in step S1614 has been completed as a result of 
conducting the procedure as described above, or it was judged that the 
tuning key had not been operated in the step S1612, or in the case where 
any of the level key, tone color setting key, or the tuning key in the 
group of operation keys 30 had not been changed, then, it is judged 
whether or not a sounding flag gf is turned ON (step S1616). 
Specifically, it is judged whether or not sounding has been instructed as a 
result of turning ON the sounding flag gf of the CPU 24 in the step S936 
of the DSP percussion signal processing routine. 
In this case, if it was judged that the sounding flag gf had been turned 
ON, the results of arithmetic computations of "level.times.V" are set to 
the sound source IC 34 as the level information (step S1618). More 
specifically, values stored in the register level which has been set by a 
level key are multiplied by percussion force information V to calculate a 
sounding level, and the results of this arithmetic computations are set to 
the sound source IC 34 as the level information. 
When completed the processing in the step S1618, the percussion point 
positional information AP is converted into a filter coefficient for 
controlling filter characteristics, and the converted information is set 
in the sound source IC 34 (step S1620). More specifically, when the 
converted information is set to the IC 34 after converting the percussion 
point positional information AP into the filter coefficient for 
controlling filter characteristics, tone colors corresponding to the 
positions of percussion point can be obtained. It is to be noted that the 
processing for obtaining tone colors corresponding to the positions of 
percussion point is not limited to that illustrated in the step S1620, but 
the processing in the step S1620 may be replaced by either a manner 
wherein waveforms to be read out are switched or a manner wherein a mixed 
ratio of a plurality of waveforms is changed. 
When the processing in the step S1620 is completed, the sounding flag gf is 
turned OFF (step S1622). In other words, as a result of conducting the 
procedure as described above, the sounding flag is turned OFF. 
In either the case where the processing in the step S1622 has been 
completed, or the case where it was judged that the sounding flag gf had 
been turned OFF in the step S1616, it is judged whether or not the 
termination key in the group of operation keys 30 has been operated (step 
S1624), so that if it was judged that the termination key of the group of 
operation keys 30 had not yet been operated, the procedure returns to the 
step S1602 to repeat the processing. 
On the other hand, when it was judged that the termination key in the group 
of operation keys 30 had been operated, the procedure returns to the main 
routine. 
The processing for sounding musical tones from the present electronic 
percussion instrumental system to the outside is carried out by 
controlling the sound source IC 34. 
In the following, a typical operational procedure for tuning operation of 
the head 12 will be described by referring to the flowchart shown in FIG. 
21. The flowchart of FIG. 21 illustrates the operational procedure of the 
tuning operation effected by a user after selecting the tuning mode by the 
user. 
Namely, when the user selects the tuning mode, then he or she sets first a 
desired head type by operating a head type setting key in the group of 
operation keys 30 (step S1802), and thereafter, he or she sets a desired 
tuning type by the operation of a tuning type setting key of the group of 
operation keys 30 (step S1804). 
In accordance with the operations in the steps S1802 and S1804, the 
processing specified in the respective steps S1402, S1404, S1406, S1408, 
S1410, and S1412 contained in the tuning processing routine executed by 
the CPU shown in FIG. 17 is conducted. 
Then, in this tuning operation, a mark M at the position of percussion 
point in the head 12 which is placed at a position close to the engaging 
pin 54 in operation is percussed (step S1806). It is to be noted that the 
procedure on and after the step S1806 becomes actual tuning operations. 
In the step S1806, when the mark M at the position of percussion point of 
the head 12 is percussed, the percussion point positional information AP 
sent from the DSP 22 as a result of execution of percussion signal 
processing routine shown in FIG. 12 is displayed on the display unit 32 in 
the step S1414 contained in the tuning processing routine executed by the 
CPU shown in FIG. 17. 
In this case, it is confirmed that a black triangle indicating the 
percussion point positional information AP due to the result of the 
percussion in the step S1806 has been displayed at which position by 
visual observation of the display unit 32 (step S1808). 
Then, it is judged whether or not there is a misregistration between the 
position of the black triangle indicating the percussion point positional 
information AP and a white triangle indicating the tuning reference mark 
(step S1810). 
In this case, when it is judged that there is a misregistration between the 
position of the black triangle indicating the percussion point positional 
information AP and the white triangle indicating the tuning reference 
mark, the engaging pin 54 is adjusted so as to cancel the aforesaid 
misregistration, thereby carrying out tuning for adjusting tension of the 
head 12 (step S1812). 
Thus, after completing the operation in the step S1812, the procedure 
returns to the step S1806 and the operation is repeated. 
On the other hand, if it was judged that there was no misregistration 
between the position of the black triangle indicating the percussion point 
positional information AP and the white triangle indicating the tuning 
reference mark, then it is judged whether the tuning operation has been 
completed or not (step S1814). In this case, the judgment whether or not 
the tuning operation has been completed is specifically a judgment whether 
or not tuning operations of all the engaging pins 54 have been completed. 
In this case, when it was judged that the tuning operations had not been 
completed, the procedure returns to the step S1806 to perform tuning 
operations with respect to the engaging pins 54 to which have not yet been 
subjected the tuning operations. 
On the contrary, when it was judged that the tuning operations had been 
completed, the procedure of the tuning operation is finished. 
It is to be noted that the above described manner of practice may be 
modified as follows. 
(1) As shown in FIG. 22, the head 12 is fixed to either side of the opening 
of the barrel section 50, while the head of an acoustic drum (cannot be 
found in FIG. 22) may be fixed to the other side of the opening of the 
barrel section. In this case, when the head 12 is percussed, the head of 
acoustic drum positioned on the opposite side resonates to sound at an 
appropriate volume. Accordingly, when compared with the case where only 
the head 12 is fixed to the barrel section 50, a player can perform the 
percussion instrument with much more close feeling to that of acoustic 
drum. 
(2) As shown in FIG. 23, to the outer circumference of the head 12 composed 
of the first net 56 and the second net 58 may be bonded an annular film 
112. In this case, since a ratio of opening in the first net 56 and the 
second net 58 of the head 12 becomes low in comparison with that of the 
above described manner of practice, the percussion sound becomes larger 
than that of the above described manner of practice. For this reason, a 
player can perform the resulting percussion instrument with much more 
close feeling to that of acoustic drum. Furthermore, when an area of the 
film 112 to be bonded to the first net 56 and the second net 58 in the 
head 12 is allowed to vary, the volume in percussion can be controlled. 
Moreover, stitches may be filled with an adhesive to bond the first net 56 
to the second net 58 in place of bonding of the film 112. 
(3) The net-like raw material is not limited to a two-ply plane weave net, 
but one-ply or three- or more ply net may also be used. Furthermore, a 
weaving manner of net is not limited merely to plane weave. In the case 
where a net-like raw material is composed of a single net, it is preferred 
to use a triaxially woven net which balances tension not only in the 
crossed direction of woven fibers, but also in an oblique direction. 
(4) A shape of the cushioning member 80 in the head sensor 14 is not 
limited to the frustoconical shape, but a truncated pyramid shape may be 
adopted. 
(5) A constitution of the sound source is not limited to the above 
described wave-form read-out system, but sound sources of a variety of 
systems may be employed. Furthermore, a PCM sound source sounding PCM 
sampling sounds is not used, but a resonator composed of oscillator and 
the like may be used, otherwise audio signals input from the outside may 
also be employed. 
(6) While the percussion point positional information AP has been displayed 
on the display 32 in the above described manner of practice, instead of 
the display, it may be adapted to sound such sound signal having a pitch 
corresponding to the percussion point positional information AP. 
(7) Although the percussion point positional mark M indicated on the top of 
the head 12 has been configured in the circular shape as shown in FIG. 20 
in the above described manner of practice, a shape of the percussion point 
positional mark M is not limited to the circular shape as shown in FIG. 
20, but, for example, the percussion point positional mark M may be 
indicated by points of a prescribed number as shown in FIG. 24(a). 
Moreover, a region of the head 12 is classified by coloring as shown in 
FIG. 24(b) (It is to be noted in FIG. 24(b) that a shaded portion of the 
region of the head 12 is represented by a different color from that of the 
other (no shaded) portion), and the boundary portion classified by 
coloring may be used as the percussion point positional mark M. 
(8) While it has been arranged in such that the tuning reference mark 
represented by white triangle shown in FIG. 18(a) is indicated in response 
to the percussion point positional mark M of the head 12 in the above 
described manner of practice, the invention is not limited thereto, but, 
for instance, it may be arranged in such that information for indicated 
position by a white triangle may be stored as the tuning reference data 
together with the table 1 and the table 2 which are selected in accordance 
with the head type or the tuning type set in the tuning processing routine 
executed by the CPU shown in FIG. 17. 
(9) Although the black triangle indicating the percussion point positional 
information AP and the white triangle indicating the tuning reference mark 
corresponding to the percussion point positional mark M of the head have 
been displayed on the display unit 32 in the above described manner of 
practice as shown in FIG. 18(a), a displaying manner on the display unit 
32 is not limited thereto, but, for example, a deviation between the above 
described tuning reference data and the detected percussion point 
positional information AP may be displayed as shown in FIG. 25. 
Specifically, the manner may be carried out in such a way that tuning 
reference data are read out in case of the processing for displaying the 
percussion point positional information AP in the step S1414 of the tuning 
processing routine executed by the CPU shown in FIG. 17, a deviation 
between the tuning reference data and the percussion point positional 
information AP is calculated, and the deviation represented by the 
calculated result is displayed on the display unit 32. If it has been 
adapted to display "0" on the display unit 32 in case of no deviation, it 
means that tuning is matched in the case when indication "0" is displayed 
on the display unit 32. 
(10) As a displaying manner in the display unit 32, there are a manner 
wherein it may notify that the tuning is matched in the case when a 
difference between the tuning difference data and the percussion point 
positional information AP reaches a prescribed value or lower, and a 
manner wherein a difference between the tuning reference data and the 
percussion point positional information AP may be displayed in accordance 
with cent indication as utilized in a tuning device for stringed 
instruments such as guitar and the like in addition to the manners 
described above. 
Since the present invention has been constituted as described above, it 
provides such an excellent advantage that a percussion detecting 
apparatus, which is excellent in percussion feeling, and the percussion 
sounds of which are very small, in electronic percussion instrumental 
system can be realized. 
Furthermore, since the indication corresponding to a percussion position of 
the head has been made in the present invention, such an excellent 
advantage that correct tuning can easily be carried out in case of tuning 
the head is obtained. 
Moreover, since a variation in tension of the head due to tuning of the 
head has been compensated in the present invention, such an excellent 
advantage that correct percussion position can be detected is obtained. 
Still further, since a tuning operation can be conducted by a user in 
accordance with such a manner that a place marked with a percussion point 
positional mark is percussed by the user, and the result detected at that 
time by the detecting means for position of percussion point is confirmed 
while watching the display means in the present invention, such an 
excellent advantage that tuning operation can simply be carried out 
without relying upon user's sense is obtained. 
It will be appreciated by those of ordinary skill in the art that the 
present invention can be embodied in other specific forms without 
departing from the spirit or essential characteristics thereof. 
The presently disclosed embodiments are therefore considered in all 
respects to be illustrative and not restrictive. The scope of the 
invention is indicated by the appended claims rather than the foregoing 
description, and all changes that come within the meaning and range of 
equivalents thereof are intended to be embraced therein. 
The entire disclosure of Japanese Patent Applications No. 8-193986 filed on 
Jul. 4, 1996, No. 9-15846 filed on Jan. 13, 1997 and No. 9-15847 filed on 
Jan. 13, 1997 including specification, claims, drawings and summary are 
incorporated herein by reference in their entirety.