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JP2012208487

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DESCRIPTION JP2012208487
Abstract: PROBLEM TO BE SOLVED: To provide a tuning method and apparatus for a percussive
percussion instrument with a certain pitch that enables accurate tuning under an environment
where there is a sound other than the tuning target sound. SOLUTION: A sheet-like piezoelectric
sensor having flexibility is disposed on a membrane of a membrane sounding percussion
instrument, and the vibration of the membrane is converted into an electric signal, and the name
of the note is determined by an electronic circuit processing the electric signal. A method and
apparatus for tuning a membrane sound percussion instrument having a pitch of about.
Preferably, the piezoelectric sensor is a cantilever type piezoelectric film sensor. [Selected figure]
Figure 8
Method and apparatus for tuning a membrane sounding percussion instrument
[0001]
The present invention relates to a method and apparatus for tuning a loud-sounding percussion
instrument, and more particularly to a method and apparatus for tuning timpani (also referred to
as a kettle drum).
[0002]
As a tuner for easily performing tuning (tuning) of a percussion instrument, the sound collected
from the microphone is converted into an electric signal, amplified to an electric signal of a
desired level by an amplifier, and the sound collected by the microphone from the output signal
of the amplifier There is a tuning device which extracts the basic period of and tunes in
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accordance with a preset reference tone.
In Patent Document 1, a timpani's pitch adjustment device detects the hitting sound of the head
with an external microphone, measures the frequency with a tuning meter to determine the pitch,
and automatically sets the degree of tension of the head based on the judgment signal. It is
disclosed.
[0003]
As a tuner which performs tuning (tuning) of a wind instrument easily, the thing of the clip type
using a contact microphone and a piezo microphone is sold. A cordless type is also proposed. For
example, Patent Document 2 discloses a clip for mounting on a musical instrument, a vibration
sensor provided on the clip, and a clip and a connecting portion to be connected to each other,
Disclosed is a tuning device having an electronic circuit that determines a voice state of the
musical instrument by processing a signal obtained from the vibration sensor, and a display unit
that displays the determination result of the electronic circuit. There is.
[0004]
Patent No. 4109302 gazette JP, 2003-255932, A
[0005]
In the configuration in which the sound is collected by the microphone as in Patent Document 1,
all the surrounding sounds are detected, so in an environment where there is a sound other than
the tuning target sound, such as in the case of concerts by many people. There was a problem
that accurate tuning was difficult.
In particular, it was virtually impossible to accurately change the pitch using a tuning gauge
while playing.
[0006]
In addition, the contact microphone / piezo microphone and the tuner for wind instruments as
shown in Patent Document 2 can not be used for tuning a percussive percussion instrument (a
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percussion instrument with a leather or a plastic film).
[0007]
An object of the present invention is to provide a method and an apparatus for tuning a pitched
percussion instrument which can solve the above-mentioned problems.
[0008]
When tuning a percussive percussion instrument with a pitch of about with the conventional
contact microphone and piezo microphone, it was not possible to accurately measure the
frequency of the percussion sound.
The inventors considered that this is caused by the use of a ceramic piezoelectric (piezo) sensor
in the conventional contact microphone / piezo microphone.
That is, since the ceramic-based piezoelectric sensor is made of a hard material as shown in FIG.
1 and is not a flexible structure as shown in FIG. 1, the inventor not only inhibits head vibration
but also FIG. It was found that the vibration of Timpani's head as shown could not be converted
into an electrical signal. Then, the inventor considered the frequency of striking sound accurately
with the sheet-like piezoelectric sensor having flexibility, and made the present invention after
earnestly examining.
[0009]
That is, according to the first aspect of the present invention, a sheet-like piezoelectric sensor
having flexibility is disposed on a membrane of a membrane sounding musical instrument, the
vibration of the membrane is converted into an electrical signal, and the electronic name
processing the electrical signal determines the name of the note And a tuning method of a
pitched percussive instrument characterized in that: According to a second invention, in the first
invention, the piezoelectric sensor is a cantilever type piezoelectric film sensor. A third invention
is characterized in that, in the first invention, the piezoelectric sensor includes a U-shaped
piezoelectric film sensor whose lower surface is disposed on a membrane of a percussion
instrument. A fourth invention is characterized in that, in any one of the eleventh to the third
inventions, the piezoelectric sensor includes a film of polyvinyl fluoride (PVDF). According to a
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fifth invention, in any one of the first to fourth inventions, the percussion instrument is a timpani.
[0010]
A sixth aspect of the present invention is a flexible sheet-like piezoelectric sensor disposed on a
membrane of a membrane sounding percussion instrument, which converts vibration of the
membrane into an electrical signal, and transmitting the electrical signal obtained from the
piezoelectric sensor to an external tuner And an output circuit for performing tuning. A seventh
invention is a sheet-like piezoelectric sensor having flexibility, which is disposed on a membrane
of a membrane sounding percussion instrument and converts the vibration of the membrane into
an electrical signal, and processes the electrical signal obtained from the piezoelectric sensor to
produce sound. It is a tuning device for a membrane sound percussion instrument having a range
of sounds, comprising: a processing unit for determining a name; and a display unit for
displaying a determination result by the processing unit. An eighth invention is characterized in
that, in the sixth or seventh invention, the piezoelectric sensor is a cantilever type piezoelectric
film sensor. A ninth invention is characterized in that, in the sixth or seventh invention, the
piezoelectric sensor includes a U-shaped piezoelectric film sensor whose lower surface is
disposed on a film of a percussion instrument. A tenth invention is characterized in that, in any
one of the sixth to ninth inventions, the piezoelectric sensor includes a polyvinyl fluoride (PVDF)
film. An eleventh invention is characterized in that, in any one of the sixth to tenth inventions, the
percussion instrument is a timpani.
[0011]
According to the present invention, it is possible to simply and accurately perform tuning of a
membrane sound percussion instrument having a pitch with a piezoelectric sensor.
[0012]
It is a side view which shows the structure of the conventional ceramic type piezoelectric sensor.
It is a top view which shows the vibration image of the head of Timpani. 5 is a photograph
showing a measurement mode using the tuning device according to Example 1. FIG. 7 is a graph
of voltage change when measured by the tuning device according to the first embodiment. It is a
frequency spectrum of FIG. 5 is a graph of voltage change when measured by the tuning device
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according to the second embodiment. It is a frequency spectrum of FIG. FIG. 14A is a top view
and a side view showing a structure of a piezoelectric film sensor according to a third
embodiment. It is a figure explaining the structure of a piezoelectric film sensor, and the method
of a change of resonant frequency. 15 is a graph of voltage change when measured by the
piezoelectric film sensor according to Example 3. It is a frequency spectrum of FIG. FIG. 16 is a
graph of voltage change when measured by the piezoelectric film sensor according to Example 4.
FIG. It is a frequency spectrum of FIG. FIG. 16 is a side view showing the structure of a
piezoelectric film sensor according to a fourth embodiment. FIG. 16 is a frequency spectrum as
measured by the piezoelectric film sensor according to Example 4. FIG. It is a frequency spectrum
at the time of measuring in each position of i-iv of FIG.
[0013]
According to the present invention, a sheet-like piezoelectric sensor having flexibility is disposed
on a membrane of a membrane sounding percussion instrument to convert the vibration of the
membrane into an electrical signal, and the pitch name is determined by an electronic circuit
processing the electrical signal. The present invention relates to a method and apparatus for
tuning a percussion instrument.
[0014]
Since the piezoelectric sensor needs to follow the vibration of the head (film), a flexible sheet-like
piezoelectric sensor, preferably one in the form of an elastic film, is used.
Piezoelectric films include piezoelectric ceramics or piezoelectric ceramic thin films made of
PVDF (polyvinylidene fluoride film), barium titanate, lead zirconate titanate (PZT), etc. PVDF is
preferred as a preferred material. PVDF has also a feature that the response band is very wide
and it is difficult to have an inherent resonant frequency. Although some piezoelectric elements
are made of an inflexible material such as ceramic, they are not used in the present invention
because they can not follow the vibration of the head (film) as described above.
[0015]
An adhesive layer is formed on the lower surface side of the piezoelectric sensor as needed, or
can be attached to the head of a timpani using a double-sided adhesive sheet, an adhesive tape or
the like. At this time, the piezoelectric sensor may be in pressure contact with the head by a
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member pressed from the upper surface side of the piezoelectric sensor at a surface or a plurality
of points having a predetermined area or more. Another form is disclosed using a cantilever type
piezoelectric film sensor. The piezoelectric film sensor includes a substrate disposed on a
membrane of a membrane percussion instrument, a pin provided perpendicular to the substrate,
a plate-like detection element attached to the pin so as to be substantially horizontal to the
substrate, and a detection element. It comprises a sheet-like piezoelectric sensor (piezoelectric
film) disposed, and a weight provided so as to be attached to and detached from the detection
element. The number of piezoelectric sensors may be single or plural.
[0016]
It is preferable to take measures against noise by shielding the piezoelectric sensor with a
conductive cloth tape or the like. The conductive cloth tape may be a general tape used for
shielding electromagnetic waves and static electricity of electronic devices, and shielding of
signal cables and connectors, and since the adhesive surface is also conductive and has
continuity even when bonded, The shield effect can be obtained.
[0017]
The signal from the piezoelectric sensor is amplified to an electrical signal of a desired level by
an amplifier circuit as necessary, and is input to a commercially available tuning meter (tuner).
The tuning meter analyzes and extracts the basic period of the input sound, compares the
extracted basic period and the period of the basic sound, determines the pitch of the input sound,
and detects the pitch error in the determined pitch Be done. The pitch and pitch error of the
input sound are displayed on the display of the tuning meter. Thus, the piezoelectric sensor
according to the present invention makes it possible to perform tuning using a commercially
available tuning meter. The pitch error in the processing unit for discriminating the pitch name
based on the discrimination reference information stored in the storage unit and the electric
signal from the sheet-like piezoelectric sensor (or amplification circuit) having flexibility
described above and the display unit such as liquid crystal display The tuning apparatus provided
with the display part displayed on a scale etc. is also contained in the scope of the present
invention.
[0018]
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Timpani is known as a membranous percussion instrument with a pitch. Timpani can change the
pitch by adjusting the tension of the head, and can accurately separate out the sound of the
Doremi. One timpani has, for example, a range from de to la (flat), and usually four to five
timpani are used side by side when playing.
[0019]
Timpani plays by putting a head (membrane) on a round pot-shaped kettle made of copper, FRP,
aluminum, etc., and striking it with a bee (mallet). You can change the pitch by adjusting the
tension of the head, you can accurately split out the sound of Doremi. The tension of the head
can be adjusted by hand-tightening the tuning bolt with one hand, handle-type by turning all the
tuning bolts at the same time, and adjusting the head tension by stepping on the pedal. There is a
pedal type to change. The tuning bolt is connected to a radial tension rod provided from a
bracket at the center of the head, and the tension rod adjusts the tension of the head.
[0020]
Timpani makes a sound by hitting the area near the edge of the head, not the center of the head.
The entire head is corrugated with a straight line passing through the center from side to side,
and the edge hits the antinode portion of the vibration. FIG. 2 is a top view showing a vibration
image of the head when hitting near the edge. In FIG. 2, the filled part is a bulged part and the
unpainted part is a dented part, and the states of (A) and (B) are repeated, and the whole head
makes a sound while waving. Air trapped in a round kettle is said to provide membrane
oscillations of the correct integer multiple of discipline.
[0021]
Hereinafter, the present invention will be described in detail by way of examples, but the present
invention is not limited to the examples.
[0022]
Example 1 relates to a timpani tuning device using a piezoelectric film sensor.
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In Example 1, a piezoelectric film was attached approximately at the center of the timpani head
that was pre-tuned, and experiments were conducted to determine whether the note name can be
correctly determined (see FIG. 3). The tuning device of Example 1 amplifies the signal from the
piezoelectric film with the first amplifier (a charge amplifier manufactured by itself) and the
second amplifier (manufactured by Shikoku Kagaku Kogyo Co., Ltd.), and the data logger (ZRMDR10 manufactured by OMRON Corporation). And its dedicated PC software is configured to
observe. The amplifier is configured in two stages, the first stage (charge amplifier) is an
amplifier that converts the charge induced in the piezoelectric film into a voltage, and the second
stage (voltage adjustment amplifier) is the measuring equipment on the output side. It is an
amplifier that performs voltage conversion according to the input voltage. Since changing the
amplification factor in the first stage (charge amplifier) may change the input resistance etc., the
charge induced in the piezoelectric film is converted to a voltage without change in input
resistance with the first stage (charge amplifier) fixed. It converts, and when output voltage is
small, it is made to amplify by 2nd stage (voltage adjustment amplifier). The tuning device of the
first embodiment amplifies the signal from the piezoelectric film with a first amplifier (charge
amplifier) and a second amplifier (voltage adjustment amplifier) manufactured by Shikoku
Kagaku Kogyo Co., Ltd. -MDR 10) and its dedicated PC software are configured to observe.
[0023]
There is a possibility that noise may be observed depending on the measurement conditions
around the power supply frequency of 60 Hz (50 Hz for East Japan) and 180 Hz (150 Hz for East
Japan), and therefore a notch filter is inserted.
[0024]
In Example 1, a piezoelectric film (FDT series) manufactured by Tokyo Sensor Co., Ltd. was used.
In this product, this piezoelectric film is constructed by extending a silver ink screen printed
electrode as a flexible circuit integrated with the sensor unit and attaching a connector. The
specifications of the piezoelectric film used in Example 1 are shown below.
[0025]
Model No .: FDT1-052 K Sheet size: 16 mm x 235 mm Electrode size: 12 mm x 30 mm Overall
thickness: 85 μm Film thickness: 52 μm Capacitance: 0.74 nF
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[0026]
FIG. 4 is obtained by amplifying the signal from the piezoelectric film when the sound of A (220
Hz) is beaten by a first amplifier by a factor of 1000 and amplifying it by a second amplifier by a
factor of 11.3 It is a graph of a voltage change.
FIG. 5 is a frequency spectrum obtained by Fourier-transforming FIG. 4 and a peak could be
observed at 222.17 Hz
[0027]
Subsequently, an interconnection experiment with a commercially available tuner (TDM-70
manufactured by Yamaha Corporation) was performed. When the signal of the piezoelectric film
amplified by 1000 times with the first amplifier is input to the tuner whose tuning frequency is
set to 440 Hz by tapping the timpani weakened in advance, the needle of the cent scale shows
the center 0 and the sound The green lamp turned on to indicate that the
[0028]
From the above results, it could be confirmed that the tuning device of Example 1 can correctly
discriminate the sound of A (220 Hz).
[0029]
Using the same tuning device as in Example 1, a piezoelectric film was attached approximately to
the center of the Timpani's head, and experiments were conducted to determine whether or not
the pitch name could be correctly determined.
In the second embodiment, the pedal of the timpani is moved from the first embodiment to a
non-tuned situation. Although the second embodiment strikes with the same strength as the first
embodiment, it is not completely the same because it is manually operated.
[0030]
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FIG. 6 is obtained by amplifying the signal from the piezoelectric film when the sound of A (220
Hz) is struck three times by the first amplifier and amplifying it by 11.3 times by the second
amplifier. It is a graph of a voltage change. FIG. 7 is a frequency spectrum obtained by Fouriertransforming FIG. From FIG. 7, a peak could be observed at 221.56 Hz.
[0031]
Example 3 relates to a timpani tuning device using a cantilever type piezoelectric film sensor. In
the third embodiment, an output of about 10 times that in the first embodiment is obtained, so
that a simple configuration without using an amplifier can be achieved. That is, according to the
piezoelectric film sensor of the third embodiment, tuning can be performed by directly
connecting the piezoelectric film sensor to a commercially available tuner (TDM-70
manufactured by Yamaha Corporation).
[0032]
FIG. 8 is a top view and a side view of a cantilever type piezoelectric film sensor according to a
third embodiment. In Example 1, MiniSense 100 manufactured by Tokyo Sensor Co., Ltd. was
used. This product is a low-cost cantilever-type vibration sensor with a weight 13 that exhibits
high sensitivity at low frequencies. The pins 12 are designed to be easily attached and can be
soldered to a printed circuit board (PCB) or the like. The active sensor part is shielded and is less
susceptible to RFI / EMI noise. The piezoelectric film 11 is PVDF, and the weight of the weight to
be detected can be changed so that different frequency responses and sensitivities can be
selected. When a weight of inertial force is applied to the end of a horizontally mounted beam,
acceleration in the vertical plane causes the beam to bend, causing the beam to distort causing
the piezoelectric response and sensing as charge or voltage output from the sensor's electrodes
Be done. Since the MiniSense 100 is originally a low pass filter, if it can be matched to the
timpani generated frequency, almost no electronic filter is necessary. In addition, since there is
also a resonant frequency, it is conceivable to use a highly sensitive resonant portion.
[0033]
The piezoelectric film sensor is preferably installed near the center of the timpani. This is
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because the vibration is limited if the sensor is attached to the opposite side to which it was
struck. Although the middle of the timpani is a portion that hardly vibrates theoretically, it was
confirmed from the measurement results described later that the sensor actually vibrated to a
sufficient degree. The structure of the piezoelectric film sensor and the change of the resonance
frequency have the correlation shown in FIG. That is, the correlations with the weight of the
weight, the distance between the weight and the pin, and the hardness of the piezoelectric film
are recognized above and below the resonance frequency.
[0034]
The sound of A (220 Hz) was measured with a piezoelectric film sensor using the same data
logger as in Example 1 and its dedicated PC software. FIG. 10 is a graph showing a voltage
change when the sound of A (220 Hz) is measured by changing the weight of the weight. In FIG.
10A, two weights (about 0.24 g) are disposed at the tip of the piezoelectric film, and in FIG. 10B,
one weight (about 0.12 g) is disposed at the tip of the piezoelectric film. In (C), measurement was
performed without weight. FIG. 11 is a graph of a frequency spectrum obtained by Fouriertransforming FIG. In FIGS. 11A and 11B, a large peak is observed around 223 Hz, which is close
to the sound of A. Although a peak is also observed around 164 Hz, it is presumed that this is
due to the impact when struck. In FIG. 11C, in addition to around 224 Hz, smaller peaks can be
observed at 166 Hz and 336 Hz. Here, a 336 Hz peak has newly appeared, but since this is the
third harmonic of 112 Hz one octave below the fundamental frequency, it is not strange that it
can be observed. From FIGS. 10 and 11, it was confirmed that high output can be obtained
without using an amplifier according to the cantilever type piezoelectric film sensor.
[0035]
Under the same conditions as in Example 3, the sound of G (97 Hz) was measured by changing
the weight of the weight. FIG. 12 is a graph showing a voltage change when the G sound (97 Hz)
is measured while changing the weight of the weight. In FIG. 12 (A), two weights (about 0.24 g)
are disposed at the tip of the piezoelectric film, and in FIG. 12 (B), one weight (about 0.12 g) is
disposed at the tip of the piezoelectric film. In (C), measurement was performed without weight.
FIG. 11 is a graph of a frequency spectrum obtained by subjecting FIG. 12 to Fourier transform.
In FIGS. 13A and 13B, a large peak is observed around 97 Hz near the sound of G. Here, even
after Fourier transform of the afterglow, there was no change in the ratio. In FIG. 13C, no peak
could be observed around 97 Hz. This is because without the weight, only high frequency
components can be picked up. From FIG. 12 and FIG. 13, it was confirmed that there is a
correlation between the weight of the weight and the change of the resonance frequency. In
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addition, since the frequency of G sound is low, it was confirmed that the measurement was
difficult without the weight with the distance between the weight of this product and the pin and
the hardness of the piezoelectric film. In addition, the same tendency was observed also in the
sound of A (110 Hz) one octave lower than Example 3, and it was confirmed that measurement
was difficult without weight.
[0036]
Example 5 relates to a timpani tuning device having a curved piezoelectric film sensor. The
piezoelectric sensor 10 according to the present embodiment includes a piezoelectric film 11
curved in a U-shape, an arm 14 to which the upper surface of the piezoelectric film 11 is fixed, a
support 15 made of a rod-like body connected to the arm 14, and a support And a fixed portion
16 provided below the lower portion 15. The piezoelectric sensor 10 is used by being connected
to the first and second amplifiers of the first embodiment by signal lines (not shown) extending
from the fixed portion 16. The piezoelectric film 11 has an upper surface, a lower surface, and a
curved portion, and is used in a state in which the lower surface is in contact with the timpani
head 21 when the upper surface and the lower surface are substantially horizontal. Here, the
lengths of the upper surface and the lower surface do not have to be the same length, and it is
sufficient if a certain area of the lower surface abuts on the head 21.
[0037]
As shown in FIG. 14, the piezoelectric sensor 10 can be detachably fixed to a Timpani tuning bolt,
a frame, or the like by the fixing portion 16. The fixing portion 16 in this embodiment is a device
for gripping the tympani tuning bolt 22 with a spring-loaded jaw. The piezoelectric sensor 10 is
attached at a position where the lower surface of the piezoelectric film 11 abuts on the timpani
head 21. Here, the support portion 15 is preferably configured to be able to adjust the length of
the rod-like body by a screw or the like. The arm 14 is configured to have a length such that the
piezoelectric film 11 is located at a predetermined distance from the outer periphery (fastening
frame) of the head 21. FIG. 15 is a graph of a frequency spectrum obtained by Fouriertransforming the output of the piezoelectric sensor 10 of the present embodiment. Fig. 15 (A)
shows the result of measuring the sound of G and Fig. 15 (B) shows the result of E. In the former,
a peak is observed at 98 Hz, and in the latter, a peak is observed at 82 Hz. Was confirmed to be
obtained.
[0038]
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The measurable frequency differs depending on the positional relationship between the
piezoelectric film 11 and the head 21. That is, by changing the distance from the outer periphery
of the head 21 of the piezoelectric film 11, the measurable frequencies are different. Therefore, it
is preferable that the length of the arm 14 be adjusted by a screw or the like in the range of the
radius of the timpani. Further, since the optimum length of the arm 14 differs for each timpani,
the piezoelectric sensor 10 having the arm 14 of a length corresponding to a specific model
number of each manufacturer may be provided.
[0039]
FIG. 16 is a graph of a frequency spectrum obtained by subjecting the output at the time of
measuring the sound of G at each position of i to iv in FIG. 14 to Fourier transform. As can be
seen from the figure, it can be seen that the appearance of peaks other than the frequency (98
Hz) to be measured differs depending on the measurement position (the distance from the
clamp). That is, it is possible to confirm that the frequency to be measured can be measured with
low noise by selecting the optimal measurement position (the position iii in the same figure).
[0040]
DESCRIPTION OF SYMBOLS 1 upper electrode 2 piezoelectric material 3 lower electrode 4
wiring + 5 wiring-10 piezoelectric sensor 11 piezoelectric film 12 pin 13 weight 14 arm 15
support part 16 fixing part 20 tympani 21 head 22 tuning bolt 23 frame 24 kettle
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