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BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a tuning apparatus to be used for tuning musical
instruments, particularly to a tuning apparatus which has a mounting
member so as to be mounted on the musical instruments to be tuned.
2. Description of the Prior Art
As a tuning apparatus of the prior art Japanese Patent Laid-Open No.
164092/1987 to Seiko Instruments Inc., relates to a tuning apparatus which
has a microphone for detecting a sound of a musical instruments to be
tuned, as shown in FIG. 13. The sound produced by the musical instruments
is inputted into a pickup, e.g., microphone, and converted into an
electrical signal. The electrical signal is filtered by a filter 24 which
has a band-pass width for passing each octave frequency. The signal
provided by the filter 24 is processed by a pitch calculation circuit 3
through a waveform shaping circuit 2. The pitch calculation circuit 3
calculates an octave, a note and pitch deviation of the signal on the
basis of a reference signal outputted from a reference signal generation
circuit 4. The calculated results are displayed by a display 6 composed of
an LED, liquid crystal display or the like. However, the conventional
tuning apparatus picks up noise around the instrument to be tuned when the
sound of the instrument is inputted to the microphone, and tuning is very
difficult. In the case of inputting an electric signal outputted from a
musical instrument to be tuned into the tuning apparatus through a cord
coupling the musical instrument with the tuning apparatus, the cord is
impedimental for a player and a noise induced on the cord makes tuning
difficult.
In order to solve the above problems, another tuning apparatus having a
built-in electromagnetic pickup such as that shown in FIG. 14 is also
known. Although the above described problem is solved because the input
signal is neither a sound nor an electric signal but an electromagnetic
signal, the instruments being tuned are restricted to instruments using
metal chords. In addition, an electromagnetic pickup 26 must be situated
right above a chord 27 so as to sense the magnetic field and, as a result,
tuning must be conducted while holding a tuning device 25 with one hand,
thereby making tuning very troublesome.
Furthermore, in some musical instruments, a harmonic component such as a
double wave and a triple wave produces a larger sound than a fundamental
wave component. It is well known that when an amplitude of a double wave
or a triple wave is larger than that of the fundamental wave, they are apt
to be mistaken for the notes one octave higher and five degrees higher,
respectively. To prevent this, it is necessary to insert the filter 2 as
shown in FIG. 13, which makes the amplitude of the fundamental wave
component larger than that of the harmonic component. However, since the
tuning apparatus must have a plurality of filters for each octave, the
scale of the circuit is enlarged. It is therefore impossible to obtain a
small and inexpensive tuning appratus which is capable of exact detection
of an octave.
SUMMARY OF THE INVENTION
An object and advantage of the present invention is to provide a tuning
apparatus which is able to accurately tune a musical instrument without
fear of picking up the noise around the musical instrument.
Another object of the present invention is to provide a tuning apparatus in
which a piezoelectric element is incorporated thereinto and picks up
vibration from the musical instrument through a tuner case, in use, the
tuning apparatus is mounted on the musical instrument, thereby eliminating
an impedimental cord used for inputting a signal from the musical
instrument and noise induced on the cord.
Still another object of the present invention is to provide a tuning
apparatus which is able to tune a musical instrument without being
restricted to an instrument using metal chords.
A more specific object of the present invention is to provide a tuning
apparatus which has no electrical filter for discrimination of the octave
information.
A still other object of the present invention is to provide a tuning
apparatus without enlarging the scale of the circuit and increasing the
cost.
The above and other related objects and features of the invention will be
apparent from a reading of the following description of the disclosure
found in the accompanying drawings and novelty thereof pointed out in the
appended claims.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a block diagram of a tuning apparatus according to the present
invention;
FIG. 2 shows the frequency characteristics of the tuner case of the present
invention and a sound provided by an instrument;
FIG. 3 shows the spectrum of a sound provided by an instrument and the
spectrum of the output of the piezoelectric element mounted on the tuning
apparatus inputted the sound to be tuned;
FIG. 4 schematically shows the assembly of the tuning apparatus of the
present invention;
FIG. 5 is a sectional view of a tuning apparatus according to the present
invention;
FIGS. 6, 7, 8 and 9 are sectional views of the piezoelectric element
mounted on the tuning apparatus according to the present invention;
FIG. 10 is a perspective view of the tuning apparatus used for a Taisho
lyre;
FIG. 11 shows a tuning apparatus according to the present invention mounted
on an acoustic guitar;
FIG. 12 shows a tuning apparatus according to the present invention mounted
on the head of the acoustic guitar shown in FIG. 11.
FIG. 13 is a block diagram of a tuning apparatus according to the prior
art; and
FIG. 14 shows a tuning apparatus having an electromagnetic pickup according
to the prior art.
DESCRIPTION OF THE PREFERRED EMBODIMENT
An embodiment of the present invention will be explained with reference to
the accompanying drawings. FIG. 1 is a block diagram of a tuning device
according to the present invention. The tuning device is placed on a
musical instrument or mounted on the instrument by means of a suction
member or the like. When the musical instrument is tuned by a player, a
vibration produced by the instrument body is transmitted to a sensor 1,
e.g. piezoelectric element 20, mounted on a tuner case as shown in FIG. 4.
The tuner case has a specific resonance frequency. Due to the resonance
frequency characteristic of the tuner case, the frequency component of the
vibration which is higher than the fundamental wave component is removed.
That is, the tuner case has the same function as the filter 24 shown in
FIG. 13 which is necessary for detecting an octave in the prior art. The
vibration which is close to the fundamental wave component alone is
transmitted to the sensor 1, e.g. piezoelectric element 20, mounted on the
case of the tuning apparatus, and an electric signal which corresponds to
the vibration is output from the piezoelectric element 20. A wave shaping
circuit 2 converts the electric signal output from the piezoelectric
element into a signal which can be processed by a pitch calculation
circuit 3. The pitch calculation circuit 3 is comprised of a custom IC or
a microprocessor, and detects a deviation of the sound to be tuned from a
reference tone and the pitch name and the octave of the sound on the basis
of the reference signal output from a reference signal generation circuit
4 and outputs the data to a display 6 through a display driving circuit 5.
The display 6 is comprised of a meter, LED or liquid crystal panel and
displays the data.
FIG. 2 shows the resonance frequency characteristic 13 of the tuner case of
the present invention and the frequency characteristic 12 of the
instrument to be tuned. It is known that every instrument has its own
frequency characteristic, which is the main factor in making the tone
intrinsic to the instrument. For example, in FIG. 2, the frequency
characteristic of a musical instrument which will be described later is
shown. It shows that with respect to the sound having a frequency of the
fundamental wave component f2, the triple wave component 3f2 is strongest,
and with respect to the sound having a frequency of the fundamental wave
component f1, the double wave component 2f1 is strongest. When the
vibration of the instrument having such a frequency characteristic is
received by the tuning apparatus having the frequency characteristic 13,
the frequency characteristic 13 of the tuner case functions similarly to a
low-pass filter, and the vibration is passed or amplified in the region A,
attenuated in the region B and cut in the region C. In order to positively
discriminate the octave by the tuning apparatus, it is necessary that the
peak of the frequency characteristic of the tuner case be lower than the
lowest note of the instrument being tuned. The resonance frequency of the
tuner case is mainly determined by the size, thickness, shape and material
of the case. It has been made clear both experimentally and theoretically,
for example, that the increase in the size or the thickness of the case
decreases the resonance frequency, so that it is possible to make a tuning
apparatus for a specific instrument by adjusting the resonance frequency
of the tuning apparatus to the frequency characteristic of the instrument
being detected such as a guitar and a piano.
FIGS. 3A, 3B, 3C and 3D show the spectra of the vibration of the instrument
to be tuned and the spectra of the vibration output as electric signals
from the piezoelectric element 20 through the tuner case. FIG. 3A shows
the spectra of the vibration of the sound f1 of the instrument having the
frequency characteristic 12 shown in FIG. 2. It is shown that since the
fundamental wave 14 is smaller than the double wave 15, when the sound is
tuned by the spectrum component as it is, there is a possibility of being
mistaken for the sound of the double wave 15 one octave higher. FIG. 3B
shows the spectra of signals output as electric signals from the
piezoelectric element 20 provided the vibration of the instrument through
the tuner case has the frequency characteristic 13 shown in FIG. 2. Due to
the tuner case, the output signal assumes the same state as the state of
having passed through a filter having the frequency characteristic 13.
That is, the fundamental wave 14 is passed or amplified, while the double
wave 15 is attenuated or cut, thereby enabling the correct discrimination
of the octave. FIG. 3C shows the spectra of the vibration of the sound of
f2 of the instrument having the frequency characteristic 12. It is shown
that since the fundamental waver 14 is smaller than the triple wave 16,
when the sound is tuned by the spectrum component as it is, there is a
possibility of being mistaken for the sound of C five degrees higher when
the fundamental wave 14 is C, for example. By using the tuning apparatus
of the present invention, since the fundamental wave 14 is amplified, the
double wave is attenuated and the triple wave 16 is almost cut, it is
possible to correctly discriminate the pitch name.
FIG. 4 shows the assembly of the tuning apparatus of the present invention.
Between a plastic front caes 17 and a plastic rear case 19, a substrate 18
with electronic parts provided thereon is held by a holding member not
shown. The plastic front case 17 has a display unit such as a liquid
crystal display, LED display or a meter. A mounting member 22 having a
shock absorbing effect such as a rubber foot and a sucker is provided on
the rear case 19 to contact with the instrument to be tuned. The mounting
member 22 serves to prevent the noise which would be produced when the
tuner case is directly in contact with the instrument and to prevent the
vibration mode of the tuning apparatus and instrument from being changed.
The piezoelectric element 20 pasted to a metal vibrating plate 21 is
bonded to the inside of the rear case 19.
FIG. 5 shows a sectional view of another embodiment of the tuning apparatus
according to the present invention. The substrate 18 with electronic parts
thereon is held in a plastic case 30 by a holding member not shown. A
vibration inputting member 31 made of rubber is mounted on a recess 30A of
the case 30 for picking up the vibration provided by the musical
instrument to be tuned. The piezoelectric element 20 pasted to the metal
vibrating plate 21 is bounded to the inside of the case 30 corresponding
to the vibration inputting member 31. A sucker 28 for mounting the tuning
apparatus on the musical instrument is mounted with a cock 29 on a surface
portion 3B of the case 30.
FIGS. 6, 7, 8 and 9 show sectional views of the piezoelectric element
mounted on the tuning apparatus. Lead wires (not shown) are connected to
the waveform shaping circuit 2 and the ground. In FIG. 6, the reference
numeral 17 represents a front case and 18 a substrate with electric parts
provided thereon. To a plastic rear case 19, a metal vibrating plate 21
with a piezoelectric element 20 pasted thereto is adhered by an adhesive
tape or the like. In FIG. 7, a projection 19A for receiving a
piezoelectric element 20 is provided on the rear case 19 in such a manner
as to secure the periphery of the metal vibrating plate 21. In FIG. 8, a
projection 19B having a concave portion is provided on the rear case 19 in
such a manner as to secure one side of the vibrating plate 21. In FIG. 9,
a projection 19C is provided on the rear case 19 in such a manner as to
secure a rectangular parallelopiped piezoelectric element 20 in the state
of being embedded in the projection 19C. The resonance frequency of the
piezoelectric element itself can be changed by changing the metal
vibrating plate 21 pasted on the piezoelectric element 20.
FIG. 10 is a perspective view of the tuning apparatus of the present
invention used for a Taisho lyre. Since a Taisho lyre is an instrument in
which the same pitch notes are tuned in different octaves, the function of
discriminating the octave is very useful to a beginner. When a tuning
apparatus 24 of the present invention is placed on the surface place 23 of
the lyre, the vibration of the picked chord is received by the tuning
apparatus 24, which displays an octave information and a pitch deviation.
The resonance frequency of the tuning apparatus may be adjusted in
accordance with the instrument being tuned in the form of a synthesized
frequency characteristic by fixing the same material as the case, a metal
plate or the like to the tuner case.
FIG. 11 shows a tuning apparatus 33 according to the present invention
mounted on an acoustic guitar. In FIG. 11, the tuning apparatus 33 is
mounted on the side plate of an acoustic guitar 34 by a sucker 28, but it
may also be mounted on the surface plate or the back plate. When a chord
is picked by player, the vibration of the picked chord is received by the
piezoelectric element mounted on the inner surface of the tuning apparatus
through a vibration inputting member 31.
FIG. 12 shows the tuning apparatus 33 according to the present invention
mounted on the head of the acoustic guitar 35 shown in FIG. 11. The
reference numeral 35 represents a head, which is a part of the acoustic
guitar 35.
As explained above, according to the present invention, by mounting the
tuning apparatus having a piezoelectric element on the inner surface of
the tuning apparatus, the tuning apparatus has an effect of improving the
tuning efficiency without being influenced by the noise around the
instrument. In addition, since the resonance frequency of the tuner case
is adjusted to the frequency being lower than the lowest note of the
musical instrument to be tuned, no filter is used which is necessary for
discrimination of the octave in the prior art, and it is possible to
correctly discriminate the octave and the pitch name without enlarging the
scale of the circuit and increasing the cost.
Furthermore, there is no need to take a trouble of bringing the tuning
apparatus close to the chord of the instrument with one hand in tuning
unlike a conventional tuning device having a build-in electromagnetic
pickup, thereby enabling the operability to be improved.
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