JPH08115080A - Automatic string adjusting device - Google Patents

Abstract

PURPOSE: To facilitate the string adjustment and carrying operations by making the device a handy type and to prevent the breaking of the string during the string adjusting operation. CONSTITUTION: An automatic string adjusting device 1 is a handy type and consists of a motor section 2, an automatic string adjusting device (a main body) 3 and a cable 4 which electrically connects the sections 2 and 3. The section 2 has a casing, a motor 13, a rotary driving force transmission mechanism and clamps. The main body 3 has a control means 30, a string sound- electric signal converting means 31, an operating section 32, a display section 33 and a motor driving circuit 34. When a string is pulled during a string adjustment operation, the means 30 drives the motor 13 so that an input frequency becomes within an allowable range of a target frequency based on the input frequency and the target frequency for the string adjustment and the motor 13 stops when the amount of the variation in the input frequency becomes lower than a threshold value.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention automatically adjusts a musical instrument having a plurality of strings and a plurality of string winding knobs around which the strings are respectively wound (hereinafter typically referred to as a string instrument). The present invention relates to an automatic stringing device that can be used, and more particularly to an automatic stringing device that is particularly suitable for use in a Taisho koto.

[0002]

2. Description of the Related Art In a stringed instrument having a plurality of strings such as a guitar, a violin, a Taisho koto, and a piano, those strings are precisely tuned to a predetermined chord in order to produce a correct sound. is necessary. In particular, when a large number of players play the same piece of music with the same musical instrument, it is necessary that all musical instruments are properly tuned. However, in the string tuning work of such a stringed instrument, it is necessary to accurately recognize the pitch of the sound and then finely adjust the string winding knob on which the string is wound to a correct sound by hand. This is a difficult task for a person with a weak pitch.

Therefore, various devices have been proposed for tuning a stringed instrument. For example, the frequency of the original sound of each string is set in advance on the scale, the frequency when the string to be tuned is played is displayed with a pointer, etc., and the pointer is displayed on the scale indicating the original frequency of the string. There is a tuning device that indicates that the strings have been correctly tuned when they match.

However, such a device merely indicates whether or not the pitch, that is, the frequency of the string to be tuned matches the frequency of the chord that the string originally should have. Therefore, in order to tune correctly with this device, look at the deflection of the pointer while playing the string with one hand, and then finely tune the string winding knob around the string so that the deflection of the pointer matches the reference scale. Adjustment work is required. There is a problem that it is difficult for elderly beginners and the like to finely adjust the string winding knob while observing the deflection of the pointer, and it takes a long time even if it is possible.

In particular, the Taisho koto is a musical instrument for the masses and is often learned by elderly people. Therefore, many people cannot tune well with a string tuning device using such a display with a deflection of the pointer. In addition, since many players play the same song, all kotos must be tuned accurately, so in the Taisho koto classroom, most of the time is spent tuning by the instructor. The reality is that they will get hurt.

In view of the above problems, some automatic tuning devices have been proposed which can automatically tune the strings of a stringed instrument. For example, the device disclosed in Japanese Patent Laid-Open No. 56-32185 is known. ing.

In this device, a reference frequency is set in advance, a motor is rotated while the string is being played so that the frequency of the string is synchronized with the reference frequency, and the rotation of the motor is reduced by a speed reduction mechanism. I told the winder installed in
Winding or loosening the strings directly with the winder,
Thereby, the tension of the string is adjusted.

However, in this device, as described above, the strings are directly wound or loosened by the rotation of the motor, and the motor and the winder are built in the main body of the stringed instrument. Incorporating this kind of tuning mechanism inside the musical instrument not only increases the cost of the musical instrument, but it is not necessary for those who can tune themselves, and it limits the users of the musical instrument. become. In addition, such tuning work is usually required before starting playing the instrument, and after the strings have been set correctly,
It can be said that it is not necessary to equip the musical instrument with such a tuning device. Therefore, there is a demand for an automatic stringing device that is detachably attached to the instrument body that can be used only when necessary, that is, only when performing string tuning work before starting playing the instrument.

[0009]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and its main purpose is to be able to be used by attaching it to a stringed instrument only when tuning the string, and in addition to the operation and the operation at the time of tuning. It is to provide a handy type automatic tuning device that is easy to carry. Another object of the present invention is to provide an automatic tuning device that can prevent string breakage during string tuning.

Another object of the present invention is to provide an automatic tuning device with high tuning accuracy. Another object of the present invention is to provide a handy type automatic tuning device that is particularly suitable for tuning a Taisho koto and can be shared by a plurality of Taisho koto.

[0011]

The above objects are achieved by the present invention described in (1) to (10) below.

(1) An automatic tuning device capable of automatically tuning a musical instrument having a plurality of strings and a plurality of string winding knobs around which the strings are wound, the casing comprising: a casing; A motor installed in a casing, a fitting member that fits into the string winding knob and can transmit a rotational force to the string winding knob, and the casing for transmitting the rotational driving force of the motor to the fitting member. A rotary sound driving force transmission mechanism, a control means for controlling the drive of at least the motor, and a string sound-electric signal conversion for converting the input string sound into an electric signal corresponding to the frequency. Means for transmitting the rotation driving force of the motor to the string winding knob fitted to the fitting member via the rotation driving force transmitting mechanism and the fitting member to rotate the string winding knob. Wound around It is configured to be able to adjust the tension of the applied string, the control means, during tuning, the frequency of the string sound input from the string sound-electrical signal converting means, to the preset target frequency of the string tuning. It operates so as to drive the motor so as to approach, and changes the tension of the string, and determines whether the string sound input from the string sound-electrical signal converting means is a string sound from the string to be tuned, An automatic string tuning device, which is controlled to prohibit string tuning when it is determined to be a string sound from an outside string.

(2) The judgment by the control means is
The amount of change in the frequency of the string sound input from the string sound-electrical signal converting means is compared with a preset threshold value, and when the amount of change is less than or equal to the threshold value, the input string sound is adjusted. The automatic tuning device according to (1) above, which determines a string sound from a string that is not a string target.

(3) An automatic tuning device capable of automatically tuning a musical instrument having a plurality of strings and a plurality of string winding knobs around which the strings are wound, the casing comprising: a casing; A motor installed in a casing, a fitting member that fits into the string winding knob and can transmit a rotational force to the string winding knob, and the casing for transmitting the rotational driving force of the motor to the fitting member. A rotary sound driving force transmission mechanism, a control means for controlling the drive of at least the motor, and a string sound-electric signal conversion for converting the input string sound into an electric signal corresponding to the frequency. Means for transmitting the rotation driving force of the motor to the string winding knob fitted to the fitting member via the rotation driving force transmitting mechanism and the fitting member to rotate the string winding knob. Wound around It is configured to be able to adjust the tension of the applied string, the control means, during tuning, the frequency of the string sound input from the string sound-electrical signal converting means, to the preset target frequency of the string tuning. An automatic string tuning apparatus, which drives the motor so as to approach the string and operates to change the tension of the string, and controls to perform the string tuning based on a string sound generated during a stable period of the string sound.

(4) The automatic tuning according to the above (3), wherein the control means controls the tuning based on a string tone excluding a string tone generated at least at an initial stage of the string tone generation and at an end of the string tone generation. apparatus.

(5) An automatic tuning device capable of automatically tuning a musical instrument having a plurality of strings and a plurality of string winding knobs around which the strings are wound, the casing comprising: a casing; A motor installed in a casing, a fitting member that fits into the string winding knob and can transmit a rotational force to the string winding knob, and the casing for transmitting the rotational driving force of the motor to the fitting member. A rotary sound driving force transmission mechanism, a control means for controlling the drive of at least the motor, and a string sound-electric signal conversion for converting the input string sound into an electric signal corresponding to the frequency. Means and a tuning precision setting means for setting the tuning precision, and the rotary driving force of the motor is fitted to the fitting member via the rotary driving force transmission mechanism and the fitting member. The string winding knob Is configured to be able to adjust the tension of the string wound around the string knob,
During tuning, the control means drives the motor to change the tension of the string so that the frequency of the string sound input from the string sound-electrical signal converting means approaches a preset target frequency of the string tuning. The automatic tuning device is characterized in that the tuning operation is performed as described above, and the tuning speed is controlled by changing the rotation speed of the fitting member according to the tuning accuracy set by the tuning accuracy setting means.

(6) The automatic tuning device according to the above (5), wherein the tuning accuracy is within an allowable frequency range.

(7) An automatic tuning device capable of automatically tuning a musical instrument having a plurality of strings and a plurality of string winding knobs around which the strings are respectively wound, and which is held by one hand. A casing for obtaining, a motor installed in the casing, a fitting member that is fitted to the string winding knob and can transmit a rotational force to the string winding knob, and a rotational driving force of the motor is transmitted to the fitting member. For transmitting the rotational driving force, a control means for controlling the drive of at least the motor, and a string sound, and converts the input string sound into an electric signal corresponding to the frequency. A string sound-electrical signal converting means, and transmits the rotation driving force of the motor through the rotation driving force transmission mechanism and the fitting member to the string winding knob fitted to the fitting member for rotation. The above The control means is configured to adjust the tension of the string wound around the string winding knob, and the control means controls the frequency of the string sound input from the string sound-electrical signal converting means during the tuning of the string tuning preset. An automatic tuning device, characterized in that it drives the motor so as to approach a target frequency and operates so as to change the tension of the string.

(8) The fitting member is configured such that a pair of wall portions having curved concave surfaces are arranged such that the curved concave surfaces face each other, and the string winding knob is fitted between both wall portions. The automatic tuning device according to any one of (1) to (7) above.

(9) The fitting member further has a curved concave surface on the inner bottom surface of the fitting member.
The automatic tuning device described in.

(10) The control means and the string tone-
The electric signal converting means are respectively installed in the main body of the automatic stringing device, which is separate from the casing, and the motor installed in the casing and the control means installed in the main body of the automatic stringing device. The automatic tuning device according to any one of (1) to (9) above, which is configured to communicate by wire or wirelessly.

[0022]

When the string instrument is tuned, the automatic tuning device 1 of the present invention is used.
The motor part 2 of 1 is gripped with one hand, and the clamp 26 is fitted to the string winding knob 51 around which the string to be tuned is wound.

In such a state, that is, when the motor section 2 is fixed with one hand and the string to be tuned is played with the other hand, the frequency of the string is changed to the string sound / electrical signal converting means 3.
1 is input to the control means 30, and the control means 30 performs a predetermined arithmetic processing and the like until a predetermined target frequency is within an allowable range (including a case where the center frequency of the target frequency matches). 13 is rotated in a predetermined direction.
The rotation driving force of the motor 13 is transmitted to the clamp (fitting member) 26 via the rotation driving force transmission mechanism 15 and further transmitted to the string winding knob 51 via the clamp 26.
As a result, the string winding knob 51 rotates until the string wound around it reaches the correct sound, and the tuning is completed.

[0024]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The automatic tuning device of the present invention will be described below in detail with reference to the preferred embodiments shown in the accompanying drawings. 1 and 2 are respectively a perspective view showing a configuration example of an automatic stringing device of the present invention and a cross-sectional view showing a configuration example of a motor section of the automatic stringing device of the present invention. As shown in FIG. 1, an automatic stringing device 1 of the present invention is a handy type automatic stringing device, and includes a motor unit 2, an automatic stringing device main body (hereinafter referred to as a main body) 3, and a motor unit 2. It is composed of a cable 4 for electrically connecting to the main body 3.

The string winding knob mounting portion 50 of the pillow portion of the Taisho koto 5 to be tuned by the automatic string tuning device 1,
Six string winding knobs 51 are divided into left and right three pieces and arranged at predetermined intervals. A string (not shown) is wound around each of these string winding knobs 51.

As shown in FIG. 2, the motor section 2 of the automatic stringing apparatus 1 has a casing 6 (a relatively small size) that can be held by one hand. The casing 6 is a substantially cylindrical member that is open only at one end (lower side in FIG. 2), and the bottom plate 7 is installed in the opening 61 of the casing 6.

In the inside of the casing 6, that is, on the upper side of the bottom plate 7 in FIG. 2, a column (spacer) 8 provided at an end of the bottom plate 7 and a shaft 1 provided substantially at the center thereof.
The middle plate 9 is installed via the 7 and 18. In addition, a pillar (spacer) 10 is provided on the upper side in FIG. 2 substantially at the center of the middle plate 9, and the upper plate portion 62 of the casing 6 is provided.
Is joined to one end of the column 10. Thus, in the casing 6, the 1st area | region 63 and the 2nd area | region 64 partitioned by the intermediate plate 9 are formed.

In the second area 64, the jack mounting plate 11 is installed at the end of the intermediate plate 9, and the jack mounting plate 1
1 is a jack (connector) to which the cable 4 is connected
12 is attached. In the second area 64,
The motor 13 is installed on the middle plate 9. In this case, the rotary shaft 14 of the motor 13 moves from the hole of the intermediate plate 9 to the first region 63.
The gear 16 is joined to the tip of the rotary shaft 14.

The rotational driving force from the motor 13 is decelerated via the rotational driving force transmission mechanism 15 provided in the first region 63 and transmitted to the clamp (fitting member) 26 which is a driven member. The clamp 26 is configured to be rotatable in both forward and reverse directions.

More specifically, the rotary driving force transmission mechanism 15 includes two rotary driving force transmission mechanisms 15 disposed between the middle plate 9 and the bottom plate 7 in the same direction (parallel) as the rotation shaft 14 of the motor 13. Axis 17
Gears 19, 20, 21 and 22 rotatably attached to the motors 18 and 18, respectively, and a clamp rotary shaft which is rotatably supported and arranged in the same direction (parallel) as the rotary shaft 14 of the motor 13. 25 and the clamp rotating shaft 25
The gear 23 fixed by the pin 24 and the gear 16
And have. More specifically, the gear 16 of the motor 13
2, a gear 19 on the upper side of the shaft 17 in FIG. 2 meshes with the gear 19, and a gear 21 on the upper side of the shaft 18 in FIG. 2 meshes with the gear 19.
The gear 21 includes a gear 20 on the lower side of the shaft 17 in FIG.
2 meshes with the gear 20, and a gear 21 on the lower side of the shaft 18 in FIG. 2 meshes with the gear 20, and a gear 23 of the clamp rotation shaft 25 meshes with the gear 21. The rotation of is slowed down and transmitted.

Each gear 1 of this rotary driving force transmission mechanism 15
The gear ratios of 4, 19, 20, 21, 22 and 23 are respectively set so that the rotation of the motor 13 is decelerated and transmitted so that the clamp rotation shaft 25 rotates about once every 10 to 20 seconds. Is preferred. Clamp rotating shaft 25
Has one end protruding from the hole of the bottom plate 7 to the outside of the casing 6, and a clamp 26 is joined to one end of the clamp rotating shaft 25.

3 and 4 are a side view and a bottom view, respectively, showing an example of the structure of the clamp 26 of the automatic stringing device 1. As shown in FIGS. 3 and 4, the automatic tuning device 1
In the clamp (fitting member) 26, a pair of wall portions 27 and 28 having curved concave surfaces 271 and 281 curved with a predetermined curvature are arranged so that the curved concave surface 271 and the curved concave surface 281 face each other, and the wall portion 27. Between the wall and the wall 28
It is made of a substantially U-shaped metal piece configured to be fitted with the string winding knob 51. The lower end of the clamp rotating shaft 25 in FIG. 3 is fixed to the upper end surface of the clamp 26 in FIG.

The size of the clamp 26 is not particularly limited, but preferably, the width A of the clamp 26 is about 21 to 23 mm, and the distance B between the curved concave surface 271 and the curved concave surface 281 in the center of the clamp 26 is about 9 to 10 mm. Clamp 26
The distance C between the curved concave surface 271 and the curved concave surface 281 at both ends is set to about 4 to 6 mm.

In the case of the Taisho koto 5, there are various models in which the shape and dimensions of the string winding knob 51 are different, that is, there are several tens of shapes and dimensions of the string winding knob 51, but in the present embodiment, as described above. By constructing the clamp 26, the clamp 26 can be provided with a string winding knob 51 of various shapes and sizes.
It has a wide range of versatility. Further, when the clamp 26 is fitted into the string winding knob 51, the gap (play) between the clamp 26 and the string winding knob 51 can be reduced, and as a result, the tuning is completed with a small number of times (the number of times the string is played). be able to.

When the clamp 26 is rotated while the clamp 26 is fitted in the string winding knob 51, the rotation of the clamp 26 causes the string winding knob 51 to move to the curved concave surfaces 271 and 281 of the clamp 26, particularly both ends of the clamp 26. Guided by the curved concave surfaces 271 and 281, the center of the axis of the string knob 51 and the center of the clamp rotation shaft 25 move so as to coincide with each other. This stabilizes the tuning operation.

Next, another example of the structure of the clamp (fitting member) will be described. 9 and 10 are a side view and a bottom view, respectively, showing another configuration example of the clamp of the automatic tuning device 1. Clamp 26 shown in FIGS. 9 and 10.
“A” has a more preferable structure than the clamp 26 described above, and the inner bottom surface of the clamp 26 has a curved concave surface. Hereinafter, a specific description will be given.

The clamp 26a has a pair of wall portions 2 having curved concave surfaces 271a and 281a curved with a predetermined curvature.
7a and 28a and a curved concave surface 2 curved with a predetermined curvature
It is composed of a substantially U-shaped metal piece constituted by the ceiling portion 29a having 91a. In this case, both wall portions 27a and 28a are arranged so that the curved concave surface 271a and the curved concave surface 281a face each other, and the ceiling portion 29a has the curved concave surface 291a on the lower side in FIG. 9 (on the side opposite to the clamp rotation shaft 25). ), The string winding knob 51 of the Taisho koto 5 is fitted between the wall portion 27a and the wall portion 28a. The ceiling 29a of the clamp 26a
9, the lower end of the clamp rotation shaft 25 in FIG. 9 is fixed.

The size of the clamp 26a is not particularly limited, but preferably the width A _{1 of the} clamp 26a is 20 to 2.
4 mm, curved concave surface 27 in the center of the clamp 26a
1a and the curved concave surface 281a have a distance B ₁ of about 8 to 10 mm, the distance C ₁ between the curved concave surface 271a and the curved concave surface 281a at both ends of the clamp 26a is about 4 to 6 mm, and the height D ₁ at the center of the clamp 26a is 10 mm. Approximately 15 mm.

The casing 6 of the automatic tuning device 1 is
The structure is not limited to the one shown in the figure, and in addition to this, for example, it may have a separate grip portion that can be gripped with one hand. Further, the rotary drive force transmission mechanism 15 of the automatic stringing device 1 is not limited to the one shown in the figure, but other than this, for example, a rotary drive only, that is, the motor 13 and the clamp 2.
6 may be directly connected.

Further, the rotational driving force transmission mechanism 15 may have, for example, a gear mechanism in which the gear ratio is variable and the torque and the rotational speed can be changed by changing the gear ratio. In this case, by increasing the torque by the transmission mechanism, it is possible to tune a musical instrument requiring a large torque, such as a piano, and the versatility is expanded.

The clamp of the automatic tuning device 1 is shown in FIG.
The shape shown in FIG. 4 and the shape shown in FIG. 9 and FIG. 10 are particularly preferable, but the shape is not limited to that shown in the figure. The shape may be any shape as long as the rotational force of the motor 13 can be transmitted to the string knob 51.

Further, in this embodiment, the clamp 26 (26
Although a) is fixed to the rotary shaft 25, the present invention is not limited to this, and the clamp may be detachably (replaceable) in addition to this. In this case, when tuning other stringed instruments, the clamps can be exchanged according to the type of the stringed instrument, so that versatility is further expanded.

Next, the circuit of the automatic tuning device of the present invention will be described. FIG. 5 is a block diagram showing a circuit configuration example of the automatic tuning device of the present invention. As shown in the figure, the main body 3 of the automatic tuning device 1 has a control means 30, a string sound-electrical signal conversion means 31, an operation part 32, a display part 33, and a motor driver circuit 34. There is. The motor driver circuit 34 uses the cable 4 to connect the motor unit 2 to the motor unit 2 as described above.
Is electrically connected to the motor 13.

The string sound-electrical signal converting means 31 is a means for receiving a string sound generated when a string is played, and converting the input string sound into an electric signal (electric signal) corresponding to the frequency thereof. For example, it is composed of a microphone and an amplifier circuit. On the output side of the string sound-electrical signal converting means 31,
The control means 30 is connected, and the signal from the string sound-electrical signal conversion means 31 is input to the control means 30.

The control means 30 is usually composed of a microcomputer (MCU), and based on a signal from the string sound-electrical signal conversion means 31 and the like, a motor driver circuit 34 connected to the control means 30 drives a motor. 13 drive control, that is, the tuning control described later, control for preventing string breakage, control of the rotation speed of the motor 13, and the like,
It controls various functions in the automatic tuning device 1 such as a string break warning display and a tuning end display which will be described later. Further, the control means 30 has a memory, a timer, a counter, etc., which are not shown.

An operating section 32 is connected to the control means 30. This operation unit 32 has a target frequency, that is,
Target octave setting (selection) switch for setting (selecting) a target octave for string tuning and scales (C, C #, D, D #, E, F, F #, G) targeted for string tuning.
G #, A, A #, B) for setting a target scale setting switch, a reference frequency setting switch for setting a reference frequency f ₀ which will be described later, tuning accuracy, that is, a width of an allowable range of the target frequency. Allowable range width setting switch (string tuning accuracy setting means) for setting, string break prevention mode setting switch set to "string break prevention mode" for performing string break prevention control described later when the switch is turned on, and string tuning is prohibited If necessary, a tuning inhibition canceling switch (end cancellation switch) for canceling the tuning prohibition, a main switch, and the like are provided as necessary. Here, the target frequency means a correct frequency of a string (string sound) to be tuned.

The reference frequency f ₀ is a reference frequency of all the scales in each octave. For example, the reference frequency f ₀ is a scale A in a predetermined octave.
And the reference frequency f _{0 is set} to, for example, 438, 439,
440, 441, 442, 443, 444 and 445
It is configured so that it can be arbitrarily selected from Hz. When the reference frequency f ₀ is set, the center frequencies of all the scales in each octave are determined. Therefore, when the target octave and scale are set by the target octave selection switch and the target scale selection switch, The center frequency of the scale in the octave, that is, the center frequency of the target frequency is set.

A display unit 33 is connected to the control means 30. The display unit 33 displays a string break warning display, a tuning end display, a reference frequency f ₀ set by a reference frequency setting switch, a target octave selection switch and a target octave of the tuning set by a target scale selection switch, which will be described later. And scale, that is, target frequency, width of the permissible range of the target frequency set by the permissible range width setting switch (string tuning accuracy), signal input from the string sound-electrical signal converting means 31 to the control means, that is, The octave value, scale and input frequency of the string sound input from the string sound-electrical signal converting means 31 are smaller than the minimum value of the allowable range of the target frequency / greater than the maximum value of the allowable range of the target frequency / within the allowable range of the target frequency. / Whether there is no input signal, the necessary information of the difference (deviation amount) between the input frequency and the center frequency of the target frequency, etc. But, for example, light emitting elements such as light emitting diode (LED), a liquid crystal display element (L
CD), meter, etc.

Next, the circuit operation of the automatic tuning apparatus 1 at the time of tuning will be described. The user (string adjuster) operates each switch of the operation unit 32 of the automatic string adjusting device 1 to perform a predetermined setting as described below. First, with the reference frequency setting switch,
When the reference frequency (f ₀ ) is set and the target octave setting switch and target scale setting switch are used to set the target octave value for tuning and the target scale for tuning, the center frequency (f _A ) of the target frequency is set. Is set.

Then, with the allowable range width setting switch,
When the width of the target frequency permissible range (± a) is set, the target frequency permissible range (f _A −a to f _A + a), that is,
Minimum value of the allowable range of the target frequency (f _A -a = f _min) and maximum _{(f A + a = f ma} x) is set.

Further, the set reference frequency (f
₀ ), target octave value and scale of tuning, width of target frequency tolerance range (± a), center frequency of target frequency (f _A ), minimum value of target frequency tolerance range (f _min ).
And the maximum value of the allowable range of the target frequency (f _A + a = f
_max ) is displayed on the display unit 33.

After the setting of the automatic tuning device 1 is completed in this way, as shown in FIG. 1, the casing of the motor unit 2 is gripped and the clamp 26 is wound around the string to be tuned. Fit the string winding knob 51 and play the string to be tuned. Hereinafter, the strings wound around the string winding knob 51 with which the clamp 26 of the motor unit 2 is fitted are referred to as “strings to be tuned”, and the other strings are referred to as “strings not to be tuned”.

As shown in FIG. 5, a string sound generated when a string is played is input to the string sound-electrical signal converting means 31, and the string sound-electrical signal converting means 31 generates an electrical sound corresponding to the frequency of the string sound. The signal is converted into a different signal, and this signal is input from the string sound-electrical signal conversion means 31 to the control means 30. The control means 30 detects the string sound based on the input signal from the string sound-electrical signal conversion means 31, that is, obtains the input frequency. This input frequency is displayed on the display unit 33.

Further, the control means 30 judges whether or not the input signal satisfies a predetermined input condition, and when it judges that the input signal satisfies the input condition, the control means 30 determines that "input is present" and performs each calculation described later. Perform processing and display. On the other hand, if it is determined that the input condition is not satisfied, it is set as “no input”. As a result, malfunction of the device due to external noise can be prevented.

Here, the input condition is a condition for the input signal to be recognized as a signal based on a string sound, and is preset at the time of factory shipment of the automatic string tuning apparatus 1.
It should be noted that this input condition is, for example, "the volume of the input sound is a predetermined value or more", "the stability of the input sound is a predetermined value or more", and the like so that noise pickup during string tuning is excluded. Set the conditions to.

When the control means 30 determines that the input signal from the string sound-electrical signal converting means 31 satisfies the input condition, the input signal from the string sound-electrical signal converting means 31 and the preset signal are set. The tuning of the strings is controlled based on the target frequency. FIG. 6 shows the control means 30 during tuning.
3 is a timing chart showing the motor control operation of FIG. Actually, the motor operation timing is slightly shifted to the right side in FIG. 6 due to the calculation time or the like, but the calculation time or the like is omitted for simplicity.

As shown in the figure, the string sound (input waveform) when a string is played is not a continuous and beautiful sine wave. The period t _{1 in the} initial stage of generation of the string sound is a convergence period until the strings resonate, and a disturbed waveform is generated. It is difficult to detect the string sound during this period, and the tuning accuracy is low. In addition, the period t _{3 at the} end of generation of the string sound is a period during which the resonance of the string is attenuated,
A continuous sine wave is generated, but its amplitude is small,
In addition, a lot of sounds of other strings having the same resonance frequency are included. Therefore, the tuning accuracy in this period is low.

On the other hand, the period t ₂ in the middle period of string sound generation is
This is a period during which the strings are resonating, and a continuous sine wave having a relatively large amplitude is generated, so that the string sound can be easily detected and the tuning accuracy is high.

Therefore, in the present embodiment, tuning is performed based on the string sound generated during the stable period of the string sound. Specifically, the driving (tuning) of the motor 13 is stopped (prohibited) during at least one of the periods t ₁ (the beginning of string sound generation) and t ₃ (the end of string sound generation), and at least one of the periods t ₁ and t ₃ . Tuning is performed based on the string sound excluding the string sound generated in. Preferably, in the periods t ₁ and t ₃ , the driving of the motor 13 is stopped, and the tuning is performed based on the string sound generated in a predetermined period within the period t ₂ (the middle period of string sound generation). That is, the period t ₂
The motor 13 is allowed to drive only within a predetermined period, and the tuning is performed.

In this case, in this embodiment, the period t ₄ (> t)
₁₎ prohibits tuning, after this, during the period t _5, to allow tuning for a certain period (the period t ₅₎ passes after the start of the該調strings prohibits tuning. That is, the period t ₄ (> t)
_{At 1} ) and t ₆ (> t ₃ ), the drive of the motor 13 is stopped, the drive of the motor 13 is permitted only during the period t ₅ , and the tuning is performed. Note that t ₁ + t ₂ > t ₄ + t ₅ , t ₁ + t ₂ + t
₃ = t ₄ + t ₅ + t ₆ . Also, t ₄ is 0.1 to
About 1 second, t ₅ is about 0.5 to 4 seconds, and t ₄ + t ₅ is
It is preferably about 0.6 to 5 seconds. The above t ₄
And t ₅ are appropriately determined according to the type of stringed instrument and the like.

In the present embodiment, by controlling the tuning period in this way, the accuracy of string sound detection is improved, and as a result,
Since the input frequency can be accurately obtained, the tuning accuracy is improved.

For example, when the tuning is performed during the entire period from t _{1 to} t ₃ , the tuning precision is limited to about ± 2 cent (cent), and when the precision is increased, the motor 13 is overloaded. A run (a phenomenon in which the target frequency is passed once) occurs, and the number of times the string is played is increased until the end of tuning. However, in the present embodiment, the probability of overrun is extremely small, and until the end of tuning. The number of times to play the string can be reduced, and the tuning accuracy can be improved to ± 1 cent or less.

During tuning, the control means 30 controls the motor so that the input frequency (the frequency of the string sound of the plucked string) approaches the target frequency for tuning (including the case where it matches the center frequency of the target frequency). 13 is driven to change the tension of the string to be tuned. Hereinafter, a specific description will be given. The control means 30 compares the input frequency with the target frequency for tuning. That is,
It is determined whether the input frequency is within the allowable range of the target frequency.

When the input frequency is within the permissible range of the target frequency from the beginning, the motor 13 is not rotated (driven) and the tuning is ended. In this case, the display unit 33
A tuning end display indicating that tuning has been completed is performed. When the input frequency is not within the allowable range of the target frequency, the control means 30 determines that the input frequency is higher than the target frequency (the maximum value f _max of the allowable range of the target frequency) or the input frequency is the target frequency (the target frequency. The minimum value f of the allowable range of
_min ).

When the input frequency is higher, that is, the input frequency is the maximum value f of the allowable range of the tuning target frequency.
If it is higher than _max , the motor 13 is rotated (driven) in the direction of loosening the string to lower the tension of the string to be tuned. When the input frequency is lower, that is, when the input frequency is lower than the minimum value f _min of the permissible range of the target frequency of tuning, the motor 13 is rotated (driven) in the string tightening direction. , Increase the tension of the string to be tuned.

The control means 30 also finds the difference between the input frequency and the center frequency f _A of the target frequency. The input frequency is lower than the minimum value f _min of the target frequency allowable range, and the input frequency is the maximum value f _max of the target frequency allowable range.
The display unit 33 displays whether the input frequency is higher than the allowable range of the target frequency or does not exist, and the difference between the input frequency and the center frequency f _A of the target frequency.

The detection of the input frequency, the comparison between the input frequency and the target frequency, and the rotation operation of the motor 13 are as follows.
Each is repeatedly performed during the period t ₅ , and the input frequency gradually approaches the allowable range of the target frequency. Then, when the input frequency is within the allowable range of the target frequency, the motor 13 is stopped and the tuning is ended. In this case, the display unit 33 displays a tuning end display indicating that the tuning is finished.

Although the tuning may be finished by only striking the string once, it is usually necessary to play the string several times until the input frequency is within the allowable range of the target frequency.
The operation described above is repeated each time. Here, for example, when the input frequency is detected for a predetermined time (for example, 0.5 to 4 seconds) within an allowable range of the target frequency for a predetermined number of times (for example, 1 to 3 times), the input frequency is It may be within the allowable range of the target frequency.

Further, in the present embodiment, the control means 30 changes the rotation speed of the motor 13 in accordance with the tuning accuracy, that is, the magnitude (± a) of the width (± a) of the allowable range of the target frequency, and thereby the clamp 26. Control to change the rotation speed of.

For example, the width of the allowable range of the target frequency is ±
1.0cent, ± 1.5cent, ± 2.0cent and ± 3.
When four types of 0cent are provided, the width of the allowable range is ±
When set to 1.0 cent or ± 1.5 cent (when the width of the allowable range is relatively small), the motor 13 is rotated at a relatively low rotation speed to set the width of the allowable range to ± 2.0 cent.
And ± 3.0 cent (when the width of the allowable range is relatively large), the motor 1 operates at a relatively high rotation speed.
Rotate 3. In addition, ± 1.0cent, ± 1.5cent,
Different rotation speeds may be associated with ± 2.0 cent and ± 3.0 cent, respectively.

As described above, the rotational speed of the motor 13 is controlled according to the magnitude of the allowable range, that is, the rotational speed of the motor 13 is set lower as the allowable range is smaller (the tuning accuracy is higher). The probability of occurrence is extremely small, and the number of times the string is played can be reduced before the end of tuning. In addition, in the present invention, in addition to the above-described configuration, for example, the clamp 2 is provided by a transmission mechanism or the like that can change the gear ratio.
The rotational speed of 6 may be changed.

The automatic tuning device 1 of this embodiment further has a string break prevention function. The control means 30 determines whether or not the input string sound is a string sound from the string to be tuned, and if it is determined to be a string sound from the string not to be tuned, controls it to prohibit the string tuning. .

When tuning a string, for example, when a string that is not a tuning target is played, the input frequency does not change no matter how many times the string is played. Therefore, the control means 30 compares the change amount of the input frequency with a preset threshold value (x), and when the change amount of the input frequency is less than or equal to the threshold value (x),
The input string sound is a string sound from a string that is not a tuning target, that is, a string that is being played and a string that is wound around a string winding knob 51 to which the clamp 26 of the motor unit 2 is fitted (a string that is a tuning target). ) Is determined to be different, and the driving of the motor 13 is prohibited.

The amount of change in the input frequency is determined by the sound when the string is played a predetermined number of times (n ₁ time) and the string n ₂ times after the predetermined number of times (n ₁ time), that is, n ₁ + n ₂ time. It is preferable to use the difference between the input frequency and the sound when played. The n ₁ and n ₂ are natural numbers. In this case, in consideration of variations in the string sound depending on how the strings are played, n ₁ is 1 to 3, particularly 1, n ₂ is 1 to
It is preferable that 6 and n ₁ + n _{2 be 2} to 9. Also,
The threshold value x is preferably about 5 to 20 cents.

To explain the string break prevention function in detail, the control means 30 controls the final input value of the input frequency when the string is first played and the string for the mth time (where m is 2).
The above integer, for example, m = 2 to 9) is compared with the final input value of the input frequency when playing, and when the difference is less than or equal to the threshold value x (for example, x = 11cent), The motor 13 is forcibly stopped and string tuning is prohibited. Then, the display unit 33 displays a string break warning. The string break warning display continues until the string tuning inhibition release switch is turned on by the operation of the stringer. Further, when the tuning prohibition release switch is turned on, the prohibition of driving of the motor 13 (prohibition of string tuning) is canceled, and the tuning becomes possible.

Here, the "final input value" means the frequency of the string sound generated at the end of the period during which the tuning is allowed (stabilization period of the string sound) (in this embodiment, t = t ₄ + t shown in FIG. 6). The frequency of the string sound in ₅ ).

In the present embodiment, the m (n ₁ + n ₂ ) in the string break prevention function is the rotation speed of the motor 13 (rotation speed of the clamp 26), that is, the width of the allowable range of the target frequency (tuned string). Accuracy). For example, when the allowable range width is set to ± 1.0 cent or ± 1.5 cent (when the allowable range width is relatively small), m = 6 (n ₂ = 5), and the allowable range width is ± 2.0cent
And ± 3.0 cent (when the width of the allowable range is relatively large), m = 3 (n ₂ = 2). The threshold values x and m (n ₁ + n ₂ ) and the like are appropriately determined according to the type of string instrument, the rotation speed of the motor 13, and the like.

As described above, when the string to be tuned is played, if the input frequency deviates from the permissible range of the target frequency, the motor 13 rotates in a predetermined direction, which gradually changes the string sound. , The motor stops when the input frequency is within the allowable range of the target frequency.

However, when tuning is performed with a device having no string breaking prevention function as described above, if a string outside the tuning target is played, if the input frequency is lower than the target frequency, the motor 13 The strings rotate in the tightening direction, which gradually tightens the strings, but the string sound does not change even if the strings are tightened. If you repeat this, the strings will be overtightened and the strings will break. When a string is broken, the broken string may hit the face or hand of the tuner and may be injured, which is extremely dangerous.

On the other hand, in the present embodiment, since the above-described string break prevention function is provided, the motor 13 is forcibly forced to play even if a string that is not a tuning target is played during tuning. Since the string is stopped and the tuning is prohibited, it is possible to prevent string breakage due to over-tightening of the string, which can reduce the string price required when the string is broken and the labor for string replacement, and especially The safety at the time of tuning can be improved.

As described above, in order to tune the next string after the tuning of one string is finished, the string to be tuned next is selected by the target octave setting switch and the target scale setting switch. Set the target octave value and scale (target frequency) of. Since the following is the same as the above, the description is omitted.

Next, the operation of the control means 30 of the automatic tuning apparatus 1 at the time of tuning will be described. FIG. 7 shows the control means 3 for tuning.
7 is a flowchart showing a control operation of 0. Hereinafter, description will be given based on this flowchart. When all the settings have been completed and the counter and timer (not shown) incorporated in the control means 30 are reset (count N = 0, timer t = 0), the string sound-
Whether or not there is an input from the electric signal converting means 31, that is,
It is determined whether the input signal from the string sound-electrical signal converting means 31 satisfies a predetermined input condition (step 10).
1).

In step 101, when it is judged that there is an input from the string sound-electrical signal converting means 31, that is, the input signal from the string sound-electrical signal converting means 31 satisfies the predetermined input condition, the counter The count N is incremented by 1 (N = N + 1) (step 10)
2). The count N corresponds to the number of times the string is played.

Then, the timer is started (t =
0) (step 103). Then, it is determined whether or not the timer t = t ₄ (step 104). In this case, for example, t ₄ = 0.2 seconds (see FIG. 6). When it is determined in step 104 that the timer t = t ₄ , the input frequency is obtained based on the input signal from the string sound / electrical signal converting means 31 (step 105).

Then, it is judged whether or not the calculated input frequency is within the allowable range of the target frequency (step 106). When it is determined in step 106 that the input frequency is not within the allowable range of the target frequency, it is determined whether the input frequency is higher than the target frequency (step 10).
7).

If it is determined in step 107 that the input frequency is higher than the target frequency (the maximum value f _max of the allowable range of the target frequency), the motor 1 is moved in the string loosening direction.
3 is rotated (step 108). Also, step 1
When it is determined in 07 that the input frequency is smaller than the target frequency (the minimum value f _min of the allowable range of the target frequency), the motor 13 is rotated in the string tightening direction (step 109).

Next, it is determined whether or not there is an input from the string sound-electrical signal converting means 31, that is, whether or not the input signal from the string sound-electrical signal converting means 31 satisfies a predetermined input condition (step 110). ). If it is determined in step 110 that there is no input, the motor 13 is stopped (step 111), after which the process returns to step 101 and the steps 101 and thereafter are executed again.

When it is judged in step 110 that there is an input, it is judged whether or not the timer t≤t ₄ + t ₅ (step 112). In this case, for example, t ₅ = 1.
It is about 0 seconds (see FIG. 6). When it is determined in step 112 that the timer t ≦ t ₄ + t ₅ , the process returns to step 105, and the steps from step 105 are executed again. In step 112, the timer t> t ₄
When it is determined to be + t ₅ , the motor 13 is stopped (step 113), after which the process returns to step 101 and the steps from step 101 onward are executed again.

When it is determined in step 106 that the input frequency is within the allowable range of the target frequency, the motor 13 is stopped and the tuning is finished (step 114). Next, the display unit 33 displays a string adjustment end (step 115). Next, the count N of the counter is reset (N = 0) (step 116). This is the end of this program.

FIG. 8 is a flow chart showing the control operation of the control means 30 during tuning in the "string break prevention mode". The tuning operation is omitted in this flowchart. Hereinafter, description will be given based on this flowchart. The string break prevention mode setting switch is turned on to set the string break prevention mode, all other settings are completed, and the counter (not shown) incorporated in the control unit 30 is reset. In the state (count N = 0), whether there is an input from the string sound-electrical signal converting means 31, that is, the string sound-electrical signal converting means 3
It is determined whether or not the input signal from 1 satisfies a predetermined input condition (step 201).

When it is determined in step 201 that there is an input from the string sound-electrical signal converting means 31, that is, the input signal from the string sound-electrical signal converting means 31 satisfies a predetermined input condition, the counter The count N is incremented by 1 (N = N + 1) (step 20)
2). The count N corresponds to the number of times the string is played.

Then, it is judged whether or not the count N of the counter is 1 (step 203). When it is determined in step 203 that the count N = 1, as described above, the tuning is permitted during the period t ₅ , the input frequency is obtained, and the input frequency is set within the allowable range of the target frequency. The motor 13 is driven to tune. At this time, the final input value of the input frequencies is stored in the memory as data for N = 1 (step 204). Then, the process returns to step 201, and steps 201 to 203 are executed again.

If it is determined in step 203 that the count N is not 1, it is determined whether the count N is 3 (step 205). When it is determined in step 205 that the count N = 3 is not satisfied,
Return to step 201 and repeat steps 201 to 205.
To execute. Further, when it is determined in step 205 that the count N = 3, as described above, the period t ₅
String tuning is permitted, the input frequency is obtained, the motor 13 is driven so that the input frequency is within the allowable range of the target frequency, and then the string is tuned. Then, the data at N = 1 is read from the memory. (Step 206).

Next, the data at N = 3 (final input value of the input frequency) and N read from the memory.
The difference α from the data at = 1 (step 20)
7). Next, it is determined whether or not the difference α ≦ 11cent (threshold value) (step 208). In step 208,
When it is determined that the difference α> 11cent, the count N of the counter is reset (N = 0) (step 209), the process returns to step 201, and step 201 and subsequent steps are executed again.

Further, in step 208, the difference α ≦ 1
If it is determined to be 1 cent, the motor 13 is forcibly stopped (step 210). Then, the display unit 33 displays a string break warning (step 211). This is the end of this program.

In the present embodiment described above, the control means 3
Although 0 is constituted by a microcomputer, the control means 30 is not limited to a microcomputer in the present invention, and may be constituted by a logic circuit, for example. Further, in the present embodiment, the "string break prevention mode" for performing string break prevention control with the string break prevention mode setting switch.
And the "normal mode" in which the string break prevention control is not performed can be selected, but the present invention may be configured such that the string break prevention control is always performed during tuning.

Further, in this embodiment, a string break prevention function and
The present invention has a function of performing tuning based on the string sound generated during the stable period of the string sound, and a function of performing tuning by changing the rotation speed of the fitting member according to the tuning accuracy. For example, it is possible to provide any one of these functions or to combine any two of the three functions. In this case, it is preferable to combine two of the three functions, rather than just one function.

As the combination pattern, "string break prevention function and function to perform string tuning based on the string sound generated during the stable period of the string sound", "string break prevention function and fitting function of the fitting member depending on the string tuning accuracy" A function to tune by changing the rotation speed ",
"A function that tunes based on the string sound generated during the stable period of the string sound, and a function that adjusts the rotational speed of the fitting member according to the tuning accuracy to tune" and "A string break prevention function and a string sound. With the function to tune based on the string sound generated during the stable period of
There is a function (this embodiment) that changes the rotational speed of the fitting member according to the tuning accuracy (this example). Among these, there are "string break prevention function and string sound generated during the stable period of string sound." This embodiment has three functions: a function for performing tuning based on the above, and a function for performing tuning by changing the rotation speed of the fitting member according to the tuning accuracy.

Further, in this embodiment, the motor section 2 and the automatic tuning device main body 3 are connected by the cable 4, and the motor 13 and the control means 30 are wiredly communicated via the motor driver circuit 34. However, in the present invention, in addition to this, for example, the communication between the motor unit 2 and the automatic tuning device body 3 (communication between the motor 13 and the control unit 30) may be performed wirelessly. In the present invention, for example, the control unit 30, the string sound-electrical signal conversion unit 31, the operation unit 32,
At least one of the display unit 33 and the motor driver circuit 34 may be provided in the motor unit 2.

Although the present embodiment has been described with respect to the case where the automatic tuning device of the present invention is used in a Taisho koto, the present invention is applicable to other string instruments such as guitar, ukulele, violin, cello, harp and shamisen. The present invention can also be applied to various musical instruments such as pianos having strings and string winding knobs (including musical instruments in which the string winding knobs are removable). The automatic tuning device of the present invention has been described above based on the illustrated configuration example, but the present invention is not limited to this.

[0101]

As described above, according to the automatic tuning apparatus of the present invention, it can be used as needed for a stringed instrument requiring tuning, and since it is a handy type, Easy to operate and carry on strings. Also, since the correct tuning can be done automatically just by activating the device and playing the strings, it is very practical, especially when playing the same song with many musical instruments. If it is used, there is no individual difference in articulation and uniform tuning is possible.

Further, according to the automatic tuning apparatus of the present invention having the string break prevention function, the motor is forcibly stopped even when a string which is not a tuning target is played at the time of tuning. Since string tuning is prohibited, string breakage due to over-tightening of strings can be prevented, which reduces the string price required when strings are broken and eliminates the labor of string replacement, and especially during string tuning. The safety can be improved.

Further, according to the automatic tuning apparatus of the present invention which tunes on the basis of the string sound generated during the stable period of the string sound, the probability of overrun is extremely small, and the number of times the string is struck by the end of string tuning is reduced. Can be reduced, and high tuning accuracy can be obtained.

Further, according to the automatic tuning apparatus of the present invention, which adjusts the rotational speed of the fitting member according to the tuning accuracy, that is, the magnitude of the allowable range of the target frequency of the tuning, the tuning is over. The probability that a run will occur is extremely small, and the number of times the string is played before the end of tuning can be reduced.

[Brief description of drawings]

FIG. 1 is a perspective view showing a configuration example of an automatic string tuning device of the present invention.

FIG. 2 is a cross-sectional view showing a configuration example of a motor unit according to the present invention.

FIG. 3 is a side view showing a configuration example of a clamp according to the present invention.

FIG. 4 is a bottom view showing a configuration example of a clamp according to the present invention.

FIG. 5 is a block diagram showing a circuit configuration example of the automatic tuning device of the present invention.

FIG. 6 is a timing chart showing an example of a motor control operation at the time of tuning the control means in the present invention.

FIG. 7 is a flow chart showing an example of control operation at the time of tuning the control means in the present invention.

FIG. 8 is a flowchart showing an example of control operation at the time of tuning the control means in the “string break prevention mode” in the present invention.

FIG. 9 is a side view showing a configuration example of a clamp according to the present invention.

FIG. 10 is a bottom view showing a configuration example of a clamp according to the present invention.

[Explanation of symbols]

 1 Automatic Tuning Device 2 Motor Part 3 Automatic Tuning Device Main Body 4 Cable 5 Taisho Koto 50 String Winding Knob Attachment 51 String Winding Knob 6 Casing 61 Opening 62 Upper Plate 63 First Area 64 Second Area 7 Bottom Plate 8 Pillar 9 Middle Plate 10 Supports 11 Jack mounting part 12 Jack 13 Motor 14 Rotating shaft 15 Rotational driving force transmission mechanism 16 Gears 17, 18 Shafts 19-23 Gears 24 Pins 25 Clamp rotating shafts 26, 26a Clamps 27, 27a Walls 271, 271a Curved concave surface 28 , 28a Wall part 8 281, 281a Curved concave surface 29 Ceiling part 291a Curved concave surface 30 Control means 31 String sound-electrical signal conversion means 32 Operation part 33 Display part 34 Motor driver circuit 101-116 Steps 201-211 steps

Claims (10)

[Claims] 1. An automatic string tuning device capable of automatically tuning a musical instrument having a plurality of strings and a plurality of string winding knobs for winding the strings, the casing comprising: a casing; and the casing. A motor installed therein, a fitting member that fits into the string winding knob and can transmit a rotational force to the string winding knob, and the casing for transmitting the rotational driving force of the motor to the fitting member A rotary driving force transmission mechanism, a control means for controlling the drive of at least the motor, and a string sound-electrical signal converting means for receiving a string sound and converting the input string sound into an electric signal corresponding to its frequency. And a rotational drive force of the motor is transmitted through the rotational drive force transmission mechanism and the fitting member to the string winding knob fitted to the fitting member to rotate, and to the string winding knob. Winding The control means is configured to adjust the tension of the generated string, and the frequency of the string sound input from the string sound-electrical signal converting means approaches the preset target frequency of the string tuning during tuning. As described above, the motor is operated to change the tension of the string, and it is determined whether the string sound input from the string sound-electrical signal converting means is a string sound from the string to be tuned, and the string tone is not tuned. When it is judged that the sound is a string sound from the string, the automatic string tuning device is controlled to prohibit string tuning. 2. The determination made by the control means compares the amount of change in the frequency of the string sound input from the string-electrical signal converter with a preset threshold value, and the amount of change is The automatic tuning device according to claim 1, wherein when the threshold value is less than or equal to the threshold value, the input string sound is determined to be a string sound from a string that is not a tuning target. 3. An automatic tuning device capable of automatically tuning a musical instrument having a plurality of strings and a plurality of string winding knobs for winding the strings, the casing comprising: a casing; and the casing. A motor installed therein, a fitting member that fits into the string winding knob and can transmit a rotational force to the string winding knob, and the casing for transmitting the rotational driving force of the motor to the fitting member A rotary driving force transmission mechanism, a control means for controlling the drive of at least the motor, and a string sound-electrical signal converting means for receiving a string sound and converting the input string sound into an electric signal corresponding to its frequency. And a rotational drive force of the motor is transmitted through the rotational drive force transmission mechanism and the fitting member to the string winding knob fitted to the fitting member to rotate, and to the string winding knob. Winding The control means is configured to adjust the tension of the generated string, and the frequency of the string sound input from the string sound-electrical signal converting means approaches the preset target frequency of the string tuning during tuning. As described above, the automatic string tuning apparatus is controlled so as to drive the motor to change the tension of the strings and to perform the string tuning based on the string sounds generated during the stable period of the string sounds. 4. The automatic tuning device according to claim 3, wherein the control means controls the tuning based on a string tone excluding a string tone generated at least at an initial stage of the string tone generation and at an ending period of the string tone generation. 5. An automatic tuning device capable of automatically tuning a musical instrument having a plurality of strings and a plurality of string winding knobs around which the strings are wound, the casing comprising: a casing; and the casing. A motor installed therein, a fitting member that fits into the string winding knob and can transmit a rotational force to the string winding knob, and the casing for transmitting the rotational driving force of the motor to the fitting member A rotary driving force transmission mechanism, a control means for controlling the drive of at least the motor, and a string sound-electrical signal converting means for receiving a string sound and converting the input string sound into an electric signal corresponding to its frequency. And a tuning precision setting means for setting the tuning precision, wherein the rotary driving force of the motor is fitted to the fitting member via the rotary driving force transmission mechanism and the fitting member. Delivered to the string knob It is configured to adjust the tension of the string wound around the string winding knob, the control means, during tuning, the frequency of the string sound input from the string sound-electrical signal conversion means, in advance, The motor is driven to change the tension of the string so as to approach the set target frequency of the string tuning, and the fitting member is rotated according to the string tuning accuracy set by the string tuning accuracy setting means. An automatic tuning device, characterized in that the speed is controlled to control the tuning. 6. The automatic tuning device according to claim 5, wherein the string tuning accuracy is within a frequency allowable range. 7. An automatic tuning device capable of automatically tuning a musical instrument, which has a plurality of strings and a plurality of string winding knobs around which the strings are wound, and which can be gripped with one hand. A casing, a motor installed in the casing, a fitting member that fits into the string winding knob and can transmit a rotational force to the string winding knob, and transmits a rotational driving force of the motor to the fitting member. For transmitting the rotational driving force, a control means for controlling the drive of at least the motor, and a string sound for converting the input string sound into an electric signal corresponding to the frequency. -Electrical signal converting means, for transmitting the rotation driving force of the motor to the string winding knob fitted to the fitting member via the rotation driving force transmission mechanism and the fitting member to rotate. , The string winding It is configured so that the tension of the string wound around the knob can be adjusted, and the control means, during tuning, the frequency of the string sound input from the string sound-electrical signal converting means is a preset tuning target. An automatic tuning device, characterized in that it operates to drive the motor to change the tension of the string so as to approach the frequency. 8. The fitting member is configured such that a pair of wall portions having curved concave surfaces are arranged such that the curved concave surfaces face each other, and the string winding knob is fitted between the both wall portions. The automatic tuning device according to any one of claims 1 to 7. 9. The automatic stringing device according to claim 8, wherein the fitting member further has a curved concave surface on the inner bottom surface of the fitting member. 10. The control means and the string sound-electrical signal converting means are respectively installed in an automatic stringing device main body separate from the casing, a motor installed in the casing, and the automatic tuning device. The automatic tuning device according to any one of claims 1 to 9, wherein the control means installed in the main body of the string device is configured to communicate by wire or wirelessly.