JP4383272B2 - Fret stringed instrument - Google Patents

Description

  The invention of the present application relates to a structure for correcting the pitch of a stringed instrument having a fret such as a guitar and an auxiliary tool therefor.

  A stringed instrument changes the frequency of a string by changing the length of the string. There are two types of stringed instruments: a plucked instrument that repels and vibrates a string, and a bowed instrument that rubs and vibrates a string. A metal fret embedded at a specific interval is provided on a fingerboard for pressing, and the pitch is changed by changing the length of a string vibrated by the fret. Typical examples of such stringed instruments include guitars and mandrins.

FIG. 1 is a perspective view of a guitar, which is a typical example of a fret stringed musical instrument. More specifically, it is a perspective view of a folk guitar (also called an acoustic guitar) using metal strings.
The front plate 1, the back plate 2, and the side plate 3 have a hollow resonance cylinder 4 and a neck 5 having one end fixed to the resonance cylinder 4. At the other end of the neck 5, a plurality of gear tuners 7 for attaching tension to the string 6 and winding the string are attached. In the case of a guitar, a bridge 8 for fixing the other end of the string is attached to the front plate 1 forming the resonance body 4, and one end of the string 6 is fixed to a hole 9 formed in the bridge 8. ing.

  A fingerboard 11 in which metal frets 10 are embedded at specific intervals is attached to the neck 5. Fixed to one end of the fingerboard 11 is a nut 13 having a plurality of strings 6 aligned at a predetermined interval and provided with grooves 12 for supporting the strings slightly floating above the upper surface of the fret 10. Yes. A saddle 14 is fixed to the bridge 8 for supporting the string 6 slightly above the upper surface of the fret 10 near the other end of the string 6.

FIG. 2 shows a relationship between a string neck and a saddle in a folk guitar.
Six strings are used for the guitar, and the first string 6 ₁ , second string 6 ₂ , third string 6 ₃ , fourth string 6 ₄ , fifth string 6 ₅ , in order from the high-pitched string. It has been referred to as the sixth string _{6 6.} In normal folk guitar, thickness in the first string ₆₁ is 0.30 mm (0.012 ") of thickness in the second string _{6 2} 0.41 mm (0.016" piano wire) each is used, the third string _{6 3} 0.64 mm (0.025 ") of the fourth string _{6 4} 0.81 mm (0.032" in), the fifth string _{6 5} 1.07 mm (0.042 ") of (a, 1.37 mm 0.054) in the sixth string _{6 6",} the windings are used, respectively. The third string 6 _3, fourth string 6 _4, bronze windings wound bronze (bronze) to piano wire is used each for the fifth string 6, _fifth and sixth string 6 _6.

A predetermined scale is obtained by pressing the middle of the string and shortening the length of the vibrating string. The string supported by the nut 13 and the saddle 14 is called an open string and becomes the lowest sound obtained by the string. In a fret instrument such as a guitar, a plurality of frets 10 are arranged from the nut 13 side at a position where the pitch of the fret is increased by a semitone.
Each fret is called a first fret 10 ₁ , a second fret 10 ₂ , a third fret 10 ₃ ... In order from the side closer to the nut 13, and is the twelfth for a sound one octave higher than the open string. The fret 10 ₁₂ is placed at a position intermediate between the nut 13 and the saddle 14.

  By pressing the string 6 against the fingerboard 11 with a finger or the like between the plurality of frets 10, the string 6 is pressed against the fret 10, and the length of the vibrating portion of the string 6 is reduced from the pressed fret 10 to the saddle. By changing the length to 14, the frequency of the string 6 changes.

Here, the pitch of the string of the fret stringed instrument (the natural frequency of the string) will be summarized.
The natural frequency f of the string is inversely proportional to the string length (l), proportional to the square root of the tension (S), inversely proportional to the square root of the unit length weight (γ) of the string, and is expressed by the following equation.
f = (1 / 2l) · (S · g / γ) ^1/2
Here, l: string length, S: tension, γ: string unit length weight, g: gravitational acceleration.
That is, when the tension (S) of the string increases, the sound increases in proportion to the square root, the sound of a thick string with a large square root of unit length weight (γ) decreases, and when the string length (l) changes, The pitch changes in inverse proportion to the length.

In the case of an average rate scale, the ratio of frequencies between semitones is the 12th root of 2 (≈1.05946 or its inverse 0.994388). Accordingly, the first fret 10 _1, nut - is placed in a position of 0.94388 saddle between length L. Similarly, the installation position of the second fret 10 _2, the length of the further .94388 only the strings from the installation position of the first fret 10 ₁ is installed in the shortened position. Repeat this calculation, the installation position of the 12th 12th fret 10 _12, the position of the opening of the chord length of ^(0.94388) 12 = 0.5, i.e., the position of half the length of the open string Placed in.

Table 1 shows a first string ₆₁ is a chord of the highest sound frequency and pitch name of the sound pronunciation sixth string 6 ₆ is a chord of the lowest sound.

In the case of a metal string having high rigidity, when the length of the vibrating string is short, the fixed end of the string is difficult to vibrate, and thus vibrates in a state where the string length is short and the pitch is increased.
For example, the twelfth fret 10 ₁₂ is at the position of the length of the open string of 0.5, and conversely, the saddle 14 only needs to be at a position twice the distance between the nut 13 and the twelfth fret 10 ₁₂ . However, when there hold the strings between placing the saddle 14 and the 11 fret 10 ₁₁ 12th fret 10 _12, the sound obtained is higher than the sound of interest.

  As mentioned before, the folk guitar has a piano wire of 0.30 mm for the first string, 0.41 mm for the second string, 0.64 mm for the third string, and 0.4 for the fourth string. Bronze-wound piano wires of 81 mm, 1.07 mm for the fifth string and 1.37 mm for the sixth string are used, each having a different stiffness. Therefore, the relationship between the sound obtained by the open string defined by the nut and the sound one octave above defined by the 12th fret differs for each string, and when the string is thick, the fixed end of the string is difficult to vibrate. For this reason, it vibrates in a state where the chord length is shortened, and the degree of pitch rise is large.

Therefore, when a folk guitar, as shown in FIG. 2, the period from the treble side thin first string ₆₁ to the sixth string 6 ₆ thick with bass side, away the position of the saddle 14 from the nut 13, the saddle 14 is a nut 13 Are arranged slightly diagonally rather than in parallel.
For example, in the case of a folk guitar with a string length of 648 mm used for mathematically determining the position of the fret 10, the position where the string length on the center line is about 2.8 mm and both ends of the saddle are about 5.6 mm longer. There is a saddle 14 installed.

The relationship between the fingerboard, nut, fret and string will be described with reference to FIG.
In this figure, the neck 5 is viewed from the side, and a nut 13 and frets 10 ₁ , 10 ₂ , 10 ₃ ... Are arranged at predetermined positions on the neck 5, and a groove 12 formed in the nut 13 and A string 6 is stretched between a saddle (not shown).
The nut 13 is often called a zero fret because it determines the pitch of the open string.

Since the performance is easier when the distance required to hold down the strings is smaller, the distance between the strings and the frets is made as small as possible.
The swing width of the string near the nut 13 which is the fixed end of the string is small, but the swing width of the string near the center portion of the string far from the nut and the saddle 14 which is the fixed end is large. Therefore, the distance between the first fret 10 ₁ and the chord 6 close to the nut 13 is small, the interval between the 12th fret 10 ₁₂ and chord 6 away from the nut 13 is increased.
Since the thick strings tends to chatter occurs against the frets than thin strings, the interval between the sixth string 6 ₆ and fret 10 is larger than the first string _61, the six-string side of the saddle to the first It is formed higher than the string side saddle.
This relationship is shown in Table 2.

FIG. 4 shows the state of the strings when playing the guitar.
As shown in (a), when the string 6 with a finger 22 between the fourth fret 10 ₄ fifth fret 10 ₅ pressed against the fingerboard 11, the strings 6 becomes slightly stretched state. For this reason, the tension of the string is slightly increased. The pitch (frequency) of the sound emitted by the strings is proportional to the square root of the string tension. Therefore, in this case as shown, more slightly higher sound fifth fret 10 sounds on 4 degrees from open string to be obtained by ₅ is obtained.

  Such a slight pitch deviation is ignored as it does not affect the audibility in a fret stringed instrument such as a guitar that presupposes an average temperament that divides one octave into 12 semitones at equal intervals.

Usually, as described above, the fret 10 is installed in parallel with the nut 13 which is one of the fixed ends of vibration of the string 6 at the calculated position.
As shown in FIG. 2, in a folk guitar using a metal string, the saddle 14 forming the other fixed end of the vibration of the string 6 is arranged slightly obliquely with respect to the fret 10. .

As described above, installed is a position of the 12th 12th fret 10 ₁₂ Since placed 1/2 position of the length of the open string, a position where the saddle 14 is placed, the first nut 13 12 Although it would be twice the position of the distance to the fret 10 _12, placing the saddle 14 there, for the described phenomenon, when playing pressing the fret 10, a higher sound than the sound desired can get.

Therefore, since the chord thickness from the first string 6 ₁ treble side to the sixth string 6 ₆ gradually thicker, away the position of the saddle 14 from the nut 13 in accordance becomes thicker strings, as the chord length increases It is necessary to install, so that the saddle is arranged slightly diagonally.

  For example, in the case of a folk guitar having a reference scale length of 648 mm, which is the chord length used when calculating the position of the fret 10, the saddle 14 is installed at a position where the chord length is about 2.8 mm longer on the center line. .

Meanwhile, as shown in (b), when pressing the strings 6 between nut 13 and the first fret 10 ₁ in order to obtain a semitone higher sound than the sound obtained by the open string is the string tension S The increase is large. For this reason, the sound obtained from the first fret has a height that cannot be ignored in terms of hearing than the sound that should originally be obtained. This increase in string tension is greater for thick strings with greater stiffness.

Thus, when pressed strongly strings 6 on the finger plate 11 by the finger 22 between the nut 13 and the first fret 10 _1, the string 6 is stretched significantly, the string tension is greatly increased. Therefore, it becomes much higher pitch than the pitch of a sound obtained by the calculation by the first fret 10 ₁ position.

This phenomenon, for example, in the case the thickest 0.054 "of the sixth string _{6 6} (1.37 mm) bronze winding, the correct 30 to relative pitch 40 cents (1 cent to expected average of temperament A pitch obtained by dividing a semitone into 100 equal parts).

For example, even in the case of a classic guitar using a gut string, the distance from the nut to the first fret is corrected by 1.1 to 1.7% shorter than the calculated value.
In current folk guitars and electric guitars that use metal strings, there is a great need for correction because the string tension is high.

Japanese translations of PCT publication No. 2002-508087 (Patent Document 3) (see US Pat. No. 5,955,689), US Pat. No. 5,404,783 (Patent Document 5) and US Pat. No. 5,814,745 No. (Patent Document 6) shows that the distance between the nut and the first fret is in the range of 1% to 10% shorter than the standard value.
Further, JP 2002-508087 A (Patent Document 3) (see US Pat. No. 5,955,689) specifically describes 3.3% in the case of nylon strings and 1. in the case of steel strings. 4%, and 2.1% for electric guitars and electric basses.

Further, in the normal folk guitar as already mentioned first string ₆₁ and the second string _{6 2,} piano wire is used, the third string _{6 3,} fourth string _{6 4,} fifth string ₆ 5, bronze winding bronze (bronze) is wound piano wire to the sixth string 6 ₆ has been used.
In addition, strings of various thicknesses (called gauges) are used as metal strings, including electric guitars and electric basses.

  If the string material / structure and thickness are different, the correct saddle position and the nut position, which is the other end of the string, must be corrected for each fret. The optimum amount changes.

In such a case, as an example, it is possible to correct the nut position for each string in US Pat. No. 6,156,962 (Patent Document 2) and US Pat. No. 6,433,264 ( Patent Document 1).
In order to make this phenomenon as small as possible, the position of the nut is arranged close to the first fret, or the position from the nut is set in steps corresponding to the distance to the first fret. Nuts are used.

US Pat. No. 6,433,264 (Patent Document 1) illustrates a nut 15 having the shape shown in FIG. Nut 15 secured to the nut groove 16 is located a position for supporting the respective strings are changing every chord, the support position 17 ₆ of the sixth string 6 ₆ lowest sound farthest from the first fret 10 ₁ supporting grooves 12 ₆ of the nut 15 is formed so as to, the nut 15 as the support position 17 ₁ of the first string ₆ of _the highest sound is closest to the first fret 10 _first support grooves 12 ₁ Is formed.

Such shape gap between the nut support position 17 ₆ in the sixth string _{6 6} and the first fret 10 ₁ becomes smaller than the distance between the nut support position 17 ₁ and the first fret 10 ₁ in the first string _{6 1} ing.
However, since the structure of the nut 15 is complicated, it takes time for processing.

US Pat. No. 6,156,962 (Patent Document 2) shows a nut having the shape shown in FIG. The nut 18 which is secured sixth string 6 ₆ side width wide in the nut groove 19, the first string ₆₁ side to narrow width, i.e. are formed in wedge, and the support grooves 12 for supporting the strings are formed on the upper surface Yes.

Such spacing of the sixth string _{6 6} nut 18 in the first fret 10 ₁ by the shape is smaller than the distance between the nut 18 and the first fret 10 ₁ in the first string _{6 1.}
However, since the mounting surface of the nut 18 is not rectangular, the nut 18 cannot be mounted instead of a normal nut having a rectangular shape.
In addition, when the correction amount varies due to the change in the thickness of the string used, it cannot be replaced with a nut of another shape.

FIG. 7 shows a bridge 8 and a conventional saddle 14. The saddle 14 is inserted into a saddle groove 71 provided obliquely on the bridge 8. In the case of such a saddle 14, but the first string 6 ₁ and sixth-string 6 ₆ at both ends of the saddle 14 can be matched precisely to the desired chord length, forced to become an approximate value for the other strings I don't get it.
Usually, the saddle 14 is installed at a position where the pitch when the _twelfth twelfth fret 10112 is played is correctly higher than the pitch of the open string by one octave.

Conventional saddle 20 shown in FIG. 8, the chord rests of the position of the upper surface is formed by cutting the side surface of the saddle 20 diagonally, the pitch when the play pressing the 12th 12th fret 10 ₁₂ , adjusted to correct one octave higher such positions than pitch of the open string saddle upper surface _{20 1,} 20 _{2, 20} 3, 20 _4, 20 5, 20 ₆ are formed, saddle grooves 21 provided obliquely to the bridge 8 Is plugged into.
In the case of this example, when the thickness of the string to be used is changed, it is necessary to replace the saddle 20 with another one so that the position of the upper surface of the saddle becomes an optimum position that matches the characteristics of the string.

  The saddle 14 shown in FIG. 2 is configured as a single body, but in addition to this, US Pat. No. 5,955,689 (Japanese Patent Publication No. 2002-508087) discloses a first string and a second string. 2 saddles for the 3rd to 6th strings, and for the 1st and 2nd strings, 3rd and 4th strings, 5th string A saddle for the first and sixth strings and three saddles, and a total of six saddles for each string are shown.

  Also, there are shown saddle position adjusting / fixing means that do not use any special means, those that adjust / fix by an adjusting screw mechanism, and those that further fix the adjusting screw with a screw.

  FIG. 9 shows an example of divided saddles in a folk guitar. A saddle block 27 having a flat bottom surface and a ridge-like projection is disposed on the flat portion 26 of the bridge 8. The saddle block 27 has a length on which two adjacent strings 6 are placed. Therefore, in the case of a 6-string folk guitar, three saddle blocks 27 are arranged.

  Ordinary folk guitars are played with the sound emitted from the resonance drum 4 when a string is played, but many electric guitars that are electrically connected to an acoustic loudspeaker (amplifier) and play at a high volume are also used. Yes. In this case, as shown in FIG. 10, a piezoelectric element such as a piezo pickup 90 that extracts the vibration of the string as an electric signal is incorporated in the saddle portion.

  As shown to (a), the piezo pick-up 90 is installed in the saddle groove | channel 71 carved diagonally in the bridge | bridging 8, and the saddle 14 is mounted on it. The piezo pickup 90 installed in this way is usually called an under saddle pickup.

  A sectional view of the undersaddle pickup attached is shown in FIG. A piezo pickup 90 is installed on the bottom of a saddle groove 71 provided in a bridge 8 attached to the guitar front plate 1 by bonding or the like, and the saddle 14 is placed thereon. One end of the string 6 is fixed in a hole 9 formed in the bridge 8 and is stretched on the saddle 14. When the string vibrates, the vibration propagates through the saddle 14 to the piezo pickup 90, and generates an electrical signal. The electric signal is transmitted to the sound loudspeaker (amplifier) via the lead wire 91.

US Pat. No. 6,433,264 US Pat. No. 6,156,962 Japanese translation of PCT publication No. 2002-508087 US Pat. No. 5,955,689 US Pat. No. 5,404,783 US Pat. No. 5,814,745

  In this application, a nut, a nut auxiliary tool, and a saddle that can be easily readjusted so that the correct pitch can be obtained without adding new processing to the guitar body even when the strings used are changed. Provide a piece.

  The nut or the nut assisting tool according to the present application has a pitch obtained by pressing the first fret by optimizing the interval between the nut or the nut assisting tool and the first fret, Try to be exactly one semitone above.

  By optimizing the distance between the saddle piece and the twelfth fret according to the present application, the pitch obtained by pressing the twelfth fret is exactly one octave above the pitch produced by the open string. To do.

  Furthermore, by optimizing the distance between the saddle piece saddle piece and the 12th fret when using the nut or the nut auxiliary tool according to the present application, the pitch obtained by pressing the 12th fret is pronounced by the open string. Make it exactly one octave above the pitch being played.

  By comprising in this way, the rise of the pitch of the 1st fret and the 12th fret which remarkably raises the pitch by the influence of the height difference of the string used and the open string and the fret is alleviated.

Examples will be described below.
The first embodiment is for an integrated nut and nut assist.
A nut 21 and a nut 24 shown in FIG. 11 are improved versions of the conventional nut shown in FIG.
The nut 21 is provided with a mounting portion 23 having the same shape as the conventional nut mounting portion to be attached to the nut mounting portion 25 of the finger plate 11 or the neck 5 below the nut 18 of FIG. the the width wide sixth string 6 ₆ side, the first string 6 ₁ side narrow width, that is, formed on the wedge, the support grooves 12 for supporting the strings on the top surface is formed.
Further, the specific shape includes a nut 21 simply provided with a mounting portion 23 as shown in (a) and a nut 24 further provided with an extension portion 26 as shown in (b).
Further, the widths of the upper surfaces of the nut 21 and the nut 24 may be formed narrow and constant.

(C) shows a form in which the nut 24 shown in (b) is attached to the guitar.
A nut 24 is attached to the end portion 27 of the fingerboard 11 in place of the conventional nut.
The nut 21 and nut 24 shown in this embodiment can be easily replaced with a conventional nut because the mounting portion 23 has the same shape as the conventional nut mounting portion.

The nut 21 shown in (a) has a simple shape, and the nut 24 shown in (b) has a feature that it is stable when attached to a guitar.
The nut 21 can be easily replaced with a conventional nut, and the shape is simple, so that it is easy to make.

Such spacing of the sixth string _{6 6} nut 18 in the first fret 10 ₁ by the shape is smaller than the distance between the nut 18 and the first fret 10 ₁ in the first string _{6 1.}

FIG. 12 shows a nut whose mounting position is adjusted.
This nut 36 is substantially the same structure as conventional nut, a long hole 37 for screwing has at both ends of the first string ₆₁ side and the sixth string 6 ₆ side, screw the long hole the position stop 38 attached obliquely at an optimum angle of the nut 36 relative to the first fret 10 _1.

A nut used instead of a conventional nut will be described with reference to FIGS. 13 and 14.
The nut 61 shown in FIG. 13 is a single string nut configured separately for each string. A long hole 62 is formed in the single string nut 61 and is fixed to the nut mounting portion 64 of the neck 5 by a set screw 63.

The nut shown in FIG. 14 is a dual string nut 65 on which two strings are placed, and a long hole 66 formed in the base portion is fixed to the nut attaching portion 64 of the neck 5 by a set screw 67.
It goes without saying that the single nut and dual string nut shapes shown in FIGS. 13 and 14 can be changed from each other.

The integrated nut assisting tool will be described with reference to FIG.
The nut auxiliary tool 31 shown in (a) can be used on the fingerboard by lowering the back of the nut shown in FIG.
The nut auxiliary tool 32 shown in (b) has the upper surface 33 whose width is thin and constant.
The nut auxiliary tool 32 can be formed by scraping off both sides of a prism.
Since the fingerboard of a normal folk guitar has a slight curvature to make it easier to hold down the strings, the upper surface 33 may be provided with a curve that matches the curvature.

The form which attached the nut auxiliary tool 31 to the guitar is shown to (a).
A nut auxiliary tool 31 is mounted adjacent to the nut 13 mounted on the fingerboard 11.
Since the nut auxiliary tool 31 may be simply placed without replacing the nut, it is easy to deal with even when the conditions change.

FIG. 16 shows another example of the nut auxiliary tool.
The nut auxiliary tool 34 shown in (a) has a shape obtained by dividing the truncated cone 35 shown in (b) in the axial direction so that the height is appropriate.
The form which mounted | wore the guitar with the nut auxiliary tool 34 shown to (b) is shown to (a).
A nut auxiliary tool 34 is mounted adjacent to the nut 13 mounted on the fingerboard 11.

In addition to the truncated cone, this shape may be a shape obtained by dividing a truncated pyramid such as a triangular truncated pyramid or a quadrangular truncated pyramid in the axial direction.
Since the fingerboard of a normal folk guitar has a slight curvature to make it easier to hold down the strings, the shape of the truncated cone or the truncated pyramid can be matched to the curvature.
Further, as shown in (c), a support groove 12 for string support is formed on a string support surface parallel to the finger plate of the nut auxiliary tool 39 which is a trapezoidal flat plate, and a recess 40 for adjusting the support position is further formed. It is formed.
The nut assisting tool 34 is not only easy to manufacture, but a plurality of nut assisting tools 34 can be manufactured simultaneously.

As shown in FIG. 17, the three nut auxiliary tools 41 ₁ , 41 ₂ , and 41 ₃ may be connected by a metal wire 44 such as a mild steel wire that can be freely bent. By doing so, even when the string is removed and replaced, the positional relationship of the nut auxiliary tools 41 ₁ , 41 ₂ , and 41 ₃ once set can be maintained as it is, so that readjustment is unnecessary. The three nut auxiliary tools 41 ₁ , 41 ₂ , and 41 ₃ can be easily readjusted by bending the mild steel wire 44 even when the thickness of the strings to be used changes and the position needs to be readjusted. Is possible.

FIG. 18 shows an example of a nut auxiliary tool divided into guitars.
In this example, as shown in (a) and (b), three metal nut auxiliary tools 41 ₁ , 41 ₂ , 41 ₃ are arranged at predetermined positions near the nut 13. In the conventional nut 13, a plurality of strings 6 are aligned at a predetermined interval at one end of the fingerboard 11, and a groove 12 is provided to support the strings slightly floating above the upper surface of the fret 10. In the case of the example, the groove 12 has only the function of aligning the plurality of strings 6 at a predetermined interval, does not have the function of floating and supporting the strings 6, and the strings are slightly above the upper surface of the fret 10. Nut auxiliary tools 41 ₁ , 41 ₂ , 41 ₃ have the function of floating and supporting the strings.

The length of the nut auxiliary tools 41 ₁ , 41 ₂ , 41 _{3 is} a length on which two adjacent strings 6 are placed. Therefore, in the case of a 6-string folk guitar, three nut auxiliary tools 41 ₁ , 41 ₂ , 41 ₃ are used.
The diameters of the nut auxiliary tools 41 ₁ , 41 ₂ , 41 ₃ are slightly larger than the height of the fret 10 in order to support the string 6 by slightly lifting the string from the upper surface of the fret 10.

For normal folk guitar, the spacing of the strings 6 and fret 10, a first string ₆₁ side is small, increasing the sixth string 6 ₆ side is generally performed.
Accordingly, the diameters of the nut auxiliary tools 41 are not all the same, and are set to optimum values depending on the strings used.
The nut auxiliary tools 41 ₁ , 41 ₂ , and 41 ₃ may have a conical shape that is slightly thick at one end, in addition to the cylindrical shape.

In order to support the string 6 with the string slightly lifted from the upper surface of the fret 10, the nut auxiliary tools 41 ₁ , 41 ₂ , 41 ₃ are flat as shown in (c) so as to be stably supported on the fingerboard 11. A half-round bar 43 having a part 42 is used.

The tuning method in the example of FIG. 18 will be described with reference to FIG. This figure shows a cross-sectional view of a state in which the string 6 is stretched between the nut 13 and the nut auxiliary tools 41 ₁ , 41 ₂ , 41 ₃ . In the conventional example, as described above, installed is a position of the first fret 10 _1, which had been installed at 0.94388 times the position of the length of the open string, the case of this example one of the open strings Since the parts supporting the ends of the nuts are not the nut 13 but the nut auxiliary tools 41 ₁ , 41 ₂ , 41 ₃ , the nut auxiliary tools 41 ₁ , 41 ₂ are determined from the distance from the conventional nut 13 to the first fret 10 _1. , 41 ₃ to the first fret 10 ₁ is set to a short value.

Release finger 22 and repel open string. Pitch at this time, exactly a semitone only lower position than the pitch at the time of pressing between the nut aid 41 of the first fret 10 _1, to move the nut aid 41.

The regulation described above is repeated from the first string ₆₁ Sixth string _{6 6.}
The first string ₆₁ and the second string 6 ₂ is used piano wire, since the direction of the second string 6 ₂ are slightly a thick strings used than the first string _61, the nut aid 41 ₁ It is adjusted to a slightly tilted state.

By string 6 is pressed between the nut aid 41 of the first fret 10 ₁ by the finger 22, pitch defined by the first fret 10 ₁ is pronounced. As described in the conventional example, when pressing the strings, but the string tension is increased slightly, while in the case of, you press between the nut aid 41 of the first fret 10 ₁ embodiment, the interval of 1 fret 10 ₁ to adjust the tension of the string 6 so as to have a predetermined pitch. Thus, the sound of the first fret 10 ₁ is always correct pitch is obtained.

  The position of the nut auxiliary tool 41 is fixed on the fingerboard 11 by the pressure of the string 6. In the state where the string 6 has a predetermined tension, the position of the nut auxiliary tool 41 does not shift, but when the tension of the string 6 is loosened or the string 6 is removed, the position shifts. . In that case, after performing the series of adjustments described above, it may be fixed with an adhesive or the like.

  The tuning method in the embodiment of FIG. 9 will be described with reference to FIG. One end of the string 6 is fixed in the hole 9 formed in the bridge 8, is placed on the saddle block 76, stretched along the fingerboard 11 in which the fret 10 is embedded, and the end of the fingerboard 11 Is mounted on the nut auxiliary tool 41, guided by the groove 12 provided in the nut 13, and wound up by the gear tuner 7.

The saddle block 76 is not fixed and can move in the longitudinal direction of the string. The first string ₆₁ and the saddle block 76 ₁ which rests the second string 6 _2, the pitch when played pressing the 12th 12th fret each string, correctly octave higher than the pitch of the open string Install in such a position. The other saddle blocks 76 ₂ and 76 ₃ are arranged by performing the same adjustment.

  By using such a divided saddle block 76, even when the thickness of the string to be used is changed, the optimum tuning can be easily performed without changing parts by readjusting the position. Become.

  The position of the saddle block 76 is fixed on the bridge 8 by the pressure of the string 6. In a state where the string 6 has a predetermined tension, the position of the saddle block 76 does not shift, but when the tension of the string 6 is loosened or the string 6 is removed, the position shifts. In that case, after performing the series of adjustments described above, it may be fixed with an adhesive or the like.

  Instead of the mild steel wire 44, a thin plate 46 having a connecting portion 45 may be used as shown in FIG.

  22 shows that hooks 47 are provided at both ends of the connecting portion 45 of the three nut auxiliary tools 41 connected by the thin plate 46 having the connecting portion 45 shown in FIG. 21, and the hook 47 is fitted into the nut 13. And it can be fixed.

  Instead of the hook 47, it is also possible to form embedded members 48 at both ends of the connecting member 45 as shown in FIG. 23, and to embed the embedded members 48 in the nut 13 and fix them by means such as adhesion. Although the front end of the embedding member 48 shown in this figure is bent, the front end is not bent when the nut 13 is a material that is not a moldable material such as plastic, for example, animal bone.

In the example shown in FIG. 24, a thin plate 50 in which a long hole 49 is formed is fixed to the nut auxiliary tool 41, and the position is adjusted and fixed by a screw 51 in the long hole 49.
When the thickness of the string to be used changes and it is necessary to readjust the position, the position of the nut auxiliary tool 41 is readjusted with the screw 51 using the long hole 49.

  A strip piece 54 provided with a fixing piece 53 in which a long hole 52 is formed is fixed to the nut auxiliary tool 41 shown in FIG. Adjustment of the position of the nut auxiliary tool 41 is performed in the same manner as the case shown in FIG.

26 shows that the strips 55 and 56 are fixed to the nut auxiliary tool 41, and the strips 55 and 56 are provided with a fixing portion 57, and the fixing portion 57 has a hole.
With this configuration, even when all the strings are removed, the position of the nut auxiliary tool 41 once set can be maintained as it is, so that readjustment is unnecessary.

In the case of the folk guitar shown in FIG. 26, since the neck 5 is warped by the tension of the string, a truss rod that has a screw structure at the end in the neck 5 and can be bent by rotating the screw; The metal rod called is embedded. The truss rod is arranged so that its screw portion appears in the immediate vicinity of the nut 13, and the screw portion of the truss rod is usually covered by a rod cover 58. The rod cover 58 is fixed by set screws 59 and 60.
The fixing portion 57 of the strip 55 in this example is fixed to the neck 5 by set screws 59 and 60 for fixing the rod cover 58.

  The nut for the fret stringed instrument shown in FIGS. 12, 21, and 14 and the fret stringed instrument shown in FIGS. 15, 16, 17, 21, 22, 22, 23, 24, 25, and 26. The nut assisting tool is one in which all strings are placed, two strings are placed, or one string is placed, but the form is not limited to these, Needless to say, the number of strings to be placed can be arbitrarily set.

  Moreover, although the embodiment shown so far is a replacement part of an existing nut or an auxiliary tool used in addition to the existing nut, it is attached to a fret string instrument from the beginning as a nut or as an auxiliary tool attached to the nut. It can also be done.

Next, a saddle that can adjust the pitch of each string more accurately will be described by taking a folk guitar using a nut and a nut auxiliary tool as an example.
FIG. 27 shows an example of a saddle block.

  The height of the saddle block 76 is sufficiently high to support the string 6 by slightly lifting the string from the upper surface of the fret 10, and uses an object having an optimum height according to the thickness of the string to be used. . The saddle block 76 may be made of a plastic molded product, an animal bone, or made of metal.

  As shown to (a), the small hole 77 is made in each saddle block 76, and metal wires 78, such as a mild steel wire, are inserted. For this purpose, a structure in which the saddle block 76 and the mild steel wire 78 are bonded with an adhesive or the like may be used.

  As shown in (b), the other end of the mild steel wire 78 is held through a bridge block 81 having a slide hole 80 through which the mild steel wire 78 passes. The bridge block 81 is fixed to the existing bridge 8 with a small screw 82. The bridge block 81 is provided with a screw hole 83 at a position corresponding to the slide hole 80, and the position can be fixed by tightening the mild steel wire 78 passed through the slide hole 80 with a screw 84. Thereby, if the screw 84 is tightened, the position of the saddle block 76 attached to the tip of the mild steel wire 78 is maintained.

A tuning method in the embodiment of FIG. 27 will be described.
In a state where the screw 84 is loosened, the saddle block 76 is not fixed, and can move in the longitudinal direction of the string. The first string ₆₁ and the saddle block 76 ₁ which rests the second string 6 _2, the pitch when played pressing the 12th 12th fret each string, correctly octave higher than the pitch of the open string The mild steel wire 78 is bent and installed at such a position, and the screw 84 is tightened in that state. The other saddle blocks 76 ₂ and 76 ₃ are arranged by performing the same adjustment.

Since the second string 6 ₂ is thick strings are used than in the first string _61, the saddle block ₇₆₁ which rests the those two strings is positioned slightly tilted. If the mild steel wire 78 is bent in accordance with this inclination, the position of the saddle block 76 will not be displaced even when the strings are loosened or removed.

FIG. 28 shows another embodiment.
In order to mount each string 6 individually, an individual saddle piece 85 is arranged. The cross-sectional shape of the saddle piece 85 may be an elliptical shape having a flat portion 86 on the bottom surface as shown in (a), or a round shape as shown in (b). A small hole 77 is formed in the longitudinal direction of the saddle piece 85.
The saddle piece 85 may be made of a plastic molded product, an animal bone, or made of metal.

  A metal wire 87 such as a mild steel wire whose tip is bent at a right angle is inserted into the small hole 77 of the saddle piece 85. The other end of the mild steel wire 87 is held through a bridge block 81 in which a slide hole 80 through which the mild steel wire 87 passes is formed. The bridge block 81 is fixed to the existing bridge 8 with a small screw 82. The bridge block 81 is provided with a screw hole 83 at a position corresponding to the slide hole 80, and the position can be fixed by tightening a mild steel wire 87 passed through the slide hole 80 with a screw 84. Thereby, if the screw 84 is tightened, the position of the saddle piece 85 attached to the tip of the mild steel wire 87 is maintained. Therefore, even when the string is loosened or removed, the position of the saddle piece 85 is not displaced.

A tuning method in the embodiment shown in FIG. 28 will be described.
When the screw 84 is loosened, the saddle piece 85 is not fixed and can move in the longitudinal direction of the string. The first string ₆₁ of the saddle piece 85 rests, pitch when played pressing the 12th 12th fret, installed correctly octave higher becomes such a position from the pitch of the open string, in that state Screw 84 is tightened. The other saddle pieces are arranged and fixed with the same adjustment.

  The bridge block 81 shown in FIGS. 27 and 28 may be made of the same wood as that of the bridge 8, or may be a molded product made of plastic. Since the bridge block 81 is made of such a light material, even if it is additionally attached to the bridge 8 of the existing folk guitar, the tone of the folk guitar is not impaired. The bridge block 81 may be formed integrally with the bridge 8.

FIG. 29 shows an embodiment in which the saddle block 76 and the saddle piece 85 shown in the above embodiment are used together with an under saddle pickup.
A saddle piece 85 on which the string 6 is placed as shown in FIG. 5A is placed on a saddle extension 92 placed in a saddle groove 71 formed in the bridge 8 with a part of the bottom surface placed thereon. A piezo pickup 90 is placed on the bottom of the saddle groove 71, and a saddle extension 92 is placed thereon. The saddle extension 92 has a height slightly protruding from the upper surface of the bridge 8. The saddle extension 92 may be made of a plastic molded product, or by cutting animal bones, wood or metal.

  An example of the shape of the saddle piece 85 is shown in FIG. A part of the saddle piece 85 guides a block portion 93 having a small hole 77 for inserting a bent portion of a mild steel wire 87 whose end portion is bent at a right angle, a top portion 94 on which the string 6 is placed, and the string 6. A guide portion 96 having an inclined surface 95 is integrally formed. The saddle piece 85 may be made by molding a plastic molded product, or by shaving animal bones or metal.

  The other end of the mild steel wire 87 is held through a bridge block 81 in which a slide hole 80 through which the mild steel wire 87 passes is formed. The bridge block 81 is fixed to the existing bridge 8 with a small screw 82. The bridge block 81 is provided with a screw hole 83 at a position corresponding to the slide hole 80, and the position can be fixed by tightening a mild steel wire 87 passed through the slide hole 80 with a screw 84. Thereby, if the screw 84 is tightened, the position of the saddle piece 85 attached to the tip of the mild steel wire 87 is maintained. Therefore, even when the string is loosened or removed, the position of the saddle piece 85 is not displaced.

FIG. 30 shows a cross-sectional view of the guide portion 96 of the saddle piece 85 of the present embodiment.
As shown in (a), one end of the string 6 is fixed in the hole 9 formed in the bridge 8 and is placed on the guide portion 96 of the saddle piece 85, and the fingerboard 11 in which the fret 10 is embedded. Is placed on the nut auxiliary tool 41 disposed at the end of the fingerboard 11, guided by the groove 12 provided in the nut 13 and wound up by the gear tuner 7, and a predetermined tension is generated in the string 6.

  Since the saddle piece 85 is partly placed on the saddle extension 92 placed in the saddle groove 71 carved in the bridge 8, when a predetermined tension is generated on the string 6, The fulcrum portion 97 at one end of the saddle piece 85 is pressed against the upper surface of the bridge 8. When the string 6 vibrates in this state, the force acts on the top portion 94 of the guide portion 96 of the saddle piece 85, and an action point 98 that is a contact point between the saddle piece 85 and the saddle extension 92 according to the so-called “lever principle”. The vibration force of the string 6 acts on the.

  Thus, the vibration of the string 6 is transmitted to the contact point of the saddle extension 92, propagates through the saddle extension 92, is transmitted to the piezo pickup 90, and generates an electrical signal. The electric signal is transmitted to the sound loudspeaker (amplifier) via the lead wire 91.

  In order to effectively transmit the vibration force of the string 6 to the piezo pickup 90, the fulcrum portion 97 at one end of the saddle piece 85 mounted on the bridge 8 is in contact with the action point 98 that is the contact point of the saddle extension 92. The end of the saddle piece 85 opposite to the top 94 of the guide portion 96 is desirable.

  An embodiment for clarifying the contact point between the string 6 and the saddle piece 85 and more effectively transmitting the vibration force of the string 6 to the piezo pickup 90 is shown in FIG. It is also effective to provide a recessed portion 99 in a part of the slope 95 of the guide portion 96 of the saddle piece 85. In the saddle piece 85 having such a shape, the vibration force of the top portion 94 of the guide portion 96 of the saddle piece 85 is a contact point of the saddle extension 92 with the fulcrum portion 97 at one end of the saddle piece 85 as a fulcrum. It can be transmitted to the action point 98.

  The inclined surface 95 of the guide portion 96 of the saddle piece 85 may have a string groove 100 that prevents the string 6 from shifting laterally as shown in FIG.

A tuning method in the example of FIG. 30 will be described.
In a state where the screw 84 is loosened, the saddle piece 85 is not fixed, and has a structure that can move in the longitudinal direction of the string. The saddle piece 85 ₁ resting the first string _61, pitch when played by pressing the 12th 12th fret, installed correctly octave higher such positions than pitch of the open string, the condition Tighten the screws 84 with. Place the other saddle pieces with the same adjustment.

  The shape of the embodiment of the saddle piece 85 shown in FIG. 30B can be used even when the under saddle pickup is not used. In that case, the bottom surface of the saddle piece 85 is placed directly on the top surface of the bridge 8.

FIG. 31 shows another embodiment of the T-shaped saddle piece 101.
As shown in (a), a small hole 77 is made in the T-shaped saddle piece 101, and a metal wire 78 such as a mild steel wire is inserted. For this purpose, a T-type saddle piece 101 and a mild steel wire 78 bonded with an adhesive or the like may be used. A guide portion 96 having a top portion 94 on which the string 6 is mounted and a slope 95 for guiding the string 6 is integrally formed on both sides of the T-shaped saddle piece 101. The T-shaped saddle piece 101 may be made by molding a plastic product, or by cutting animal bones or metal.

  (B) shows the attachment state of the T-shaped saddle piece 101 of the present embodiment. The guide portions 96 on both sides of one saddle piece 85 each carry one string. Therefore, in this embodiment, three T-shaped saddle pieces 101 are arranged.

  As shown in (b), the other end of the mild steel wire 78 is held through a bridge block 81 having a slide hole 80 through which the mild steel wire 78 passes. The bridge block 81 is fixed to the existing bridge 8 with a small screw 82. The bridge block 81 is provided with a screw hole 83 at a position corresponding to the slide hole 80, and the position can be fixed by tightening the mild steel wire 78 passed through the slide hole 80 with a screw 84. Thereby, if the screw 84 is tightened, the position of the T-shaped saddle piece 101 attached to the tip of the mild steel wire 78 is maintained.

A tuning method in the example of FIG. 31 will be described. In the state where the screw 84 is loosened, the T-shaped saddle piece 101 is not fixed and has a structure that can move in the longitudinal direction of the string. The first string ₆₁ and the second string 6 T-shaped saddle piece 101 ₁ resting of _2, the pitch when played pressing the 12th 12th fret each string, correctly than pitch of the open string 1 The mild steel wire 78 is bent and installed at a position where the octave becomes higher, and the screw 84 is tightened in this state. The other T-shaped saddle pieces 101 ₂ and 101 ₁ are also arranged with the same adjustment.

Since the second string 6 ₂ is thick strings are used than in the first string _61, those two T-shaped saddle piece 101 ₁ resting of strings is positioned slightly tilted. If the mild steel wire 78 is bent in accordance with this inclination, the position of the T-shaped saddle piece 101 will not shift even when the string is loosened or removed.

  29, the T-shaped saddle piece 101 of the present embodiment is placed on a saddle extension 92 placed in a saddle groove 71 carved in the bridge 8 with a part of the bottom surface placed thereon. Therefore, when a predetermined tension is generated in the string 6, the fulcrum portion 97 at one end of the T-shaped saddle piece 101 is pressed against the upper surface of the bridge 8. When the string 6 vibrates in this state, the force acts on the top portion 94 of the guide portion 96 of the T-shaped saddle piece 101, and at the contact point between the T-shaped saddle piece 101 and the saddle extension 92 by the so-called “lion principle”. The vibration force of the string 6 acts on a certain point of action 98.

  The shape of the saddle piece 85 shown in FIG. 29B and the embodiment of the T-shaped saddle piece 101 shown in FIG. 31B can be used even when the under saddle pickup is not used. In that case, the bottom surface of the saddle piece 85 and the bottom surface of the T-shaped saddle piece 101 are placed directly on the top surface of the bridge 8.

  The height of the saddle block 76 is sufficiently high to support the string 6 by slightly lifting the string from the upper surface of the fret 10, and uses an object having an optimum height according to the thickness of the string to be used. . The saddle block 76 may be made of a plastic molded product, an animal bone, or made of metal.

FIG. 32 shows another embodiment of the adjusting mechanism for the saddle piece 85.
In the case of this embodiment, in order to hold the position of the saddle piece 85, a bridge pin 102 for fixing one end of a string of a normal acoustic guitar is used.

(B) shows the structure of the bridge pin 102.
The bridge pin 102 has a tapered portion 103 for fixing one end of the string 6 by being inserted into the hole 9 of the bridge 8 and a head portion 104. A slot 105 through which a string passes is formed in the taper portion 103. One end of the string 6 is fixed in a state where the string 6 is passed through the slot 105 and the tapered portion 103 is inserted into the hole 9 of the bridge 8.

  The head 103 is usually formed in a spherical shape and has a function for holding the bridge pin 102 when it is pulled out. The bridge pin 102 is made of a plastic molded product, a material obtained by cutting an animal bone, wood such as ebony, or metal.

  In the case of the embodiment shown in (b), a slide hole 80 through which the mild steel wire 87 is passed is formed on the side surface of the head 103 in the longitudinal direction of the string 6. A screw hole 83 for fixing the mild steel wire 87 is formed at the top of the head 103.

  On the upper surface of the saddle piece 85, a small hole 77 into which the tip of a metal wire 87 such as a mild steel wire whose tip is bent at a right angle is inserted. In a state where the mild steel wire 87 is inserted into the slide hole 80 of the bridge pin 102, the saddle piece 85 can move in the longitudinal direction of the string 6.

  (A) shows the attachment state of the saddle piece 85. A mild steel wire 87 whose tip is bent at a right angle is inserted into the small hole 77 of the saddle piece 85. The other end of the mild steel wire 87 is held through a bridge pin 102 having a slide hole 80 through which the mild steel wire 87 passes. The bridge pin 102 is fixed by inserting a tapered portion 103 into a hole 9 formed in the bridge 8. The mild steel wire 87 passed through the slide hole 80 is fastened and fixed by a screw 84. Thereby, if the screw 84 is tightened, the position of the saddle piece 85 attached to the tip of the mild steel wire 87 is maintained. When exchanging strings, the bridge pin 102 is pulled out from the hole 9, but if the screw 84 is not loosened at that time, the position of the mild steel wire 87 does not change and the position of the saddle piece 85 returns to the original position again. The position 85 is not displaced, and an accurate position once adjusted can be restored.

A tuning method in the example of FIG. 32 will be described. In a state where the screw 84 is loosened, the saddle piece 85 is not fixed, and has a structure that can move in the longitudinal direction of the string. The saddle piece 85 first string 6 ₁ rests, pitch when played pressing the 12th 12th fret, installed correctly octave higher becomes such a position from the pitch of the open string, in that state Screw 84 is tightened. Place the other saddle pieces with the same adjustment.

  The shape of the head 103 of the bridge pin 102 shown in (b) is not a conventional spherical shape, but may be a quadrangle, a hexagon, or a rectangle extending in the longitudinal direction of the string. By making the shape with a corner, the direction in which the bridge pin 102 is inserted into the hole 9 of the bridge 8 becomes clear.

  The fixing method of the mild steel wire 87 by the bridge pin 102 shown in (b) is shown in the saddle block 76 shown in FIG. 26 (a), the saddle piece 85 shown in FIG. 28 (a), and FIG. 29 (a). The saddle piece 85 and the T-shaped saddle piece 101 shown in FIG.

  The fret string instruments and auxiliary tools for fret string instruments that have been shown so far have been designed to minimize the pitch error when the strings are held on the fret by adjusting the position of each part after attaching the specified parts to the actual guitar. In this case, the optimum setting of the shape and size of the recess 40 provided in the nut auxiliary tool 39 shown in FIG. 16C is based on trial and error.

  Next, a description will be given of a method for obtaining a predetermined shape, dimensions, and setting position of a nut, a nut auxiliary tool, and a saddle block without trial and error.

  When a string is pressed on a fret, there is a phenomenon that the actual pitch becomes higher than the pitch that should be due to the position of the fret determined from the chord length ratio shown in Table 1. As shown in FIG. 4, this phenomenon is caused by an increase in the tension of the string due to the string being stretched when the string is pressed.

  The amount stretched when the string is pressed by the fret depends on the distance between the string and the fret, that is, how far the string is from the fret. The distance between the string and the fret is called the string height. When the string height is large, the amount of the string stretched when the string is pressed by the fret becomes large.

  In the case of a normal folk guitar, the string height is set to the value shown in Table 2. When the string length is 648 mm and the string height is set to the value shown in Table 2, the extension of the string when the 1st and 12th frets of the 1st and 6th strings are pressed is calculated by the Pythagorean theorem Then, it becomes like Table 3. As is apparent from this table, the string height of the sixth string is larger, so the string elongation value is larger.

  A value obtained by dividing the length when tension is applied by the length when tension is not applied is referred to as strain ε. The increased strain calculated for the string elongation shown in Table 3 is Δε. As shown in Table 4.

When a tension is applied to a material with little plastic deformation such as a piano wire, the stress σ, which is a value obtained by dividing the tension by the cross-sectional area of the material, is proportional to the increased strain ε.
σ = E · ε (1)
The proportional coefficient E is called the elastic modulus, longitudinal elastic modulus, Young's modulus, etc. of the material.
A diagram in which the horizontal axis is distorted and the vertical axis is stress is called a stress-strain diagram.

In a state before the string is pressed on the fret, a predetermined tension is applied so that the open string has a predetermined pitch. The tension is defined as the open string tension So, and the stress obtained by dividing the So by the cross-sectional area A of the string is defined as the open string stress σo.
σo = So / A (2)

  The chord stress σ increases by Δσ = E · Δε with respect to Δε with respect to the open chord stress σo. Δσ is called increasing stress. The situation is shown in FIG.

The stress of the string when the string is pressed on the fret is called the pressed string stress σp. Since σp = σo + Δσ, according to equation (2):
σp = σo + Δσ = So / A + E · Δε (3)
It becomes. At this time, the tension of the string is increased by ΔS = E · Δε · A from the initial open string tension So. ΔS is called increased tension.

In a hard steel wire such as a piano wire, the value of the elastic modulus E is usually 21,000 kg / mm ² . This is the value used when the string is used in a stress range where permanent deformation (permanent distortion) does not occur when the string is stretched with a predetermined tension. This also applies to the case of strings made of. Therefore, if Δε, which is an increase in distortion when the string is pressed on the fret, is known, the string stress σp when the string is pressed on the fret can be obtained by calculation.

  As a result, when the chord stress σp when the string is held on the fret is multiplied by the cross-sectional area A of the string (more precisely, the cross-sectional area of the core wire), the tension Sp when pushing the string on the fret is calculated. A value is obtained.

  As shown in Table 1, the frequency of the string when the fret is pressed is the frequency ratio (same as the frequency ratio) obtained from the fret position with respect to the frequency of the open string stretched with the tension So. Multiply value. That is, when the first fret is pressed, the frequency of the open string is multiplied by the frequency ratio Rf = 1.05946, and when the 12th fret is pressed, the frequency is added to the frequency of the open string. The frequency is multiplied by the ratio Rf = 2.000.

  When the string is pressed against the fret, the distortion of Δε increases in the string, and as a result, the vibration frequency when the tension of the string increases by ΔS = E · Δε · A and increases to the value of the string tension Sp. The tension of the string increases to the tension Sp at the time of pushing, and is obtained by multiplying the vibration frequency of the string by the frequency ratio Rf obtained from the fret position.

That is, when the frequency of the open string is fo, the ratio of the frequency when the string tension is increased to the string tension Sp by pressing the fret against fo is the frequency ratio obtained from the fret position. Is Rf, the actual frequency f when the string is held on the fret is obtained as follows. Note that Δf is referred to as a string pushing rate.
f = fo × Δf × Rf (4)

In a fret musical instrument such as a guitar, it is ideal that the actual frequency when a string is pressed on the fret is accurately pronounced according to the frequency ratio obtained from the fret position. That is, the ideal frequency is
f = fo × Rf (5)
It is.

  However, as is apparent from the above calculation formula, the frequency of the sound actually generated is higher by Δf than the ideal frequency. This is the madness of the actual pitch.

The string raising rate Δf is obtained as follows from the expression of the string sound pitch (natural frequency of the string) described in the background art.
When the string length is l, the open string tension is So, the string unit length weight is γ, and the gravitational acceleration is g, the open string frequency fo is
fo = (1/2 · l) · [So · g / γ] ^1/2 (6)
It is.
When the string tension increases by ΔS, the frequency f is
f = (1 / 2l) · [(So + ΔS) · g / γ] ^1/2
Therefore, the rate of increase Δf when the string is pressed is
Δf = f / fo = [1 + ΔS / So] ^1/2
It becomes.

Here, since ΔS = E · Δε · A,
Δf = [1 + Δε · (E · A / So)] ^1/2
Here, if Ke = E · A / So,
Δf = [1 + Ke · Δε] ^1/2
It becomes.
Since σo = So / A,
E · (A / So) = E / σo.
E. (A / So) = Ke (7)
And Ke is called a chord coefficient.

When the value of Δf = Ke · Δε is sufficiently smaller than 1,
Δf = 1 + Ke · Δε / 2 (8)
And can be approximated.

The value of the chord coefficient Ke is obtained from the value of the elastic modulus E determined from the open chord tension So of the chord, the cross-sectional area A and the chord material. Table 5 shows Ke obtained by calculating the E / σo by obtaining the string stress σo from the cross-sectional area A and the open string tension So for a steel string having an elastic modulus E of 21,000 kg / mm ² .

  From the string distortion Δε and the chord coefficient Ke of the first and sixth strings obtained in Table 5, the first and twelfth frets of the first and sixth strings shown in Table 4 were pressed. Table 6 shows the string raising rate Δf calculated by the time equation (5).

  When the string is held on the frets, the frequency of the sound that is actually generated is obtained by f = fo × Δf × Rf in the equation (4), so the first and twelfth frets of the first and sixth strings. Table 7 shows a result of comparison between the actual frequency when the pressure is held and the frequency obtained from f = fo × Rf in the equation (5) which is an ideal frequency.

  The numerical value of the frequency difference obtained in Table 7 seems to be small at first glance, but in reality, the frequency when the first fret of the sixth string is pressed is 0.62 Hz higher than the ideal frequency. In this case, when the value is converted to a unit in which a semitone of equal temperament is 100 cents, it becomes a value of about 13 cents, which means that a sound deviation of 13% of the semitones has occurred.

  The frequency when the 12th fret of the first string is pressed is 2.11 Hz higher than the ideal frequency, or the frequency when the 12th fret of the 6th string is pressed is ideal. When the frequency becomes 1.96 Hz higher than the vibration frequency, if another sound having the correct pitch is sounded at the same time, about two beats occur per second.

In the case of a steel string, since there is almost no plastic deformation, the value of the elastic modulus E can be assumed to be a constant value of 21,000 kg / mm ² .
However, in the case of a string using a polymer material such as nylon used in classic guitars, the value of the elastic modulus E changes depending on the tension of the string. In other words, permanent deformation (permanent strain) remains due to plastic deformation. Therefore, the value of the elastic modulus E cannot be treated as a constant value as in the case of steel strings.
Next, a method for obtaining the value of the elastic modulus E applied to a nylon string or the like will be described.

  Guitars that use nylon strings are called classic guitars. As shown in FIG. 34, the nylon strings used for classic guitars are roughly two types of strings.

  One is a string composed of the nylon monofilament 110 shown in (a). As an example, the first string of the classic guitar is 0.72 mmφ, the second string is 0.82 mmφ, and the third string is A nylon monofilament 110 having a diameter of 1.01 mm is used. Since the density of nylon is about 1.14, the nylon monofilament 110 has a thicker string than a steel string in order to secure a unit weight γ.

  Another type of string is a winding formed by bundling hundreds of ultrafine nylon floss fibers of about 15-20 μmφ shown in (b) to form a multifilament 111, and then winding a silver-plated bronze wire 112 thereon. It is a string. In the case of a string having this structure, the bronze wire 112 is for securing the weight of the string, and the tension of the string does not act on that portion. All the tension is applied to the nylon multifilament 111.

  As an example, the fourth string of a classical guitar is a wound string with an outer diameter of 0.72 mmφ formed by winding a bronze wire of 0.135 mmφ around a nylon multifilament 111 made of 271 nylon floss fibers of 20 μmφ, Nylon multifilament 111 consisting of 267 nylon floss fibers of 20 μmφ as 5 strings, a wound string of 0.91 mmφ with a bronze wire of 0.225 mmφ, and 273 nylon floss fibers of 20 μmφ as the 6th string A wound chord having an outer diameter of 1.10 mm and having a bronze wire of 0.335 mm wound on a nylon multifilament 111 made of

  It is known that when an external force (tension) is applied to a string made of a polymer material such as nylon, the deformation (string elongation) of the material increases with time and a creep phenomenon occurs. A value obtained by dividing the amount of elongation by the length before applying the tension is referred to as creep strain. Table 8 and FIG. 35 show the results of measuring the creep strain (%) that changes over time for the six nylon strings of the above example.

  A string made of nylon monofilament 110 has a large creep strain when the open string stress σo is large, and continues to grow slightly even after about 100 hours. On the other hand, the winding string in which the nylon multifilament 111 is used for the core wire has a relatively small creep strain value, and the creep strain stops increasing after a short time.

  For nylon strings that exhibit such characteristics, after the string has almost stopped growing, adjust the string tension to the predetermined open string frequency, and then adjust the string tension until the frequency increases correctly by a semitone. The amount of elongation at that time was measured.

  Actually, when two strings of 500 mm intervals are marked on the string in a state that matches the predetermined open string frequency, and the string tension is increased from that state until the frequency is correctly increased by a semitone. The distance between the two marks was measured.

When the interval of the mark measured when the tension of the string is increased is L mm, the value of the semitone distortion Δεs when the frequency of the string becomes a semitone is expressed as follows.
Δεs = (Lmm−500mm) / 500mm (9)

  The first, second, and third strings of nylon monofilament 110 have a large semitone distortion Δεs when the open string stress σo is large, and the wound string in which the nylon multifilament 111 is used as the core is originally a string. Since it is used in a place where the stress is very large, the value of the semitone distortion Δεs is large and almost the same value was measured.

  Next, a calculation method for obtaining the value of the string coefficient Ke of a string using a polymer material such as nylon from the measured semitone distortion Δεs will be described.

  FIG. 36 shows a stress-strain diagram of a nylon string. When the tension is first applied to the string to increase the vibration frequency of the string to a predetermined open string tension, the strain and stress increase along the curve OA.

  After the frequency of the open string reaches a predetermined frequency, as shown in FIG. 36, a creep phenomenon occurs in the string, and even if the tension is kept at a predetermined value, It increases with the passage of time. The situation follows a straight line AB. After a long time, the state where the creep distortion stops is point B, and in the case of an actual guitar, it is used in such a state.

As shown in the equation (6), the relationship between the tension S and the frequency f is S∝f ² , and the frequency ratio Rf of the semitone is 1.05946 as shown in Table 1. The string tension at the frequency of the open string, So, and the tension Ss when the string tension is increased until the frequency increases by a semitone have the following relationship.
Ss = So × 1.05946 × 1.05946

Therefore, the tension increase ΔS for raising the frequency of the string by a semitone can be calculated as follows.
ΔS = So × (1.05946 × 1.05946-1) (10)

A value ΔS / A obtained by dividing the tension increase ΔS by the chord core area A is an increased stress Δσs for raising a semitone, and this Δσs is referred to as a semitone stress.
The relationship between the semitone distortion Δεs and the semitone stress Δσs can be regarded as a linear relationship indicated by BC in FIG. 36 because the value of the semitone distortion Δεs is small, and the proportionality coefficient is treated as the elastic coefficient E. be able to.
In this way, the relationship between the semitone distortion Δεs and the semitone stress Δσs is as follows.
Δσs = E · Δεs (11)

Since Δσs = ΔS / A, according to the equations (10) and (9),
Δσs · A = ΔS = So (1.05946 × 1.05946-1)
It becomes. Substituting Δσs = E · Δεs into this,
E · A / So = (1.05946 × 1.05946-1) / Δεs
Where Ke = (A / So) × E.
Ke = (1.05946 × 1.05946-1) / Δεs (11)
It is.

  That is, even in the case of a string using a polymer material such as nylon, the value of the string coefficient Ke can be obtained by measuring the value of the semitone distortion Δεs.

  Table 9 shows the calculation results of the open string tension So and the open string stress (σo = So / A), the measured semitone distortion Δεs and the string coefficient Ke for the six nylon strings in the above example. Shown in

  If the value of the string coefficient Ke is known, as in the case of the steel string, the string raising rate Δf can be obtained by Δf = 1 + (Ke × Δε) / 2 of the approximate expression (7), and when the fret is pressed The frequency f of the string can be obtained by calculation from f = fo × Δf × Rf in equation (4).

  In FIG. 36, when the tension is gradually relaxed from the point B of the tension of the open string, the stress and strain decrease along the curve BD. Even when the tension (stress) of the string becomes completely zero, the distortion of the string does not return to zero, and a permanent distortion of the OD size remains. This permanent set is usually large in nylon monofilament using a polymer material.

  For monofilaments using a polymer material, in addition to nylon (density: about 1.14) which is a polyamide resin, Kevlar (registered trademark) (density: about 1.38) of aramid resin and carbon fiber (density: About 1.8) and composite material Nile Gut (registered trademark) (density: about 1.3) are used. In addition, since the development of high-molecular materials in classical guitars, various strings have been used, such as the gut string (density: about 1.35) that is made by processing the fiber of sheep's intestine into a single string. .

  For these monofilaments, the value of the semitone distortion Δεs was measured, and the value of the chord coefficient Ke obtained using the value was shown in Table 10, and the plotted graph is shown in FIG.

When the string of any material is used in a state where the string stress is large, the value of the string coefficient Ke is small, and therefore the pitch deviation when the string is pressed on the fret is small. It can be considered that the chord coefficient Ke is inversely proportional to the stress of the chord.
In the case of gut strings that have been used before the development of polymer materials, the value of the string coefficient Ke is smaller than that of monofilaments of polymer materials. Smaller than monofilament of polymer material.

  Several hundreds of nylon floss fibers of about 15-20 μmφ are bundled into a multifilament 111, and a winding string formed by winding a silver-plated bronze wire 112 thereon, the value of the semitone distortion Δεs is measured, As a result of calculating the value of the chord coefficient Ke using the value, the chord coefficient Ke is obtained by the difference in the diameter of the nylon floss, the difference in the number, the difference in the thickness of the bronze winding, and the like. Although there is a difference, the value of Ke is in the range of about 50 to 60, and the difference due to the thickness of the string is very small. That is, the fourth string, fifth string, and sixth string, in which a wound string is used in a classic guitar, have a small pitch error when the string is held on the fret.

In the case of steel strings, we measured the semitone distortion Δεs from the first string to the sixth string of three types of strings: two types of low tension (Light Tension) and one type of medium tension (Medium Tension). From this value, the value of the chord coefficient Ke was obtained.
The calculated chord coefficient Ke is shown in Table 11 and plotted is shown in FIG.

The line in FIG. 38 is obtained by obtaining the chordal coefficient Ke with the value of the elastic modulus E being a constant value of 21,000 kg / mm ² , but the data plotted as the actual measurement value is on the line. From this, in the case of a steel string, it can be said that it is appropriate to obtain the string coefficient Ke by setting the value of the elastic coefficient E to a constant value of 21,000 kg / mm ² .

Next, an embodiment in which the principle described so far is applied to a guitar will be described. This principle makes it possible to numerically set the optimum shapes and dimensions of the nut auxiliary tool and the saddle block in advance of trial and error according to the type of string used and the string height.
Also, even when the type of string used and the string height change, it is possible to prepare multiple parts with different setting values in advance, and it is possible to provide a guitar that can flexibly handle various conditions It becomes.

FIG. 39 shows an embodiment in which this configuration is applied to the nut auxiliary tool 39 shown in FIG.
A nut auxiliary tool 39, which is a trapezoidal flat plate, is disposed on the fingerboard 11 with one end in close contact with the nut 13. Strings ₆₁ on the upper surface thereof, ..., the grooves ₁₂ 1 for guiding the _{6 6,} ..., 12 ₆ are formed. The surface opposite to the surface in close contact with the nut, the strings ₆ 1, ..., recesses ₄₀ 1 for adjusting the _{6 6} support position, ..., 40 ₆ are formed. Length or groove ₁₂ 1 of the nut 13 to the recess 40 for adjusting the support position, ..., length .DELTA.N ₁ 12 _6, ... .DELTA.N ₆ intersects the chord ₆ 1, ..., q _{6 6} Each is set to a different value.
Thus, the nut 13 is first fret 10 ₁ intervals, .DELTA.N ₁ than the normal interval, only · · · .DELTA.N _6, it is shorter in each string.
Next, a method for obtaining an appropriate value of ΔN will be described with reference to FIG.

FIG. 40 (a) shows the relationship between the fret and the string when the nut auxiliary tool is not used.
Distance L from the nut 13 to the saddle 14 is called the reference scale length, first fret 10 ₁ is disposed at a position where the chord length ratio shown in Table 1 to that number as a reference. Position where the first fret 10 ₁ is arranged, when the frequency of the open string 1.00000, frequency is the position to be 1.05946, specifically pressed the first fret 10 ₁ If the position of the chord length _{L 1} is L / 1.05946 in.
The first fret is arranged at a position where the chord length L ₁ = 611.632 mm when the reference scale length L is 648 mm, and at a position 36.368 mm (= 648 mm−611.632 mm) from the nut 13.

Frequency when the pressing of the first fret 10 ₁ position, if the frequency of the open string was 1.00000, be disposed at a position where the ideal frequency of 1.05946, a chord first by pressing one fret 10 _1, as a result of the strings are slightly stretched, and string tension is increased, the sound is actually sound becomes higher than the sound that would depend fret position.

As in the specific example and Table 7, in the case of the first string ₆₁ in the first fret, in 0.64Hz, in the twelfth fret generated phonetic elevated 2.11 Hz, string 6 in the case of 6 ₆ in the first fret, the 0.62 Hz, pronunciation elevated 1.96Hz occurs at the 12th fret.

(B) it is shows the relationship between the fret and the string in the case of using the nut aid 39, the first string ₆₁ as an example.
By using the nut aid 39, the chord length of the open string of the string ₆₁ is being shortened in length .DELTA.N ₁ grooves 12 ₁ from the reference scale length L, which is the (L-ΔN _1).

Relative chord length of shortened open string, the frequency ratio Rf _{1, 1} of the chord length _L 1,1 = _L /1.05946 when holding down the first fret 10 _{1,
Rf 1,1 = (L -ΔN 1)} / (L /1.05946)
= 1.05946 × (L−ΔN ₁ ) / L
It is.

When the string is pressed on the first fret, the frequency rises as shown in the equation (8) and Table 7, so that a string with the frequency ratio Rf _1,1 is pressed in order to produce a sound with the correct frequency. The value multiplied by the rate of increase Δf ₁ needs to be 1.05946, which is the ideal frequency ratio pressed against the first fret. That is,
Δf ₁ × 1.05946 × (L−ΔN ₁ ) /L=1.05946
And from this,
ΔN ₁ = L × (1-1 / Δf ₁ ) (12)
It becomes.

The first fret shortening amount ΔN ₁ depends on an approximate expression Δf ₁ = 1 + (Ke × Δε ₁ ) / 2 of the string raising rate.
Since the string coefficient Ke is a numerical value obtained from the open string tension So, the cross-sectional area A, and the elastic coefficient E of the string as shown in Equation (7), it is determined in advance as a unique value if the string to be used is determined. .
Further, the distortion increase value Δε ₁ in the first fret can be easily obtained from the Pythagorean theorem from the string height and the string length.

Therefore, Ke is determined according to the type of string to be used, Δε ₁ is obtained from the string height and string length, an approximate value of Δf ₁ is calculated therefrom, and the obtained Δf ₁ value and the string length are obtained from the obtained value. A 1-fret shortening amount ΔN ₁ is calculated.
That is, the first fret shortening amount ΔN ₁ has a chord coefficient Ke of E · (A / So) = Ke according to the equation (7), and therefore, the string rising rate Δf ₁ when the first fret is pressed is Δf ₁ = 1 + [(A / So) × E × Δε ₁ ] / 2, and the first fret shortening amount ΔN ₁ is given by the equation (12):
ΔN ₁ = L × [1-1 / {1 + [(A / So) × E × Δε ₁ ] / 2}] is calculated.

Table 12 shows an example of the value of the first fret shortening amount ΔN ₁ calculated in this way for each of the steel strings shown in Table 5.

According to the calculation result, the value of the first fret shortening amount ΔN ₁ is different for each string, and the shortening amount of the first string 1.18 mm is 3 with respect to the conventional first fret position 36.368 mm. The fact that the 6th string should be shortened by 4.54mm indicates that it should be shortened by 2%.

According to this table, the second string should be shortened by 6.3%, the third string by 3.8%, the fourth string by 4.8%, and the fifth string by 7.1%. Since the value of the first fret shortening amount ΔN ₁ shown here is a calculation example when the chord height is set to a slightly high value, if the chord height is set low, the value of the first fret shortening amount ΔN ₁ is Get smaller.

As a result of shortening the interval between the nut 13 and the first fret, the frequency of the sound actually produced when the first fret is pressed is exactly 1.05946 higher than the frequency of the open string. It becomes the frequency. If you press the second fret 10 _2, the position of the second fret, to the frequency of the first fret, because correctly 1.05946 only high sound Could position, in which case the correct frequency also Sound is produced.

However, regarding the position of the fret, it is necessary to consider the case where the dimensions are not accurate due to factors such as manufacturing errors. Taking these into consideration, by using a value of the first fret shortening amount ΔN that is about 10 to 20% smaller than the above calculation result, the frequency of sound determined by each fret is slightly determined by the equal temperament. Although it is higher than the frequency, it is possible to avoid a fatal situation where the frequency becomes too low.
This value is optimally about 10% for steel strings and about 20% for nylon strings.

Next, the calculation of the saddle position adjustment amount in FIG. 8 will be described.
When the 12th fret, which is the center of the guitar fret, is pressed, it should sound at twice the frequency of the open string. The frequency of the sound that is pronounced will be higher than twice the frequency of the open string.
The purpose of adjusting the saddle position is to prevent such a situation.

Although reference dimension from the first string ₆₁ of the 12th fret to the saddle is half the value of the reference scale length L, its length, the position of the plus saddle correction value Δ L (L / 2 + Δ L) By placing a saddle and increasing the length of the string from the 12th fret to the saddle, the frequency of the sound produced when the 12th fret is pressed is accurately set to twice the frequency of the open string.

The string raising rate Δf ₁₂ when the twelfth fret is pressed is obtained by the approximate expression Δf ₁₂ = 1 + (Ke × Δε ₁₂ ) / 2. The distortion increase value Δε ₁₂ when the 12th fret is pressed is a relatively large value because the string height of the 12th fret portion is large.

The numerical value of the saddle correction value ΔL is obtained from the relationship f = fo × Δf ₁₂ × Rf. When the saddle correction value is ΔL , the distance between the 12th fret and the saddle is ( L / 2 + ΔL ), and the dimension of the open string is ( L + ΔL ). Therefore, the frequency ratio Rf _1,12 of the twelfth fret is
Rf _1,12 = ( L + ΔL ) / ( L / 2 + ΔL )

Therefore, when the 12th fret is pressed, the frequency of the sound that is actually sounded is expressed as follows:
f _1,12 = fo × Δf ₁₂ × (L + ΔL) / (L / 2 + ΔL)
This is because the frequency when the 12th fret is pressed should be double the open string correctly,
f _1,12 = 2 × fo
It is.

Therefore,
2 = Δf ₁₂ × (L + ΔL) / (L / 2 + ΔL)
The value of become ΔL is, from the saddle correction value ΔL,
ΔL = L × (Δf ₁₂ −1) / (2-Δf ₁₂ )
Thus, the value of the saddle correction value ΔL can be obtained.
That is, the saddle correction value ΔL is
Since the string coefficient Ke is E × (A / So) = Ke according to the equation (7), the string rising rate Δf ₁₂ when the 12th fret is pressed is
Δf ₁₂ = 1 + [(A / So) × E × Δε ₁₂ ] / 2
The saddle correction value ΔL is
ΔL = L × [{1 + [(A / So) × E × Δε ₁₂ ] / 2} −1]
/ [2- {1 + [(A / So) × E × Δε ₁₂ ] / 2}]
Is calculated as

Table 13 shows an example of the saddle correction value ΔL. The string is a steel string of a folk guitar shown in Table 5, the string height is set to the value shown in Table 13, and a value calculated by ΔL = L × ( Δf ₁₂ −1) / (2− Δf ₁₂ ). The reference scale length L of this guitar was 648 mm, and the first fret shortening amount ΔN ₁ was set to ΔN ₁ = 0. According to the calculation result, the saddle correction amount ΔL of the second chord with a thick outer diameter is large in the first chord and the second chord in which the steel single wire is used.

  In the case of a bronze wound string, since the string tension acts on the core wire portion, the saddle correction amount ΔL is determined according to the value of the string coefficient Ke depending on the core wire diameter. The value of the saddle correction value ΔL shown here is a calculation example when the string height is set to a slightly high value. Therefore, if the string height is set to a low value, the value of the saddle correction value ΔL becomes a small value. Is clear.

  The value of the saddle correction value ΔL in Table 12 shows the same tendency as the saddle 72 of the conventional example shown in FIG. However, in the case of the conventional example, the side of the adjustment saddle is shaved diagonally by trial and error so that the pitch when played by pressing the 12th fret is exactly one octave higher than the pitch of the open string. The saddle block adjustment position can be set numerically in advance by introducing the above calculation method, so even if the strings to be used change, etc. It can be easily adapted by changing to a saddle.

FIG. 8 shows a case where only the position of the saddle block is adjusted without using a nut auxiliary tool. However, when the nut auxiliary tool shown in FIG. 39 is used, the length of the open string is different from the conventional one. Since it is shortened, the position of the saddle block needs to be adjusted accordingly.
The adjustment amount is obtained by subtracting the first fret shortening amount ΔN ₁ from the saddle correction amount ΔL, and saddle block correction amount ΔLn = saddle correction amount ΔL−first fret shortening amount ΔN ₁ , that is, using a nut auxiliary tool. In this case, the saddle block correction amount ΔLn is
ΔLn = L × [{1 + [(A / So) × E × Δε ₁₂ ] / 2} −1]
/ [2- {1 + [(A / So) × E × Δε ₁₂ ] / 2}]
−L × [1-1 / {1 + [(A / So) × E × Δε ₁ ] / 2}]
Is calculated as
As an example, the saddle correction amount ΔL shown in Table 13 is subtracted from the first fret shortening amount ΔN shown in Table 12, and Table 14 shows the saddle block correction amount ΔLN.

  As described above, the arrangement positions of the nut, the nut auxiliary tool, and the saddle block can be obtained without trial and error.

  Generally, strings used in guitars are sold with the structure, material, thickness, tension, etc. of the strings specified as attached information. This time, if the value of the string coefficient Ke described in the above example is displayed, guitar production or production of a guitar with little pitch error using an existing guitar with nuts and nut assistants and saddle blocks This information is useful when you want to adjust an off-the-shelf guitar.

  As shown in FIG. 7, the saddle 14 of the folk guitar is inserted into the saddle groove 71 of the bridge 8. In the case of such a saddle 14, the string lengths of all the strings cannot be accurately adjusted.

  Even in the case of the saddle 72 whose side surface is cut obliquely as shown in FIG. 8, when the string to be used is changed, the appropriate value of the position on which the string is placed changes, so that it is necessary to replace it with another saddle. .

FIG. 41 shows an embodiment of a saddle block according to the present invention.
If the saddle piece 113 that can be selectively incorporated as shown in (a) is used, the string length of all the strings can be set to a correct value, and even if the strings to be used are changed, the changed strings can be changed. This can be done by replacing only the corresponding saddle piece.

  A leg portion 114 to be inserted into the saddle groove 71 is formed at the lower portion of the saddle piece 113 shown in (a). A top portion 94 on which a string is placed is formed at the upper portion, and the lower portion of the top portion 94 is connected to the bridge 8. The bottom surface 115 is used for mounting. The height of the leg 114 may be slightly shorter than the depth of the saddle groove 71. The thickness of the leg 114 is preferably a thickness that can be inserted into the width of the saddle groove 71 without a gap.

  As shown in FIG. 7, the saddle groove 71 into which the saddle 14 of the folk guitar is inserted is disposed obliquely on the bridge 8. The saddle 14 is inserted into the saddle groove 71 provided as a result.

The inclination is slightly less than 6 mm on the first string side and the sixth string side. In the case of such a saddle 14, the saddle upper surface of the conventional saddle 20 shown in FIG. Whereas it is formed on the far side, the position of the top portion 94 of the saddle piece 113 disposed at the position shown as the saddle block correction amount ΔLN in Table 14 is all on the nut side with respect to the saddle groove 71.
Therefore, the saddle piece 113 has a shape in which the top portion 94 is offset with respect to the leg portion 114 as shown in FIG.

If a plurality of types having different offset amounts are prepared, it is possible to easily cope with changing the string.
The saddle piece 113 includes only one string shown in (a), two strings shown in (b), three other strings, and four strings. There are those that appear on the book and those that appear on the book.
It is also possible to form a string groove 100 through which the string passes in the top part 94.

  The saddle piece 113 may be made by molding a plastic product, or by cutting animal bones or metal.

  In the case of a classic guitar using nylon strings, it may be an integral shape having a top portion 94 arranged offset.

(C) shows a state in which the saddle piece 113 is attached. The leg portions 114 of the plurality of saddle pieces 113 are inserted into the saddle grooves 71 of the bridge 8. A saddle piece 113 having a different offset amount for each string is incorporated in each string 6 so that the string length becomes a predetermined length.
With such a configuration, it is possible to accurately match the sound when the 12th fret is pressed with the sound one octave above the open string.

  If it is necessary to further adjust the string height, the height of the top 94 can be trimmed to adjust the value. As an example, when the center line is displaced by 0.5 mm, the offset amount between the top 94 and the leg 114 is about 10 types, ranging from a minimum of 0.5 mm to 5.0 mm. If so, it is possible to cope with most of the strings used.

  It has been described above that a steel string used for a folk guitar has a string coefficient Ke specific to the string according to the structure and thickness of the string. By selecting a string to be used for the guitar, the position of the top portion 94 on which the string of the saddle piece 113 is placed can be predicted and determined in advance by calculation. The width of the saddle groove 71 provided in the bridge 8 of a normal folk guitar is 3.2 mm at most. With a single saddle having a thickness that fits into the groove of this width, the string length cannot be set to a predetermined length for each string.

  Regarding strings used in guitars, when the density of the materials used is the same, there is a relationship that the stress of the strings is constant even if the thickness changes and the tension of the strings changes. For example, in the case of a steel string of a folk guitar (a string whose core wire is made of a piano wire), a steel single wire string is used for the first string and the second string.

  Since string tension affects performance, various types of strings are used, such as low tension strings (Light Tension) and medium tension strings (which can be set low). However, both the first and second strings use piano wire as the material, and the density of the material is a constant value of about 7.9.

  In this case, even if the thickness of the string changes, the string stress when the string is stretched to a predetermined frequency is the same. Therefore, the value of the string coefficient Ke is constant regardless of the thickness of the string. is there.

  As described above, when different types of strings are used, it is necessary to incorporate the saddle piece 113 so that the string length is different for each string so that the string length becomes a predetermined length for each string 6. However, since the string coefficients Ke of the first and second strings do not change, it is not necessary to change the saddle piece 113 for those strings, and only the saddle piece 113 that needs to be changed may be selectively incorporated. .

  If the saddle piece 113 of the present embodiment is used, it is possible to selectively use the saddle piece 113 having a different amount of difference for each string, so that the pitch of the guitar can be accurately adjusted.

  Further, when the nut and the nut auxiliary tool of the present invention are mounted on a ready-made guitar in which the saddle groove 71 is already carved in the bridge 8, the position of the saddle is the conventional ideal saddle position shown in Table 13. Therefore, as shown in Table 14, the position of the saddle is required to be shifted by about 1 to 4 mm on the nut side.

  Even in such a case, by using the saddle piece 113 having the top portion 94 on which the string is placed at a position different from the leg portion 114 inserted into the saddle groove 71, the string length is set to a predetermined length for each string. The length can be set.

  FIG. 42 shows an embodiment in which the saddle piece is used together with the under saddle pickup. The leg 114 of the saddle piece 113 on which the string 6 shown in (a) is placed is placed on a piezo pickup 90 placed in a saddle groove 71 formed in the bridge 8. In the saddle piece 113 shown in (b), a top portion 94 on which a string is placed is formed at a position offset from the leg portion 114. A bottom surface 115 for mounting on the bridge 8 is formed below the top portion 94.

  The bottom surface 115 constitutes an extension 116 extending in a direction opposite to the top portion 94 with respect to the leg portion 114. An end portion of the extension 116 serves as a fulcrum portion 97. The saddle piece 113 may be made by molding a plastic product, or by cutting animal bones or metal.

  A cross-sectional view of the saddle piece 113 of this embodiment is shown in FIG. The string 6 is fixed at one end in the hole 9 formed in the bridge 8 and rests on the top 94 of the saddle piece 113 and is stretched along the fingerboard 11 in which the fret 10 is embedded. A predetermined tension is applied to the string 6 by being placed on a nut auxiliary tool arranged at the end of the fingerboard that is not to be guided and being wound up by a gear tuner guided by a groove provided in the nut.

  Since the leg 114 of the saddle piece 113 is partly placed on the piezo pickup 90 placed in the saddle groove 71 formed in the bridge 8, a predetermined tension is applied to the string 6. When this occurs, the fulcrum 97 at one end of the saddle piece 113 is pressed against the upper surface of the bridge 8. When the string 6 vibrates in this state, the force acts on the top 94 of the saddle piece 113, and the "principle principle" causes the string to reach the action point 98, which is the contact point between the leg 114 of the saddle piece 113 and the piezo pickup 90. 6 vibration force acts.

  Thus, the vibration of the string 6 is transmitted to the piezo pickup 90 through the leg portion 114, and an electric signal is generated. The electric signal is transmitted to the sound loudspeaker (amplifier) via the lead wire 91.

  In order to effectively transmit the vibration force of the string 6 to the piezo pickup 90, the fulcrum portion 97 at one end of the saddle piece 113 mounted on the bridge 8 is an operating point that is a contact point between the leg portion 114 and the piezo pickup 90. It is desirable that the end portion is opposite to the top portion 94 with respect to 98.

  The method of using the saddle piece 113 used together with the under saddle pickup is exactly the same as the embodiment described in FIG. 41 except for the under saddle pickup portion.

  The following embodiment is an example of a combination of the above embodiments although not shown. Generally, strings used in guitars are sold with the structure, material, thickness, tension, etc. of the strings specified as attached information.

  This time, if the value of the string coefficient Ke described in the above example is displayed, guitar production or production of a guitar with little pitch error using an existing guitar with nuts and nut assistants and saddle blocks It is clear that this is useful information when adjusting an off-the-shelf guitar. However, as an example, the nut auxiliary tool 39 described in FIG. It is also effective to provide an object corresponding to six strings and an object corresponding to the six strings of the saddle piece 113 described with reference to FIG. As a result, even a general user can easily change a ready-made guitar to a guitar with no pitch deviation.

As mentioned above, the embodiment of the present invention has been described with a folk guitar as a representative example. However, the present invention supports a guitar other than a folk guitar, mandolin, electric guitar, eye, which supports strings with nuts and saddles, and determines the pitch of strings by frets. It can also be applied to Rishbuzouki, banjo, ukulele, and even a titer.
Further, it goes without saying that the present invention can be applied not only to modification of an already-made musical instrument but also to a newly produced musical instrument.

The perspective view of a folk guitar. Illustration of folk guitar strings. Explanatory drawing of the relationship between a nut and a fret of a guitar. Explanatory drawing at the time of the performance of the conventional guitar. Explanatory drawing of the conventional improved nut. Explanatory drawing of the other conventional improved nut. Explanatory drawing of the conventional saddle. Explanatory drawing of the conventional improved saddle. Explanatory drawing of the other conventional saddle improved. Explanatory drawing of the conventional under saddle pickup. Explanatory drawing of the further another conventional nut improved. Explanatory drawing of the 1st Example of a nut. Explanatory drawing of the 2nd Example of a nut. Explanatory drawing of the 3rd Example of a nut. Explanatory drawing of the 1st Example of a nut auxiliary tool. Explanatory drawing of the 2nd Example of a nut auxiliary tool. Explanatory drawing of the 3rd Example of a nut auxiliary tool. Explanatory drawing of the use condition of a nut auxiliary tool. Explanatory drawing seen from the side of the usage condition of a nut auxiliary tool. Fig. 4 is a diagram illustrating the use situation of a nut auxiliary tool and a conventional improved saddle. Explanatory drawing of the 4th Example of a nut auxiliary tool. Explanatory drawing of the 5th Example of a nut auxiliary tool. Explanatory drawing of the 6th Example of a nut auxiliary tool. Explanatory drawing of the 7th Example of a nut auxiliary tool. Explanatory drawing of the 8th Example of a nut auxiliary tool. Explanatory drawing of the 9th Example of a nut auxiliary tool. Explanatory drawing of the Example of the saddle divided into 3 parts. Explanatory drawing of the Example of the saddle divided into 6 parts. Explanatory drawing of the Example of the saddle which an under saddle pickup cooperates. The detailed explanatory view of the example of the saddle which the under saddle pickup cooperates. Explanatory drawing of the other Example of the saddle which an under saddle pickup cooperates. Explanatory drawing of other Example of the saddle which an under saddle pickup cooperates. Stress-strain diagram of hard steel wire Nylon string structure illustration Nylon string creep strain diagram Nylon string stress-creep strain diagram Monofilament chord stress-chord coefficient diagram Steel string chord stress-chord coefficient diagram Explanatory drawing of the 10th Example of a nut auxiliary tool. Explanatory diagram of the method for obtaining ΔN Illustration of an example of a saddle piece Explanatory drawing of the further another Example of the saddle which cooperates with an under saddle pickup. Detailed explanatory diagram of the saddle cooperating with the under saddle pickup.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Front plate 2 Back plate 3 Side plate 4 Resonance drum 5 Neck 6 String 6 ₁ 1st string 6 ₂ 2nd string 6 ₃ 3rd string 6 ₄ 4th string 6 ₅ 5th string 6 ₆ 6th string 7 Gear tuner 8 Bridge 9 Hole 10 Fret 10 ₁ 1st Fret 10 ₂ 2nd Fret 10 ₃ 3rd Fret 10 ₁₁ 11th Fret 10 ₁₂ 12th Fret 11 Fingerboard 12 Groove
12 ₁ , _{1 2 6} support groove 13, 15, 18, 21, 24, 36, 61 nut 14, 20 saddle 16, 19 nut groove 17 ₁ support position of 1st string 6-1 17 _{6 of} 6th string 6-6 Support position 22 Finger 23 Attaching portion 25 Nut attachment location 26 Extension portion 31, 32, 34, 41, 41 ₁ , 41 ₂ , 41 ₃ Nut auxiliary tool 33 Top surface 35 Frustum 37, 49, 52, 62, 66 Long hole 38 , 51 Screw 42 Flat part 43 Half round bar 44 Mild steel wire 45 Connection part 46, 50 Thin plate 47 Hook 48 Embedding member 53 Fixed piece 54 Strip piece 55, 56 Strip piece 57 Fixed part 58 Rod cover 59, 60, 63, 67 Stop Screw 61 Single string nut 64 Nut mounting part 65 Dual string nut 71, 73 Saddle groove 72 Adjusting saddle 74 ₁ , 74 _{2, 74 3,} 74 _4, 74 5, 74 ₆ adjusted saddle top 75 flats 76 saddle block 77 eyelet 78 mild steel wire 80 slide hole 81 bridge block 82 small screw 83 threaded hole 84 screw 85 saddle piece 86 flat portion 87 Mild Steel Wire 90 Piezo pickup 91 Lead wire 92 Saddle extension 93 Block part 94 Top part 95 Slope 96 Guide part 97 Support point part 98 Action point 99 Recessed part 100 String groove 101 T-shaped saddle piece 102 Bridge pin 103 Taper part 104 Head part 105 Slot 110 Nylon monofilament 111 Nylon floss 112 Winding 113 Saddle piece 114 Leg 115 Bottom 116 Extension

Claims (1)

A fret stringed instrument having a nut and a saddle for supporting both ends of a string, and a plurality of frets disposed between the nut and the saddle,
The fret string instrument has a nut auxiliary tool that is disposed in contact with the nut and supports the nut side end of the string, and a shortening amount ΔN of each string by the nut auxiliary tool is ΔN = L × [1-1 / {1 + [(A / S) × E × Δε ₁ ] / 2}]
And the extension amount ΔLn of each string by the saddle is
ΔLn = L × [{1 + [(A / S) × E × Δε ₁₂ ] / 2} −1] / [2- {1 + [(A / S) × E × Δε ₁₂ ] / 2}] − L × [1-1 / {1 + [(A / S) × E × Δε ₁ ] / 2}]
Where L: reference chord length for determining fret position,
E: Young's modulus of the string in actual use,
A: cross-sectional area of the string,
S: Open string tension,
Δε ₁ : String extension when the string is pressed against the first fret / Open string length
[Delta] [epsilon] ₁₂ : A fret stringed instrument with the amount of string extension / open string length when the string is pressed against the 12th fret.

Images