MXPA97006126A - Automatic tuner of cuer instrument - Google Patents

Abstract

The present invention relates to an apparatus for tuning a string musical instrument, the apparatus comprising: a detecting means for detecting a musical tone produced by the instrument and producing a signal corresponding to the tone, a processing means coupled with the medium of detection to compare the signal with a reference heat associated with the desired frequency and to produce an electrical control signal, the electric control signal is a function of the difference between the signal and the reference frequency value; string adjustment coupled with the processing means and with a plurality of strings associated with the string musical instrument, for selectively adjusting the tension of the plurality of strings depending on the electrical control signal, and the string adjusting means includes: at least one electric motor that responds to the electrical control signal, a transition medium associated with the plu of strings to selectively adjust the tension in each body

Description

"AUTOMATIC TUNER INSTRUMENT TUNER" BACKGROUND FIELD OF THE INVENTION The present invention relates to a tuning apparatus for musical string instruments. More specifically, the present invention relates to a tuning apparatus that responds to the frequency, capable of adjusting the pitch or tuning of the instrument.

DESCRIPTION OF THE RELATED TECHNIQUE The tuning of musical string instruments typically requires a skilled musician or technician who exercises a string or strings of the instrument, listens to the sound of the note or string and if necessary adjusts the tension in the string or strings to tune the instrument. This procedure is delayed and typically can not be done during a function. To decrease the time needed to tune a string instrument, as well as to be able to allow novice or non-expert musicians to properly tune string instruments, tuning devices have been developed that adjust the tension in the strings. However, it is a problem to precisely control the tension of the string to produce the correct vibration frequencies. With string instruments, thumb screws and tuning bolts are commonly used to adjust the tension of the string to fine-tune the instrument. The initial adjustment to obtain an accurate string tension is a very tedious task for each performer. When new strings are installed in the instrument, a performer must first tighten and re-tension each string until its resilience is stabilized. With stable string resilience, the performer must now continuously adjust and readjust the tensions of the string until the resilience of the instrument's materials is stabilized relative to the force produced by the strings when properly tensioned, to produce the desired frequencies. During a function, the strings are frequently out of tune because the instrument is played continuously, temperature factors and natural sliding of the string during tension and re-tension. As will be seen, attempts have been made to provide string tuning devices that minimize the difficulties associated with manual tuning of a string instrument. For example, U.S. Patent No. 5,038,657 issued to Busley, relates to a rope tensioning apparatus having a bidirectional motor for controlling the tension of each chord and associated control electronics for regulating the operation of the rope tensioning apparatus. Each string is directly connected to the arrow of the motor whose rotation is regulated by associated control electronics. A transducer is used to measure the operating frequency of each string. The measured frequency is then compared to a value stored in the memory, to produce an indication of the difference between the current and desired operating frequency. This difference is then used to control the direction and amount of rotation of the motor shaft in order to adjust the frequency of the strings. Manual switches are placed on the body of the instrument to activate the motors and to tune the instrument. However, the use of multiple motors inside the instrument and the use of switches placed in the body of the instrument, increases the weight of the instrument making the instrument annoying for a performer. As another example, U.S. Patent No. 4,375,180 issued to Scholz relates to a string musical instrument with an automatic self-tuning device that tightens or loosens the strings of the instrument that may be out of tune. Each string is provided with an independent automatic tuning device and all devices are operated simultaneously, upon request, in order to automatically readjust the tension of the strings. Each tuning device detects the tension of its associated string and compares the detected voltage with a reference voltage corresponding to the desired tuning for the string. The tension of the rope is then increased or decreased in response to the nature and magnitude of the comparison of the tensions of the rope.

COMPENDIUM OF THE INVENTION The present invention relates to an apparatus for tuning the musical strings of a string musical instrument at a predetermined frequency selected by the user. In a preferred embodiment, the tuning apparatus of the present invention includes a detection means for detecting a musical tone produced by a musical string of the string musical instrument. The detection means works to produce a signal corresponding to the detected musical tone of the musical string when excited by the user. Preferably, the detection means includes pickup sensors placed below the musical strings of the musical instrument. Signal conditioning means are provided and coupled with the detection means to remove the predetermined signal harmonic from the detected musical tone. In addition, processing means are provided and coupled with the signal conditioning means for comparing the musical tone with a frequency value selected from the user. The processing means operates to produce an electrical control signal that is a function of the difference between the detected musical tone and the frequency value selected by the user. Preferably, the processing mode includes a central processing unit having an associated random access memory (RAM) and a read-only memory (ROM). The tuning apparatus responsive to the frequency of the present invention, in accordance with a preferred embodiment, includes a string adjustment means coupled with the processing means and with a plurality of musical strings of the string musical instrument. The string adjusting means works to selectively adjust the tension of a selected musical string, depending on the electrical control signal that was produced by the processing means. The string adjusting means includes an electric motor that responds to the electrical control signal of the processing means. The string-adjusting means further preferably includes a plurality of gear sets, each associated with a musical string of the string musical instrument. A clutch mechanism is further included which is operatively associated with each of the plurality of gears, with the clutch mechanism being capable of operating to selectively engage a gear assembly with the electric motor in order to selectively tune to a selected musical string with a frequency value selected by the user.

BRIEF DESCRIPTION OF THE DRAWINGS The various embodiments of the apparatus of the present invention will now be described, with reference to the drawings, in which: Figure 1 is a perspective view of the signal conditioner and the motor controller; Figure 2 is a functional diagram of the tuning portion of the apparatus of the present invention shown in Figure 1; Figure 3 is a schematic functional diagram of the circuit of the tuning apparatus of Figure 2; Figure 4 is a top plan view of the string instrument, illustrating an inner portion having a string adjusting mechanism; Figure 5 is a partial cross section of the string instrument illustrating a string adjusting mechanism of Figure 4; Figure 6 is an alternative embodiment of the string adjusting mechanism, adapted to drive the arrows in the body of the string instruments; and Figure 7 is a top plan view of a portion of a string instrument, illustrating multiple drive motors for tensioning the strings of the instrument.

DETAILED DESCRIPTION Referring now in specific detail to the drawings, wherein the like reference numbers identify similar or identical elements, Figure 1 illustrates a body portion 100 of the tuner apparatus 150, electrically coupled with a guitar 10 in accordance with a preferred embodiment of the present invention. It should be appreciated that the tuning apparatus 150 of the present invention is configured to be used in string instruments and for exemplary and exemplary purposes, the tuning apparatus 150 will be described below with respect to a preferred embodiment consisting of an electric guitar. However, the tuning apparatus can be deployed to any of the various string instruments such as acoustic guitars, cellos, violins and pianos. Furthermore, it should be understood that the electric guitar 10, as referenced thereto, includes a body portion 14 having a bridge assembly 16 for supporting the strings 18 of the guitar, and a portion 20 of neck extending from portion 14 of the body. As is conventional, the electric guitar 10 includes the provision of musical pickup sensors 24 preferably positioned below and in proximity to the strings 18 of the guitar, in order to detect the harmonic frequency of each string 18 of the guitar.

With reference to Figure 2, a functional diagram of the tuning apparatus, generally designated 150, is illustrated. The tuning apparatus 150 includes a signal conditioning unit 160 that functions to receive the harmonic signals from the pickup sensors 24. of the aforementioned instrument. The signal conditioning unit 160 further functions to filter the input harmonic signals received from the pickup sensors 24 of the instrument and modify the aforementioned signals in order to be in condition for a subsequent comparison and with a frequency selected by the user, as determined by the frequency adjustment unit 102, in order to determine if the harmonic input signals from the guitar 10, through the pick-up sensors 24 have been properly tuned, as will be described further below. The frequency adjustment unit 172 is coupled to the signal conditioning unit 160 wherein the frequency adjustment unit 162 operates to allow a user to selectively determine the appropriate frequency value mentioned above, through the adjustment switches 110 of frequency (Figure 1). The tuning apparatus 150 further includes a string adjusting controller 164 and a string adjusting mechanism 168. The string adjusting controller 164 is preferably contained in the outer body portion 100 and electrically coupled thereto with the signal conditioning unit 160. The string adjustment controller 164 is operatively associated with the guitar strings 18 through the string adjustment mechanism 168, the functionality and configuration of which will be described further below. the string adjusting controller 164 receives the aforementioned modified input harmonic signals from the signal conditioning unit 160, and functions to generate electrical control signals and transfer the electrical control signals to the string adjusting mechanism 168, which adjusts the string 18 of the guitar appropriate to the frequency selected by the user, as will be discussed further below. In particular, and as will also be discussed further below, the aforementioned electrical control signal generated from the string adjusting controller 164 is a function of the difference between the current frequency value of a selected guitar string 18, as shown in FIG. detected by the pickup sensors 24, and the desired frequency value as selected by the user through the frequency adjustment unit 162, through the frequency adjustment switch 110. In the preferred embodiment of the tuning apparatus 150, the signal conditioning unit 160 described above, such as the frequency adjustment unit 162 and the string adjustment controller 164, are contained in the body 100, placed outside the body 14. of the guitar, as shown in Figure 1. However, it should be appreciated that the aforementioned components of the tuning apparatus can be placed internally within the body 13 of the guitar. Referring now to Figure 3, a functional diagram of the signal conditioning unit 160, the string-adjusting controller 164 and the string-adjusting mechanism 168 is illustrated. As shown, the string adjustment controller 164 includes a processor 170, such as the Basic Stamp microprocessor, manufactured by Parallax Inc. The above-mentioned processor 170 preferably includes a random access memory (RAM) 172 and a memory only reading (ROM) 175. The system and application programs are stored in the memory to control, for example, the operation of the tuning apparatus 150 of the present invention. As with these memory configurations, the memory decoders 116 are used being configured to focus the specific memory from the RAM 172 and ROM 175. The input / output (I / O) decoders 174 are used to properly regulate the input and output data flow of the 160 conditioning unit signals. The signal conditioning unit 160 includes a filter network 176 which functions to receive signals from the pickup sensors 24 (Figure 1) and subsequently filter the signals mentioned above to isolate the desired frequency for subsequent processing. The filtered signals are then preferably converted into a digital format by means of an analog-to-digital (A / D) converter 178. The digital signals of the A / D converter 178 are then attenuated by the buffer 180 and transferred to the processor 170. In the present preferred embodiment, as shown in FIG. 1 and as mentioned above, the adjustment switch 110 frequency is provided in the body portion 100 which is coupled to the frequency adjustment unit 162. The frequency adjustment switch 110 is configured to be selectively operated by the user in order to adjust a string 18 of the preselected guitar to a predetermined harmonic frequency value. Referring to Figure 3, the data of the aforementioned frequency adjustment switch 110 and the adjustment unit 162 are latched by the latch 182 and transferred to the processor 170 for comparison with the data received from the pickup sensors 24 . The portion 100 of the body preferably includes the provision of presentation means 112 configured to present selected frequency settings as well as the frequency of the data received from the pickup sensors 24. Continuing the references to Figures 1 to 3, the use of the tuning apparatus 150 of the present invention will now be discussed. It will be appreciated that the preferred embodiments of the string adjusting mechanism 168 will be described further below. First, the user determines which string 18 of the guitar of the guitar 10 will be tuned appropriately, through the guitar switches 152, which are provided in the body portion 100 as well as the selected frequency value where the string 18 of the aforementioned guitar through manipulation of the frequency adjustment switch 110 that is provided in the body portion 100 of the tuner apparatus. The user then, through a preferred manual manipulation, excites the string 18 of the aforementioned selected guitar so that the pickup sensor 24 preferably generates an analog oscillatory signal (voltage) having a fundamental frequency value that depends on, among other factors, the length of the string 18 of the guitar, its cross section, material and tension. As is known for any given guitar string 18 by increasing its string tension, its fundamental frequency of oscillation increases. After the aforementioned oscillatory signal is received from the pickup sensors 24, the last signal is the signal conditioned in the signal conditioning unit 160 such that the unwanted portions of the received signal, such as a frequency spectrum unwanted, it is removed from it allowing a signal that is proportional to the oscillation frequency of the string 18 of the guitar to be retained. Once the oscillation frequency for a selected guitar string 18 is obtained, the string adjustment controller 164 operates to compare the above-mentioned desired frequency of reference with the above-mentioned measured frequency, and preferably through an algorithm of control, the difference between the frequencies (the desired frequency and the measured frequency) is processed to calculate the necessary electrical control signal that drives the motor (as will be discussed below), which is able to work to tune the strings 18 of the guitar. It will be appreciated that the aforementioned process can be carried out either in an analog or digital format, continuous until the error signal (i.e., the difference between the desired frequency and the measured frequency) falls within a predetermined scale of the value of desired frequency. In particular, the aforementioned control signal operates in such a way that if the measured frequency is less than the desired frequency, it will rotate the motor in the direction that increases the tension in the string of the selected guitar up to an amount proportional to the difference between the desired and measured frequencies. The tuning apparatus of the present invention operates in the manner described above until the string 18 of the excited pre-selected guitar is taut within a prescribed acceptable range of the desired frequency value. In the present preferred embodiment, a light 114 is provided in the body portion 100 and functions to illuminate when the desired tuning has been achieved for a chord 18 of the selected guitar. Referring now to FIGS. 4 and 5, a preferred embodiment of the aforementioned internal string adjusting mechanism 168 is shown which is capable of operating to adjust the tension of the guitar strings 18 on an electric guitar. The internal string adjustment mechanism 168, as illustrated in the preferred embodiment of Figures 4 and 5, is mounted on the inner body portion of the guitar 14. In the preferred embodiment illustrated, the string adjustment mechanism 168 includes a gear train 200 operably coupled with a drive motor 202. The gear train 200 is preferably a series of gears 210a-f, wherein a single gear 210f at one end of the gear train 200 couples the drive motor 202. Preferably, the number of gears 210a-f is defined by the number of strings 18 of the guitar that are provided in the guitar 10. For example, in the preferred embodiment as shown in Figure 4, there are 5 strings 18a-e of guitar provided on the guitar 10 and 6 gears 210a-f, a gear 200a-e respectively for each string 18a-e of the guitar, and a gear 210f which is dedicated for the driving motor 202. Each gear 210a-e operates to respectively adjust the tension on each guitar string 18a-e, of the guitar 10. Each 210a-e gear associated with a respective guitar string 18a-e on the guitar 10, is coupled with a bearing 212a-e secured in the portion 14 of the body of the guitar, and a clutch assembly 214a-e selectively actuated. Each clutch assembly 214a-e functions to engage a respective gear 210a-e with the drive motor 202. Each clutch assembly 214a-e can be actuated mechanically, for example, by moving a lever (not shown). Preferably, each clutch assembly 214a-e is an electrically or magnetically driven assembly that responds to the control signals that are provided by the aforesaid string-adjusting controller 164. Further, each respective clutch assembly 214a-e, when activated by the string adjusting controller 164, functions to interconnect an arrow 217a-e string adjusting drive with its corresponding engagement 210a-e, the functionality of which will be discussed then. Referring now to Figure 5, with continuous reference to Figure 4, each string-adjusting arrow 216a-e engages, screw-tightly with a first end of a respective lever mechanism 218a-e, which is pivotally connected to the portion 14 of the body of the guitar around a respective hinge member 220a-e connected thereto. A guitar string 18a-e is respectively connected to a second extrusion of a lever mechanism 218a-e, such that the proximal movement of the second end of the lever mechanism 18a-e towards the string holder 22, effects the loosening of a respective guitar string 18a-e, while the distant movement of the second end of the lever mechanism 218a-e remote from the string support 22, effects the tightening of a respective guitar string 18a-e. Accordingly, the rotational movement of a string adjusting screw 216a-e effects the proximal movement of a second end of a respective lever mechanism 218a-e towards the rope holder 22, while the rotational movement of a screw 216a-e of string adjustment effects the remote movement of a second end of the respective lever mechanism 218a-e away from the rope holder 22. During use, the string adjustment mechanism 168 (Figure 2) generates an electrical control signal that activates the clutch assembly 214a-e (Figure 4), associated with the guitar string 18a-e selected to tune to a frequency desired, as described above. For example, if the string 18c of the guitar is selected to be tuned to a desired frequency, the control signal generated from the string adjusting controller 164 activates this clutch assembly 214c. The aforementioned control signal further causes the driving motor 202 to rotate in a direction, which correspondingly effects that the string adjusting screw 216c rotates either in a first direction to the right or second to the left, causing the string 18c of the guitar is loosened or tightened to place the string 18c of the guitar up to a permissible scale of the desired frequency value selected by the user, as detected by the pickup sensors 24 and as described above. Another preferred embodiment of the rope adjustment mechanism 168 is illustrated in Figure 6, which illustrates the head region 26 of the neck portion 20 of the guitar 10. In particular, the head region 26 is provided with worm gear assemblies. 28a-e respectively. It will be appreciated that the specific configuration of this worm gear assembly is well known in the art and need not be described here. Functionally connected with each worm gear assembly 28a-e there is an elongated drive arrow 30a-e, respectively. The rotation of the elongated driving arrow 30a-e (i.e., a tuning bolt of a guitar) in a first right-hand direction causes a corresponding worm gear assembly 28a-c to loosen a rope 18a-e from the corresponding guitar, while the rotation of the arrow 30a-e elongated in a second left-hand direction, causes a corresponding worm gear assembly 28a-e to tighten a corresponding string 18a-e of the guitar. In the preferred embodiment illustrated of Figure 6, each elongated arrow 30a-e is formed to have a hexagonal configuration to allow detachable coupling with a drive motor, as will be discussed further below. However, it will be appreciated that the hexagonal configuration is only one of many configurations that can be employed to allow the aforementioned detachable coupling. For example, coupling devices such as splines, square-shaped arrows and various types of screw head can be employed to allow the aforementioned detachable coupling between the driving motor 220 and an elongated shaft 30a-e. An impeller motor 220 is electrically coupled to the body portion 100 of the tuning apparatus 150 of the present invention (Figure 1), whereby the drive motor 220 is provided with a head portion 222 configured for detachable coupling mentioned above with the end portion of an elongated driving 30a-e arrow. Preferably, in the preferred embodiment of Figure 6, the head portion 222 is a hexagonal configuration, but is not limited thereto., as mentioned above. During use, the user manually couples the head portion 222 of the driving motor 222 with an elongated drive arrow 30a-e which is respectively associated with a guitar string 18a-c that the user wishes to tune to a selected frequency value. . After the user has selected the desired frequency and excited the string 18a-e of the guitar, which is to be tuned as mentioned above, the string adjustment controller 164 generates an electrical control signal which causes the drive motor 220 rotates in a direction that makes it corresponding that a coupled elongated driving arrow 30a-e rotates either in the first direction to the right or second direction to the left, causing the coupled worm gear assembly 28a-e to loosen or tighten the selected guitar string 18a-e so that it is tensioned so that it vibrates within a permissible range of the user's selected frequency value. The user can repeat the aforementioned process with respect to another string 18a-e of the guitar in order to properly tune that string 18a-e of the selected guitar up to a selected frequency value. Still another embodiment of the rope adjustment mechanism 168 is illustrated in Figure 7. This embodiment is essentially similar to the embodiment of the rope mechanism illustrated in Figure 6 with the exception that the body portion 100 of the tuning apparatus and more particularly, the rope adjusting controller 164 is electrically coupled to the 230a-and impeller motors. The driving motors 230a-e are provided as a respective head portion 232a-e which is configured to detachably couple the end portion 31a-c of each respective elongated arrow 30a-e, as shown in Figure 7. Furthermore, as mentioned above, the body portion 100, the tuning apparatus 150 is provided with motor drivers switches 152 which operate to drive a respective driving motor 230a-e when activated. During use, the user first activates the drive motor switch 152 which corresponds to the a-e string of the guitar, which he wishes to tune to the user. The user then selects a desired frequency for the string 18a-e of the selected guitar and after which the user excites the selected guitar string a-e. As described above, the string adjusting controller 164 generates an electrical control signal that functions to rotate the driving motor 230a-e corresponding to the selected guitar string 18a-e in a direction to properly tune the string 18 of guitar selected to be within the desired frequency scale.

Alternatively, the body portion 100 of the tuning apparatus 150 will contain sufficient electronics and hardware to simultaneously tune each string 18a-e. For example, the tuning apparatus 150 of Figure 2 may have five separate signal conditioning units 160, string adjusting controllers 164 and string adjustment mechanism 168, each configured as a separate tuning apparatus 150. Each separate tuning apparatus 150 would have a single instrument pickup sensor 24 for a specific string 18a-e and the frequency selected by the user for each string would be determined by one of five frequency settings 162 dedicated to string 18a-e specific. Therefore, all five strings 18a-e would be tuned, simultaneously, by the five separate tuning apparatuses 150. Alternatively, a single string adjusting controller 164 will be addressed to the five separate signal conditioning units 160 and to the five separate string adjustment mechanisms 168. Each signal conditioning unit 160 would receive an input from one of the five instrument pickup sensors 24 and process it for the string adjusting controller 164. Therefore, the modified input harmonic signal from each signal conditioning unit 160 will correspond to a specific guitar string 18a-e. The frequency setting 162 related to the specific signal conditioning unit 160 for a specific chord 18a-e would be fixed, and would be eliminated from the frequency adjustment switch 110 (of Figure 1). The output of the string adjusting controller 164 for the specific signal conditioning unit 160 would be sent to the string adjusting mechanism 168 corresponding to the same string. Assuming that the processor 170 (see Figure 3) has sufficient capacity to handle the processing of the five strings 18a-e simultaneously (or in a multiplexing process) all five strings 18a-e could be adjusted simultaneously. Even though the invention has been shown and described with particularity by reference to certain specific embodiments, it will be understood by those skilled in the art that various modifications to the form and details may be made therein without departing from the scope and spirit of the invention. Accordingly, the modification or preferred embodiments will be readily apparent to those skilled in the art and the generic principles defined herein may be applied to other embodiments without departing from the spirit and scope of the invention. In this way, the present invention is not intended to be limited to the modalities shown, but can be provided with the broadest scope compatible with the principles and particularities disclosed herein.

Claims (20)

R E I V I N D I C A C I O N S

1. An apparatus for tuning a string musical instrument, the apparatus comprises: a detecting means for detecting a musical tone produced by the instrument and producing a signal corresponding to the tone; a processing means coupled with the detection means for comparing the signal with a reference value associated with the desired frequency and for producing an electrical control signal, the electrical control signal is a function of the difference between the signal and the value of reference frequency; and a string adjusting means coupled with the processing means and with a plurality of strings associated with the string musical instrument, to selectively adjust the tension of the plurality of strings depending on the electrical control signal, and the adjustment means Strings include: at least one electric motor that responds to the electrical control signal; a transition means associated with the plurality of strings to selectively adjust the tension of each string.

2. An apparatus for tuning a string musical instrument according to claim 1, wherein the transition means further includes a clutch mechanism for selectively adjusting the tension of each string.

An apparatus for tuning a stringed musical instrument according to claim 1, wherein the detecting means includes musical pick-up sensors positioned in proximity to the plurality of strings in the string musical instrument.

4. An apparatus for tuning a stringed musical instrument according to claim 3, wherein the musical pick-up sensors include at least one microphone.

An apparatus for tuning a string musical instrument according to claim 1, further including a signal conditioning means coupled with the detection means for removing the signal harmonics of the predetermined signal.

6. An apparatus for tuning a stringed musical instrument according to claim 5, wherein the signal conditioning means includes an analog to digital connverter for converting the signal from an analog signal to a digital signal.

7. An apparatus for tuning a string musical instrument according to claim 1, wherein the processing means includes a central processing unit having an associated random access memory and a read-only memory.

An apparatus for tuning a stringed musical instrument according to claim 2, wherein the transition means further includes a plurality of lever mechanisms operably connected with each string respectively such that they are determinative of the tension of a string connected operably with the pivot lever mechanism.

9. An apparatus for tuning a string musical instrument, the apparatus comprising: a detecting means for detecting a musical tone produced by the instrument and for producing a signal corresponding to the tone, the detection means includes: a coupled processing means With the signal conditioning means for comparing the signal with a reference value and producing an electrical control signal, the electric control signal is a function of the difference between the signal and the reference value, the processing means includes: a string adjusting means coupled with the processing means and with a plurality of strings associated with the string musical instrument, in order to selectively adjust the tension of the plurality of strings, depending on the electrical control signal, the String adjustment includes: (i) at least one electric motor that responds to the electrical signal; (ii) a plurality of gears with each gear being operatively associated with the rope respectively; and (iii) a clutch mechanism operatively associated with the plurality of gears for selectively coupling the gear with the electric motor.

An apparatus for tuning a stringed musical instrument according to claim 9, further including a signal conditioning means coupled with the detection means for removing the signal harmonic signaled from the signal, including the conditioning means of signals a filter network.

11. An apparatus for tuning a string musical instrument according to claim 9, wherein the string adjusting means further includes a plurality of driving arrows, each driving shaft is operably connected to a gear, respectively.

12. An apparatus for tuning a string musical instrument according to claim 11, wherein the string adjusting means further includes a plurality of lever mechanism, each lever mechanism is operably connected to the string respectively, and each mechanism The lever is rotatably connected to the driving arrow respectively in such a way that the direction of rotation of the driving shaft is determinative of the tension of the rope.

13. An apparatus for tuning a string musical instrument according to claim 9, wherein the detection means includes musical pickup sensors positioned in proximity to the plurality of strings.

14. An apparatus for tuning a string musical instrument according to claim 9, further comprising a frequency adjustment means coupled with the processing means and operating to enable a user to selectively select the predetermined frequency value.

15. An apparatus placed outside of a musical instrument for tuning the string musical instrument, the apparatus comprises: a detecting means for detecting a musical tone produced by the instrument and for producing a signal corresponding to the tone; a processing means coupled with the detection means for comparing the signal with a reference value associated with the desired frequency and producing an electrical control signal, the electrical control signal is a function of the difference between the signal and the value of reference; and a string adjusting means coupled with the processing means and a plurality of strings associated with the string musical instrument for selectively adjusting the tension of each string depending on the electrical control signal, the string adjusting means includes: ( i) at least one electric motor that responds to the electrical signal and at least one electric motor that is fixedly mounted to the outside of the string musical instrument; and (ii) a coupling means for releasably coupling at least one electric motor with the string of the musical instrument.

16. An apparatus placed to the outside of the musical instrument for tuning the string musical instrument according to claim 15, further including a plurality of electric motors positioned to the outside of the musical instrument, wherein the coupling means is adapted to detachably couple the plurality of electric motors with the plurality of strings.

17. An apparatus for positioning to the outside of the musical instrument for tuning the string musical instrument according to claim 16, wherein the plurality of electric motors is fixedly attached to the plurality of strings.

18. An apparatus for tuning a stringed musical instrument according to claim 15, wherein the detection means includes musical training strings positioned in proximity to the plurality of strings of the stringed musical instrument.

19. An apparatus placed to the outside of the musical instrument for tuning the musical instrument according to claim 18, wherein the musical pick-up sensors include at least one microphone.

20. An apparatus for tuning a stringed musical instrument according to claim 14, wherein the processing means includes a central processing unit having an associated random access memory and a read-only memory.