Device and method for automatically tuning a stringed instrument, particularly a guitar

Translation of description of equivalent WO 2005116986 A1

Apparatus and method for automatic tuning of a string instrument, particularly a guitar

The present invention relates to a device for automatic tuning of a string instrument according to the preamble of claim 1. It further relates to a method for automatic tuning of a string instrument according to the preamble of claim 11.

The voices of instruments generally requires next to a trained ear a lot of time, which must be applied in particular by inexperienced, for example amateur instrumentalists.. In the classical method of tuning "manually" the musician works with a tuning fork, which sets and adjusts by changing the string length or string tension the desired sound by hitting the pitch of each string. Through Multiple uses of the string and the tuning fork is the result adjusted until the desired tuning of the string is reached. Based on this mood the other strings are then tuned.

As a part regularly voted the strings of instruments because of ever-present resilience of the material must be the strings of the climatic conditions in their length varies others are partly dependent on (a guitar string extends to the stage of a concert hall with the heat and humid air compared to the conditions in the relatively dry and cool practice room from), is a common votes required. Even after the installation of new strings, these need to be tuned.

In order to provide a relief here, a device for automatic tuning of a string instrument has been proposed in US 4,803,908, which comprises all features of the preamble of claim 1. In this device, all strings are struck simultaneously on a guitar with a there "Strummer" mentioned, arranged in the body of the guitar aids. An electronics detects the tones, comparing them to the desired setting and controls an attacking on the strings adjusting device for adjusting the string tension that they meet in the manner prescribed tones on.

The system is so far very welcome, as it allows a rapid and automatic voices and so especially untrained musicians, but also the professionals decreases a great deal of effort. However, the system has a significant disadvantage. It is generally large and bulky and will require significant changes in the body of the guitar, on the one hand an influence on the acoustic (sound) and the other hand on their handling (because of the changing weight) have. Apart from the appearance of the guitar is changed in a significant manner.

Since the entire guitar is the decisive for the sound characteristics of sound, also the sound characteristics change when it is changed. In order the prior art system in existing instruments almost can not be retrofitted, but it can also be difficult to integrate into new guitars. In particular, two types of guitars were aurally in planning to develop independently, a guitar with the known device and one without.

From the problems described, the invention is based. Its task is to provide a far improved device that can be integrated into an instrument, in particular a guitar with minimal impact on the sound quality and with as few and small elements. Furthermore, a method for automatic tuning of a string instrument is to be provided which satisfies these requirements.

To achieve this object a device having the characteristics of claim 1 is proposed. A method which solves this problem is given in claim 11th

Claims 2 to 10 and 12 to 15 contain advantageous developments of the device or process.

The core idea of ​​the invention is to supply at least parts of components of the device, the required voltage supply via one or more of the strings. These strings are designed conductive, they consist of either a conductive material or with such a wound and / or coated. In this way, for example. In a guitar, in particular an electric guitar components thereof are arranged on the head without addition there is a power supply must be integrated (eg. In the form of a battery or own supply terminal). The power supply can in this example, over the are supplied to the guitar body, and further via the one or more guitar string (s) to the head.

In this way, it is possible to save space and weight is either less space on such a portion of the instrument which is on one longitudinal end of the strings on which or what little weight can withstand, to arrange at least some of the components of the apparatus.

According to claim 2, the components of the device (which may be referred to as also seen as a system) distributed on the instrument, and a bus line bridges the distance along the length of the strings. In a guitar, for example., The entire device is not arranged in the corpus. So has the head and neck also, albeit only slightly, space for (discreet) attachment of other components. In particular may be achieved in any case arranged on the head at guitars means for adjusting the string length or - fall back voltage, the use of spe- alteilen reduced. Overall, the guitar, fewer additional components, in the instrument, for example. Are introduced.

The signal transmission via the bus line can, for example, via a conventional bus cable, but also wireless, for example. Via radio or infrared, take place.

To separate the components of the controller and drive, however, be able to make in the instrument body without profound interventions, the control signals between the seated at an instrument portion control and the at least one drive after a development of the invention preferably via the serving as bus lines strings (claim 3). The strings of stringed instruments consist in many cases of a conductive material (metal) or are wrapped by a thread from such. Alternatively, they may, when the sound permits, be coated with a conductive material. This solution saves the use of more lines that have to be transferred to the instrument body. In addition to sound quality, therefore, the appearance of the instrument is maintained not last. Thus, if several strings are to be used as a conductor, these are not mutually electrically shorted, have elements over which the strings are common (eg. The ridge on a guitar) be designed so that they insulate the strings up to today. For this purpose, these elements can be made of a nonconductive material (eg. Ceramics) manufactured or coated with such, or there must be other arrangements of the insulation to be taken (eg. Intermediate insulating disks etc.).

The drive can be a motor, for example. Electric motor, but it can also operate pneumatically or hydraulically.

If the instrument connected by electrical means to an amplifier instrument (z. B. an electric guitar), so can an already existing and connected to the amplifier pickups of the instrument can be used as (part of) detection unit.

A specified in claim 4 configuration of the controller, this can be addressed simply by hitting one side.

An interface, as may be provided in accordance with claim 5, is the possibility of outside - even retrospectively - to supply a software in the device. Furthermore, different reference tunings can be entered into the storage device via the interface to tune the instrument to different schemes can. A proposed in claim 6 design of the device allows a stringed wise tune the instrument. It can equally well be used a drive which can be switched by appropriate gear or similar devices for moving each of a string.

Is the device as specified in claim 7 which results in a particularly compact design. If the individual components as small as possible, "disappear" they do not the same almost in the overall impression of the instrument and interfere with the musicians at play. In addition, there is no need to consult external components when tuning the instrument, the musician may be instrument virtually anywhere and virtually independent vote.

A development of the device according to claim 8 results in a redundant system. The apparatus may be further operated at a defect string to tune the instrument.

In the claims 9 and 10, a preferred embodiment of the device for integration in an electric guitar is indicated in each case.

The method according to claim 11 is as already said above a solution of the above-mentioned object relating to a method. It can be operated preferably with a device according to one of claims 1 to 10, but is not limited to such a device.

Claim 13 describes, as preferred, the strings of the instrument can be used as bus lines. This need no separate cables or other transmission medium (radio, infrared) are installed. A required as in a development of the method according to claim 14 processing the first digital signal may be useful in order to reliably determine from this signal, a pitch can.

A determination of the fundamental frequency (pitch) of the first digital signal is preferably carried out with the aid of a mathematical frequency filter (claim 15). This allows, in contrast to the otherwise customary method of the Fast Fourier Transformation (FFT), a faster and more accurate frequency determination from only a stop of the string. This is important because the overtones that must be collected for a precise determination of the pitch (frequency) decay with only one stop of the string, very fast.

In the following the invention will be briefly described with reference to the accompanying figures. Show it:

Fig. 1 is a schematic front view of an electric guitar as a possible application of the invention,

Fig. 2 is a schematic view of the guitar of Fig. 1, from the rear

FIG. 3 is another schematic view of the electric guitar with other details,

Fig. 4 is an enlarged view of the body of the electric guitar according to the representation in Fig. 3,

Fig. 5 in four different representations (a) to (d) a rider of the tremolo system block of the electric guitar,

schematically nungsversorgungs- Fig. 6, the attachment of the strings in the tremolo system block and their contact with the voltage or signal lines, Fig. 7 in four different views (a) to (d) the head of the guitar with attached wings and positioning motors for adjusting the string tension,

Fig. 8 in four different views, the person sitting in the head of the guitar Batwing with servomotors and

Fig. 9 is a schematic circuit diagram of a detector circuit for controlling a T-power for the device for automatic tuning of the guitar.

In the figures, the invention based on an embodiment with an electric guitar is explained in detail. The same elements are provided in the figures with the same reference numerals. The description on the basis of an electric guitar does not limit the invention. It can be used equally well with acoustic guitars, E- bass, or other electrical or electro-acoustic or acoustic stringed instruments such as violins, harps etc..

In Figures 1 to 4 an electric guitar 1 shown in different, partially enlarged views which is provided with a device according to the invention. The electric guitar 1 can be roughly divided into the body 2, the web 3 and the head 4. On body are on the so-called tremolo system block 5 the strings 6a - .beta.f secured with their first ends (ball ends) and next to each other on the Steg 3 stretched to the head 4, where they wound up with their second ends to vertebrae 7 and set adjustable. The pegs 7 are mechanically connected with wings 8, 8 so that the strings end up by turning the wing t on the pegs 7 or can be unwound therefrom. This causes the voltage and length of the string is changed and tuned the guitar. In Figure 1, a so-called pick guard is also seen 9, which is a kind of cover and under which a space is created in the body 2, is arranged in which the electronics of the electric guitar. 1 Below this pick-Guards 9 associated to a control chip of the device according to the invention is arranged, which is indicated in Fig. 2 schematically with 10.

In Fig. 2 further shows that the electric guitar 1 to the mechanics of the wings 8, eg. Via a gear, acting servo motors 11 are arranged on the head 4. The servomotors are part of the apparatus and are connected in Later still to be described way with the control chip 10 for driving. With the motors can be adjusted alternatively to the manual override on the flanks 8 eddy 7 rotated and thus the tension of the strings 6a-6f.

In FIGS. 3 and 4 is shown in a different presentation, the electric guitar. 1 Here are the next in Figs. 1 and 2 to be recognized elements shown further details of the electric guitar. 1 Thus, the occupant seated in the body 2 below the strings 6a to 6f pickup (pickups) are, for example, to detect the vibrations of the strings (and therefore the sound produced by striking the same) to convert into an electrical signal 12. These pickups 12 still serve at the same time in later manner to be explained as part of the inventive device.

Furthermore, in these representations, a potentiometer 13 is shown. Usually electric guitars have more than one such potentiometer to adjust the treble, bass and volume. Here the potentiometer shown is 13, the volume control. This particular controller is the integration of the inventive device in the electric guitar 1 not carried out as a conventional potentiometer, but as a so-called push-pull potentiometer which has an additional switching function.

Finally, the leading of the control chip to the tremolo system block 5, more precisely to the strings 6a to 6f lines 14 can be seen in these figures yet.

In FIGS. 5 and 6, the tremolo system block 5 and are shown arranged on this tab 15 for guiding the fixed in the tremolo system block 5 string ends. In FIG. 6, it can be seen how the strings 6a to 6f guided through bores 17 in the tremolo system block 15 and 18 are held at the bottom of the bores 17 arranged at their ends, thickenings (ball ends). In the lower end of the bores 17, an insulating sleeve 19 is respectively inserted, which is provided at its projecting out of the bore 17 with a rim outwardly facing collar. Between the collars of the sleeves 19 and the thick sections (ball ends) 18 are conductive plates 20 positioned, the 6a-6f contact the thick sections (ball ends) 18 of the strings. These disks are in turn connected to the connected to the control chip 10 lines 14 (shown here as 14a to 14f).

In this way, made of a conductive metal or wrapped with a conductive metal filament strings 6a-6f of the electric guitar 1 electrically connected to the control chip 10th

On the tremolo system block 5 are shown in Figs. 5 (a), to 5 (d) Rider 15 mounted. About this run in the tab inserts designated 16 pages. In FIG. 5 (d) enlarged tab is shown in use in FIG. 5 (a) shown in the rider in Fig. 5 (a) Recess shown on the right used. Since the tab 15 and the tab inserts 16 regularly made with an electric guitar 1 of metal and thus of a conductive material, in order to avoid a short circuit between the through lines 14 electrically contacted strings the rider inserts 16, over which the strings 6a 6f run, be insulated from each other. For this purpose, in FIG. 5 (a) are insulated with 21 designated areas.

In Figures 7 (a) to 7 (d) details of the head 4 of the electric guitar 1 are once again visible to the arranged thereon components of the device according to the invention, wherein Fig. 7 (d) shows an enlarged detail of FIG. 7 ( c) represents with D designated area.

In the figures 8 (a) to 8 (d) the mechanical units for adjusting the string tension consisting of the vertebrae 7, the wings 8 and the actuators 11 once detached from the head 4 are shown. It can be seen that all these units are on one common board 22 that contains additional controls for the servomotors 11th Via the metallic and thus conductive vertebrae 7, the strings are electrically connected to corresponding conductor paths on the circuit board 22nd

The inventive apparatus for automatic tuning of the electric guitar 1 operates as follows:

By pulling the push-pull potentiometer 13, the system is activated. For this purpose, recourse is made to a circuit shown in Figure 9, which will be hereinafter to be described.

The control chip 10 may be issued now by striking one of the strings commands. The sounds produced by striking the strings are represented by the pickup 12 in an electrical innovative signal changed, which is down converted in the controller to a frequency. In the control certain preprogrammed instructions are stored, which are called to a lying within a certain tolerance towards frequency. In this way, for example. The program for tuning one of the strings, the E-string 6f z. B. be called. If the program is activated, loads the control chip from a memory a reference frequency for that string, which serves as the target frequency. The string is then optionally struck again, calculates the actual frequency from the converted by the pickups 12 signal in the control chip 10 and a signal to the board 22 and through the latter to the corresponding servo motor 11 for adjusting the on used as bus lines strings string tension ball to reach the target frequency. In this case, the controller chip 10 monitors the change in frequency, and outputs a stop signal to the servo motor 11 upon reaching the target frequency this way, all the strings are tuned one by one. A routine for calculating the actual frequency from the electrical signal of the pickup, a mathematical frequency filter is used, since this can be particularly quickly and reliably calculate the frequency.

About a not illustrated in FIGS interface can be added to the control chip 10 different frequency values ​​for the strings, depending on what kind of mood is about to be selected (eg. Open tuning, etc.).

For the transmission of control signals, only two of the strings are needed. About two other strings, here the strings 6f (low E-string) and 6e (a string), the power supply for the board 22 and the servomotors spent 11 in the head 4, so that a separate power source is not needed there. The strings 6f and 6e are to over- carry the selected voltage as the deep e-string and the a string are the thickest strings of the electric guitar 1 and thus the least likely to tear. Of the remaining four strings 6a-6d any two of the control chip 10 arbitrary as bus lines can be freely controlled. In this way the system is redundant and can also, in one or even zwe work i broken strings the strings 6a-6d.

LEDs on the body 2, for example. In the field of pickups 12 underneath the strings 6a-6f can view the state of the control chip 10 or the program sequence and thus facilitate handling of the device. Also, here a "Quick Start Guide" to be applied, z. B. with the display, in which sound which commands by hitting which the strings 6a-6f. The commands assigned frequencies can be managed from the control chip 10 so that they are adapted to the current mood of the electric guitar, which means that the user must strike the same string with the same handle is always to get a command, no matter how the guitar and thus the string is just voted.

The power supply of the system is carried out in this embodiment externally and via the amplifier cable, with which the guitar is already electrically connected to an amplifier. The Tonaderschaltung illustrated in FIG. 9 constantly monitors the internal resistance of the electric guitar 1. This is high at normal play ready electric guitar 1. now attracts the musician the push-pull potentiometer 13, so the coupled from the pickups 12 of the jack for the amplifier cable and thus of the amplifiers and switches the control chip 10 to. Thereby, the internal resistance of the electric guitar 1 decreases by a factor of at least twentieth This recognizes the circuit and switches the amplifier cable to one of the Amplifier, so that the electric guitar 1 can be "silent" voted. Further on the circuit a supply voltage that they eg. From the power supply of the amplifier, but can also gain an external power supply to the amplifier cable. This voltage is then the controller 10 supplied and the strings 6e and 6f forwarded to the head 4. Now, the inventive device can work. After completion of tuning or eg. setting up circuit or the application of new data on the musicians on the push-pull potentiometer 13 back into the Normal position. the internal resistance of the electric guitar 1 increases by once again connected to the amplifier cable pickup 12 again. This recognizes the audio conductor circuit shown in FIG. 9 and outputs the signals from the amplifier cable back to the amplifier, the musician can continue playing.

LIST OF REFERENCE NUMBERS Guitar 21 surface body 22 board Stegskopf tremolo system block af string swirl vanes Pick Guard 0 controller chip 1 servomotor 2 pickups 3 Potentiometer 4 Line 5 riders 6 riders use 7 hole 8 9 thickening sleeve 0 disc