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

p0001The present invention relates to a device for automatic tuning of a string instrument according to the preamble of claim 1. It also relates to a method for automatically tuning a string instrument according to the preamble of claim 11.

p0002The tuning of instruments generally requires, in addition to a practiced hearing, a lot of time, which must be applied, in particular, by untrained, for example, hobby instrumentalists. In the classical method of tuning "by hand" the musician works with a tuning fork, which specifies the desired tone by striking and adjusts the pitch of the respective string by changing the string length or string tension. By repeatedly striking the string and the tuning fork, the result is adjusted until the desired tuning of the string is reached. Out of this mood, the other strings are tuned.

p0003Since the strings of the instruments have to be tuned on a regular basis, the strings of the strings are also variable in their length, depending on the climatic conditions (a guitar string stretches on the stage of a concert hall with the heat and humid air in comparison To the conditions in the comparatively dry and cool exercise room), a frequent tuning is required. They must also be tuned after the string has been wound.

p0004In order to create a relief here, <patcit id="pcit0001" dnum="WO03012774A"><text>WO 03/012774</text></patcit> As well as in the <patcit id="pcit0002" dnum="US4803908A"><text>US 4,803,908</text></patcit> A device for the automatic tuning of a string instrument, which has all the features of the preamble of claim 1. In this device, all the strings are simultaneously strung on a guitar with a strumming device arranged there in the body of the guitar. An electronics detects the tones, compares them with the desired setting, and controls a setting device acting on the strings for adjusting the string voltages in such a way that they meet the predetermined tones.

p0005To record the sounds continue to be in the documents <patcit id="pcit0003" dnum="US6278047B"><text>US 6,278,047</text></patcit> and <patcit id="pcit0004" dnum="US4318327A"><text>U.S. 4,318,327</text></patcit> Some devices for automatic tuning are disclosed, the conductivity of the strings being used for data acquisition in the sense of a measuring method by means of electrical contacts or oscillations.

p0006The system is very welcome to the extent that it allows for fast and automatic tuning, thus reducing the amount of effort required by untrained musicians as well as the professionals. However, the system has a not inconsiderable disadvantage. It is generally large and bulky and requires considerable changes to the body of the guitar, which in turn have an influence on their acoustics (sound) and on the other hand their handling (because of the changed weight). Apart from this, the visual appearance of the guitar is also changed in a not inconsiderable way.

p0007Since the entire guitar forms the resonant body which is decisive for the sound properties, the sound properties also change when this is changed. As a result, the previously known system can hardly be retrofitted into existing instruments, but it can also be difficult to integrate into new guitars. In particular, in terms of sound design, two types of guitars would be developed independent of each other, a guitar with the previously known device and one without.

p0008The invention is based on the described problem. She has the<b>Task,</b> To provide an improved device which can be integrated into an instrument, in particular a guitar, with minimal influencing of the sound properties and with as few and small elements as possible. Furthermore, a method for the automatic tuning of a string instrument which satisfies these specifications is to be specified.

p0009To the <b>solution</b> This object is achieved by a device having the features of the protective claim 1. A method which solves this object is specified in claim 11.

p0010Claims 2 to 10 and 12 to 15 contain advantageous further developments of the device or of the method.

p0011The core idea of ​​the invention is to supply at least the parts of the components of the device with the required voltage supply via one or more of the strings. For this purpose, the strings are designed to be conductive, they consist either of a conductive material or are wrapped and / or coated with such. In this way, for example, components can be arranged at the head of a guitar, in particular an electric guitar, without the need for a voltage supply (for example in the form of a battery or a separate supply connection). The voltage supply can in this example be fed via the body of the guitar and passed on to the head via the one or more guitar string (s).

p0012In this way, it is possible to arrange at least some of the components of the device on a portion of the instrument lying on a longitudinal end of the string on which there is either less space or which has little weight.

p0013According to claim 2, the components of the device (which may also be referred to as a system) are distributed on the instrument, and a bus line bridges the distance along the length of the strings. In the case of a guitar, for example, the entire device is not arranged in the body. Thus, the head or neck also provides, if only slightly, space, for the (discreet) attachment of further components. In particular, means for adjusting the string length or tension, which is arranged in any case for guitars on the head, can be used, which reduces the use of special parts. Altogether, fewer additional components have to be inserted into the instrument, for example the guitar.

p0014The signal transmission via the bus line can be effected, for example, via a conventional bus cable, but also wireless, for example via radio or infrared.

p0015In order to be able to make the separation of the component control and the drive, however, without profound interventions in the instrument body, the control signals are guided between the control unit sitting on one instrument part and the at least one drive preferably via the strings serving as bus lines 3). The strings of string instruments are in many cases made of a conductive material (metal) or are wrapped by a thread of one. Alternatively, if the sound allows it, they may be coated with a conductive material. This solution saves the use of additional cables which must be laid in the instrument body. In addition to the sound properties, the optics of the instrument are also retained. In order that when several strings are to be used as conductors, these are not electrically short-circuited, elements which are used to guide the strings together (for example, the bridge in the case of a guitar) must be designed in such a way that they isolate the strings from one another. For this purpose, these elements can be manufactured from a nonconductive material (for example ceramics) or coated with such a coating, or other measures of insulation (eg interposed insulating washers, etc.) must be taken.

p0016The drive can be a motor, for example an electric motor, but it can also operate pneumatically or hydraulically.

p0017If the instrument is an instrument electrically connected to an amplifier (eg an electric guitar), then an already existing pickup of the instrument already connected to the amplifier can be used as part of the recording unit.

p0018By means of a configuration of the control as indicated in claim 4, this can be addressed in a simple manner by striking a page.

p0019An interface, as may be provided according to claim 5, provides the possibility of feeding software into the device from the outside, even afterwards. Furthermore, different reference settings can be entered into the memory device via the interface in order to be able to match the instrument according to different schemes.

p0020An embodiment of the device as proposed in claim 6 permits a string-wise tuning of the instrument. It is also possible to use a drive which can be switched by means of corresponding gears or similar devices for adjusting one string in each case.

p0021If the device is formed as indicated in claim 7, a particularly compact design is obtained. If the individual components are selected to be as small as possible, they almost "disappear" in the overall impression of the instrument and do not disturb the musician in the same way. In addition, it is not necessary to add external components when the instrument is tuned, and the musician can tune his instrument virtually anywhere and almost independently.

p0022A further development of the device according to claim 8 results in a redundant system. The device can also be operated further for tuning the instrument even in case of a defect in a string.

p0023A preferred embodiment of the device for integration in an electric guitar is given in each case in claims 9 and 10.

p0024The method according to claim 11, as already mentioned above, represents a solution to the above-mentioned object with respect to a method. It can preferably be operated with a device according to one of claims 1 to 10 but is not limited to such a device.

p0025Claim 13 describes how preferably the strings of the instrument can be used as bus lines. This means that no separate cables or other means of transmission (radio, infrared) need to be installed.

p0026A processing of the first digital signal as required in a further development of the method according to claim 14 can be useful in order to reliably determine a sound position from this signal.

p0027The fundamental frequency (pitch) of the first digital signal is preferably determined with the aid of a mathematical frequency filter (claim 15). In contrast to the otherwise common method of Fast Fourier Transformation (FFT), this allows a faster and more precise frequency determination from only one stop of the string. This is important as the overtones, which must be recorded for an exact determination of the pitch (frequency), decay very quickly with only one stop of the string.

p0028The invention is briefly described below with reference to the appended figures. Show it:<dl id="dl0001"><dt>FIG</dt><dd>A schematic view from the front of an electric guitar as a possible application example of the invention,</dd><dt>FIG</dt><dd>A schematic view of the electric guitar <figref idrefs="f0001">FIG</figref> From behind,</dd><dt>FIG</dt><dd>A further schematic view of the electric guitar with other details,</dd><dt>FIG</dt><dd>An enlarged view of the body of the electric guitar as shown in FIG <figref idrefs="f0003">FIG</figref>,</dd><dt>FIG</dt><dd>In four different representations (a) to (d), a rider of the tremolo system block of the electric guitar,</dd><dt>FIG</dt><dd>Schematically the attachment of the strings in the tremolo system block as well as their contacting with the voltage supply or signal lines, </dd><dt>FIG</dt><dd>In four different views (a) to (d), the head of the guitar with wings attached thereto and servomotors for adjusting the string tension,</dd><dt>FIG</dt><dd>In four different views, the vane sitting in the head of the guitar with the servomotors and</dd><dt>FIG</dt><dd>A schematic circuit diagram of a detector circuit for activating a sound supply for the device for the automatic tuning of the guitar.</dd></dl>

p0029In the figures, the invention is explained in more detail with reference to an exemplary embodiment in the case of an electric guitar. Identical elements are provided with the same reference symbols in the figures. The invention is not limited to the use of an electric guitar. It can equally well be used with acoustic guitars, electric basses, or other electric or electroacoustic or acoustic stringed instruments such as violins, harps, etc.

p0030In the <figref idrefs="f0001 f0002 f0003 f0004">Figures 1 to 4</figref> An electric guitar 1 is shown in various, 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 bridge 3 and the head 4. On the body, the strings 6a-6f are fastened with their first ends (ball ends) to the so-called tremolo system block 5, Bar 3 to the head 4, where they are wound with their second ends on vertebrae 7 and adjustably fixed. The vortices 7 are mechanically connected to vanes 8, so that by turning the vane 8, the string end can be unwound or unwound from the vortex 7. This will change the tension or length of the string and the guitar will be tuned.

p0031In <figref idrefs="f0001">FIG</figref> A so-called pick guard 9 can be seen, which is a type of cover plate and under which a space is created in the body 2 in which the electronics of the electric guitar 1 are arranged. A control chip, which belongs to the device according to the invention, is arranged below this pickguard 9<figref idrefs="f0002">FIG</figref> Is indicated schematically with FIG.

p0032In <figref idrefs="f0002">FIG</figref> It can also be seen that on the head 4 of the electric guitar 1, arranged on the mechanism of the vanes 8, for example by means of a gearing, are arranged positioning motors 11. The servomotors are part of the device according to the invention and are connected to the control circuit 10 for activation in a manner to be described later. With the motors as an alternative to the manual actuation, the vortices 7 can be rotated via the vanes 8 and thus the tension of the strings 6a to 6f can be adjusted.

p0033In the <figref idrefs="f0003">FIG. 3</figref> and <figref idrefs="f0004">4</figref> The electric guitar 1 is shown in a different illustration. Here, in addition to the<figref idrefs="f0001">FIG. 1</figref> and <figref idrefs="f0002">2</figref> For further details of the electric guitar 1 are shown. Thus, for example, the pickups 12, which are arranged on the body 2 below the strings 6a to 6f, are able to convert the vibrations of the strings (and thus the sound produced by striking them) into an electrical signal. These pickup devices 12 serve at the same time as a component of the device according to the invention in a manner to be explained later.

p0034Furthermore, a potentiometer 13 is shown in these figures. As a rule, electric guitars have several potentiometers for adjusting the treble, bass and volume. Here the potentiometer 13 shown is the volume control. In order to integrate the device according to the invention into the electric guitar 1, this special controller is not designed as a conventional potentiometer but as a so-called push-pull potentiometer which has an additional switching function.

p0035Finally, the lines 14 leading from the control chip to the tremolo system block 5, more specifically to the strings 6a to 6f, can also be seen in these figures.

p0036In the <figref idrefs="f0005">FIG. 5</figref> and <figref idrefs="f0006">6</figref> The tremolo system block 5 or the tab 15 arranged on it is shown for guiding the string ends defined in the tremolo system block 5. In<figref idrefs="f0006">FIG</figref> It can be seen how the strings 6a to 6f are guided through bores 17 in the tremolo system block 15 and are held at the lower edge of the bores 17 with their ball ends 18 arranged at their ends. An insulating sleeve 19, which is provided at its edge protruding from the bore 17, is provided with an outwardly pointing collar in the lower end of the bores 17. Between the collars of the sleeves 19 and the ball ends 18, conductive discs 20 are positioned which contact the ball ends 18 of the strings 6a to 6f. These disks are in turn connected to the lines 14 (shown as 14a to 14f) connected to the control chip 10.

p0037In this way, the strings 6a to 6f of the electric guitar 1 made of a conductive metal or wound with a conductive metal thread are electrically connected to the control chip 10. In this manner,

p0038On the Tremolo system block 5, <figref idrefs="f0005">FIG. 5 (a)</figref> 5 (d). The sides run along these in the region of the rider inserts indicated at 16. The<figref idrefs="f0005">Fig. 5 (d)</figref> Shown in greater detail in FIG <figref idrefs="f0005">Fig. 5 (a)</figref> Shown in the <figref idrefs="f0005">Fig. 5 (a)</figref> Right. Since the tabs 15 and the rider inserts 16 are regularly made of metal and thus of a conductive material in an electric guitar 1, in order to avoid a short circuit between the strings electrically contacted via the leads 14, the rider inserts 16 over which the strings 6 a To 6f, be insulated from each other. For this purpose,<figref idrefs="f0005">Fig. 5 (a)</figref> (21).

p0039In the <figref idrefs="f0007">Figs. 7 (a) to 7 (d)</figref> Once again, details of the head 4 of the electric guitar 1 with the components of the device according to the invention arranged thereon can be seen <figref idrefs="f0007">Fig. 7 (d)</figref> A detail enlargement of the <figref idrefs="f0007">Fig. 7 (c)</figref> Indicated by D.

p0040In the <figref idrefs="f0008">Figs. 8 (a) to 8 (d)</figref> The mechanical units for adjusting the string tension consisting of the vortices 7, the vanes 8 and the servomotors 11 are once again detached from the head 4. It can be seen that all these units are seated on a common board 22, which contains further control elements for controlling the servomotors 11. The strings 7 are electrically connected to corresponding conductor tracks on the circuit board 22 via the metallic and thus conducting vortices 7.

p0041The device for automatically tuning the electric guitar 1 according to the present invention operates as follows:

p0042Pulling the push-pull potentiometer 13 activates the system. For this purpose,<figref idrefs="f0009">FIG</figref> , Which will be described below.

p0043The control chip 10 can now be given commands by striking one of the strings. The tones generated by striking the strings are converted by the pickups 12 into an electrical signal, which is converted into a frequency in the control. In the control, certain pre-programmed commands are stored, which are called up to a frequency within a certain tolerance. In this way, for example, the program for tuning one of the strings, for example the e-string 6f, can be called. When the program is activated, the control chip loads a reference frequency from a memory for this string, which serves as the set 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 the land under bus strings a signal to the board 22 and through the latter to the corresponding n servomotor 11 for moving Of the string voltage to reach the desired frequency. The control chip 10 monitors the change in the frequency and, when the desired frequency is reached, outputs a stop signal to the servomotor 11. In this way, all the strings can be tuned one after the other. A mathematical frequency filter is used as a routine for calculating the actual frequency from the electrical signal of the pickups, since this can calculate the frequency particularly quickly and reliably.

p0044Via an interface, which is not shown in the figures, different frequency presets for the strings can be given to the control chip 10, depending on which kind of tuning is to be selected (eg open tuning, etc.).

p0045Only two of the strings are required for the transmission of the control signals. The power supply for the circuit board 22 and the servomotors 11 are placed in the head 4 via two additional strings, here the strings 6f (low e-string) and 6e (a-string), so that a separate voltage source is not required there. The strings 6f and 6e are chosen to transmit the tension, since the deep e-string and the a-string are the thickest strings of the electric guitar 1 and thus rupture most rarely. Of the remaining four strings 6a to 6d, two arbitrary bus lines can be freely controlled by the control chip 10. In this way, the system is redundant and can also operate with one or even two torn strings of the strings 6a to 6d.

p0046Light-emitting diodes on the body 2, for example in the region of the pick-ups 12 below the strings 6a to 6f, can indicate the state of the control circuit 10 or the program sequence, thus simplifying the handling of the device. A "short instruction" can also be applied here, for example with the indication, by which of the strings 6a to 6f in which tone which commands are called. The frequencies assigned to the commands can be managed by the control chip 10 to match the current tuning of the electric guitar, that is, the user must always strike the same string with the same handle to retrieve a command, no matter how The guitar and thus the string is just tuned.

p0047In this exemplary embodiment, the system supplies power to the system externally via the amplifier cable with which the guitar is in any case electrically connected to an amplifier. In the<figref idrefs="f0009">FIG</figref> Is constantly monitoring the internal resistance of the electric guitar 1. This is high in the case of a normally played electric guitar 1. If the musician now pulls the push-pull potentiometer 13, the pickup 12 couples the pickup 12 from the jack socket for the amplifier cable and thus from the amplifier, and switches the control chip 10 on. As a result, the internal resistance of the electric guitar 1 decreases by at least a factor of 20. This recognizes the circuitry and turns off the amplifier cable from the amplifier, so that the electric guitar 1 can be "muted". Furthermore, the circuit switches a supply voltage, which can be obtained, for example, from the power supply of the amplifier, but also from an external power supply, to the amplifier cable. This voltage is then fed to the controller 10 and passed to the head 4 via the strings 6e and 6f. The device according to the invention can now operate. Upon completion of the voice, for example, setting up the circuit or applying new data, the musician switches the push-pull potentiometer 13 back to the normal position. The internal resistance of the electric guitar 1 rises again due to the pickup 12 which is now again connected to the amplifier cable. This is detected by the sound circuit according to FIG<figref idrefs="f0009">FIG</figref> And outputs the signals from the amplifier cable back to the amplifier, the musician can continue to play.

Reference list

p0048<dl id="dl0002"><dt>1</dt><dd>Electric guitar</dd><dt>2</dt><dd>body</dd><dt>3</dt><dd>web</dd><dt>4</dt><dd>head</dd><dt>5</dt><dd>Tremolo system block</dd><dt>6a-f</dt><dd>string</dd><dt>7</dt><dd>whirl</dd><dt>8th</dt><dd>wing</dd><dt>9</dt><dd>Pick Guard</dd><dt>10</dt><dd>Control chip</dd><dt>11</dt><dd>actuator motor</dd><dt>12</dt><dd>Pickup</dd><dt>13</dt><dd>Potentiometer</dd><dt>14</dt><dd>management</dd><dt>15</dt><dd>equestrian</dd><dt>16</dt><dd>Riding rider</dd><dt>17</dt><dd>drilling</dd><dt>18</dt><dd>thickening</dd><dt>19</dt><dd>sleeve</dd><dt>20</dt><dd>disc</dd><dt>21</dt><dd>area</dd><dt>22</dt><dd>circuit board</dd></dl>