DE10147710A1 - Method of operating a stringed instrument such as electric guitar, by detecting time at which conductive plectrum makes contact with string from electrical connection - Google Patents

Abstract

The method involves determining which of the strings (20) of the stringed instrument are contacted or stroked at what time point. The direction of the contact or stroke (forward or backward) is also determined. To detect the time point of contact, the time at which an at least partially conductive plectrum contacts the string is determined. Alternatively, strain gauges in the plectrum, or piezo-pressure sensors in the bridge or saddle, or in the plectrum may be used to determine the contact time point. Independent claims are also included for a stringed instrument, and for an arrangement with a stringed instrument and synthesizer.

Description

The present invention relates to an electronic Device for improving the sound of stringed instruments.

For an electric guitarist (electric guitarist) it is common the guitar sound through effect devices (such as chorus, reverb, Distortion or generally using functions in a synthesizer) to vary or beautify. Not always with the same To play effects, these effects must be quickly added and removed can be switched off. This requirement also applies to Sound improvements on other stringed instruments.

Electronic effects devices such as digital ones are usually used Switch on or on the guitar synthesizer using the footswitch or footswitch switched off or the desired sound variations selected. You can e.g. B. embellish a guitar solo with effects, by pressing a foot switch before and after the solo.

The switching on and off of effect devices such. B. a Footswitch synthesizer works relatively slowly (not less than 50 ms). It is impossible to use tones with a foot switch different effects targeted, e.g. B. quickly successively to sound.

The object of the invention is therefore a method and Specify device that allow tones with different effects targeted, e.g. B. in quick succession, to sound.

This object is achieved by the inventions according to the independent claims solved. Advantageous further developments of Invention are characterized in the subclaims.

Usually the strings of a string instrument are made using a pick or other aids such as coins or with Hand or finger struck or painted with a bow.

The task is solved by the Time of attack and the direction of attack (up or down) of the string or the plectrum or other aids or the hand or the finger or the bow as a "stop / Direction information "recognized electronically and both signals together to control effect devices be used. This stop / direction information is then available available for any tax task. For example chipped tones can be given a distortion effect and open notes are assigned the chorus effect. So the guitarist chooses z. B. of Plektrons the effect of the sound to be played and can therefore even quickly played consecutive tones or chords with different, individual effects if the stroke itself and its direction for each tone separately detected and processed electronically.

The information in the direction of movement of the string after a serve or discount as dynamic Movement states are included, can be targeted to Sound improvement can be used. This will like mechanical switches Make foot switches etc. redundant in the future. Modern guitar Synthesizers currently do not offer the option of one To apply a different sound effect to the tee than one Surcharge.

The basic principle of those described below Detection of the stop / direction information is based on the Combination of a simple electrical switch and, in one first advantageous embodiment, one on the Measuring device based on Faraday's law of induction. The Switch serves to close the time of the striking itself detect. The switch should be closed when that Plectron touches the string. The plectrum and the String be electrically conductive. The measurement of a Induction voltage in the struck string serves the direction the movement caused by the plectrum (deflection from the rest position) of the string. With this device the direction information becomes automatic and very fast detected without it being a mechanical switch and its Activity by the musician is required, as it currently is State of the art.

In a second, advantageous embodiment, the Direction detection by measuring the induced in the magnetic field Voltage in the coil of a conventional pickup, which is laterally offset under the string, performed.

In a third, advantageous embodiment, the Direction detection using a special design electromagnetic pickup with two wound in series in the opposite direction switched spools guaranteed under each string, being this special design like a standard pickup handle is. This has the advantage that musicians with the Use of standard electromagnetic pickups are already familiar. The time of the attack can be with Using the signal from a conventional pickup or be determined by means of the electrically conductive plectron.

In a fourth, advantageous embodiment, the Direction of movement of the string by ultrasonic measurement or Microwave radar on the hand of the musician or on the plectrum or another device. This has the Advantage that lightweight, especially miniaturized components can be used.

In further advantageous embodiments, the Direction of movement of the string by evaluating Video recordings or by means of light barriers or by means of Strain gauges in the plectrum or by means of piezo pressure sensors in the Bridge or saddle of the string instrument or in the plectrum detected.

In many embodiments, the string can be electrically conductive or be non-conductive, which extends the scope of the Invention of electric to acoustic stringed instruments extended.

The problem of stroke detection, i. H. the time of the Stroke alone is state of the art already solved; without a stop detection, a digital would Guitar synthesizers don't know at what time played sound converted into a digital control signal shall be. Except in more detail below described new possibilities of stroke detection can always can also fall back on the known possibilities.

With the known possibilities of stroke detection, the Moving the string in with a standard pickup converted an electrical voltage signal. In one of these known design convert pickups the mechanical Vibrations of strings struck using so-called Stratocaster into electrical AC voltages. Stratocaster consist of electrically conductive coils used in older Models around bar magnets, with newer ones wrapped around soft iron pins with bar-shaped ferrite magnets on the underside. The field lines of the magnets flow through the strings on one Part of their length. The strings are in the rest position magnetic flux constant. The string moves after a stop from the rest position, deforms because of the electrical Conductivity of the string the spatial course of the field lines. This changes the magnetic flux through the coil. Of a string vibrating at a certain frequency therefore an AC voltage of the same frequency in the coil induced. The amplitude of the voltage of the known pickups depends on the strength of the attack (the amount of Deflection from the rest position of the string), its electrical Conductivity and the distance between the string and the magnetic pole. Known Create pickups that work with this principle Voltages with amplitudes in the range of a few hundred millivolts. The signals are amplified separately and rectified and serve as input signals for one non-inverting Schmitt trigger. Exceed the rectified signals provides a predetermined amplitude the trigger output for each input signal associated (high level) output signal, at which the time of each Attack is recognized individually. With hexaphonic Pickups can use this stop detection for each string separately be made.

In another version of known pickups rather use them instead of coils and magnets Piezo elements built into the bridge of the guitar. The jetty is a vertical little board on the Top of the string instrument on which the strings rest.

There is a separate piezo element for each string in the respective Bridge segment used. Each piezo element is separate wired. The connection cables can either be interconnected be, or they are continued separately to the signal to feed every single string to a guitar synthesizer. Piezo elements can also be placed in the bridge or saddle the guitar. The saddle is the one at the top String instruments attached to the end of the fingerboard Cross bar on which the strings rest. With such piezo Pickups can be electrically conductive or non-conductive Strings are used.

In the present invention is compared to the known ways of detecting the time of the attack, however a particularly simple concept for stroke detection described. Since the plectron itself is electrically conductive and is electrically connected to a voltage source, as soon as the plectron flows the electrically conductive string contacted, through the plectrum and string to the ground Current pulse, which clearly defines the time of the attack.

For the subsequent measurement of the direction of movement of the string by means of the new, advantageous first embodiment Using the induction principle, the string is located like in known designs of conventional pickups, in one Magnetic field. As the string comes out of its rest position by the stop is deflected, it represents one moved in the magnetic field Conductor in which an induction current is generated. about the internal resistance of the string arises accordingly electrical voltage, the polarity of this electrical voltage depends on the direction of movement of the string. With the help of a simple evaluation electronics that recognize this polarity, you can therefore change the direction of movement of the string against the Rest position and thus the direction of the pick determine. If you measure the direction of movement immediately after Timing of the string stops up to the maximum deflection the string, you get the desired, complete Lifting / direction information. Every string stop is accurate assigned a direction of movement.

Compared to the well-known pickups, which only the Attack time, which will recognize frequency and amplitude here also the stop direction by recognizing the polarity of the induction voltage identified.

The published patent application DE 199 17 757 A1 does a scan of string vibrations electrical Musical instruments described in which electrically conductive strings vibrate in a magnetic field and the induced in them Voltage of any signal formers, signal amplifiers or Transducers is fed. However, the signals are not there used to provide information about the direction of a particular Plectronic attack to win so that the musician by means of arbitrarily made by him at precisely this attack Determination of the direction of the artistic design the sound of this attack can act. The signals should only be processed there technically without that to the creative means of sound enhancement by giving direction to each individual, individual stop is targeted by the musician.

It is also known from DE 195 28 051 that the 6 analog outputs of a guitar can be supplied with 6 separate distorters and the distortion can be controlled separately. This means that the tones or tone sequences generated on individual strings are each equally, ie with the same electronic tool, e.g. B. can be edited by means of distortion. However, this publication also lacks the teaching of how each tone of a tone sequence could be accessed individually by means of a stop / direction detection in order to deform precisely this single tone in terms of design, or, as in the case of successive notes of a string, each individual tone compared to a preceding or following tone Sound different, e.g. B. could be deformed by distortion or chorus.

It is also known from DE 199 13 249 A1 that through a sensor built into a plectrum, e.g. B. one Thin film sensor, the parameters of an effects device via finger pressure can be controlled. Again the teaching is limited by all notes produced on one string with the same electronic tool, namely the effects device, e.g. B. one Distortion, can be deformed. An individual deformation single, consecutive tones by different Effects devices are not possible.

In several executable examples, the details of the stop / direction detection and an associated digital circuit for control tasks are to be explained in more detail with reference to the schematic FIGS. 1 to 10. In the figures, recurring components are provided with the same reference numerals.

In detail shows:

Fig. 1, the electrically conductive plectrum contacted with the electrically insulated power cable,

Fig. 2 shows the circuit diagram of the stop timing of detection, for example the depth and the high E string (first subscript e),

Fig. 3, the digital processing (normalization and time delay) on the results of the arrangement according to Fig. 2 stop timing signals,

Fig. 4 schematically shows the arrangement of the magnets on the body of the guitar (contour line) for the stop direction detection,

Fig. 5 is a block diagram of the stop direction detection,

FIG. 6a shows a conventional electromagnetic pickup,

Fig. 6b shows the laterally offset installation of a conventional electromagnetic pickup, and

Fig. 6c, the special design of an electromagnetic pickup,

Fig. 7, the apparatus for detecting the direction Plektronbewegung using ultrasonic or microwave Doppler effect measurement,

Fig. 8, the cohesive, a digital circuit Anschlagzeitpunkts- and direction detection for a string,

FIG. 9 shows the extension of the digital circuit from FIG. 8 to the detection of the timing and direction of two strings and

Fig. 10, the extension of the digital circuit shown in FIGS. 8 and 9 for Lifting / direction detection for a stringed instrument with four strings.

Detection of the time of the attack

In the following, reference is made to FIG. 1. In one embodiment, the musician holds an electrically conductive plectron 10 in his hand, to which a power cable 11 is electrically contacted. The cable leads to a voltage source (not shown) that has a maximum voltage of e.g. B. Ub = 5 V. The voltage supply can be implemented, for example, by a battery built into the guitar, the negative pole of the battery being connected to the ground connection of the guitar. The electrically conductive plectron 10 is connected via the power cable 11 to the positive pole of this battery (not shown). The guitar strings (not shown) must be electrically conductive for this embodiment of the stop detection.

In the preferred, simplest embodiment, the plekaron 10 is constructed homogeneously and consists of metal. The cable 11 is soldered to position 12 thereon, as can be seen in FIG. 1. The string (not shown) is struck with the tip 13 of the pick 10 .

If the electrically conductive plectron touches the tip 13 of the electrically conductive string at the stop, this represents the closing of an electrical contact (switch). A build-up of the internal resistance of the string during mechanical contact between the plectron 10 and the string (not shown) Voltage U (t). In this way, the digital information "Stop Yes / No?" to disposal.

The goal is to find a stop for each string available separately. For the e, a, d, g, b strings and the high The guitar's e-string should have a separate one Voltage pulse U (t) can be obtained. As with an electric guitar normally the bridge is grounded and conductive with all 6 strings is connected, you do not easily get any separately evaluable Voltage signals per string. So the strings have to come off the bridge be electrically isolated. The web is made of one electrical non-conductor manufactured.

So that a tensioned string does not slip through the bridge, the string is wound through a hole in the bridge threaded, with a so-called ball end at the end of the string located. This ball end is bigger than the hole; to this This prevents the string end from slipping. This ball end is electrically connected to the string. In a first embodiment, the string can be attached to the ball end a resistance z. B. brazed and the other side of this Resistance via a power cable to the ground connection of the E- Guitar. Alternatively you can use the resistor solder to the saddle, on the one hand the saddle is isolated from the bridge, on the other hand at the point of contact of the string there is a conductive connection on the saddle. This apply to all 6 strings of the guitar.

In the following, reference is made to FIG. 2. With the switch open, ie as long as the plectrum z. B. does not touch the deep e-string, the following applies to the "signal output" of this string: UE (t) = 0, ie UE delivers the time-constant low level for the subsequent signal processing. If the circuit is now closed by striking the string by means of the plectron, in this exemplary embodiment UE (t) = Ub = 5 V is considered to be a brief high-level signal for the duration of the stroke (a few milliseconds). The same applies to each of the other strings with the signal output associated with the respective string.

As an example, FIG. 2 shows the resistors 22 and 23 of the low e-string 20 and high e-string 21 as well as the signal outputs Ue, t (t) and Ue, h (t) of the low (second index t) and high (second Index h) e-strings 20 and 21 . For reasons of clarity, the resistances and signal outputs of the a, d, g, and h strings are not shown in FIG. 2 and are in the area of the dotted lines. Further, it is in Fig. 2, only one and the same conductive plectrum 10 can be struck with which each of the 6 strings. The broken circles 24 in this figure schematically represent the contact between the electrically conductive plectron 10 and the electrically conductive string 20 or 21 .

In order to make the circuit in FIG. 2 absolutely functionally reliable, a non-inverting Schmitt trigger (not shown) can be connected to each signal output, which ensures the clear distinction between high or low level signals.

In order that the short-term signals Ue, t (t) or Ue, h (t) from FIG. 2 can be used technically for the detection of stops, they have to be standardized and delayed, as shown in FIG. 3.

• 1. Ein Monoflop 30 erzeugt aus jedem Anschlagssignal, hier als Beispiel Ue, t(t), einen Impuls mit definierter Impulsdauer. Dazu wird der Impuls Ue, t(t) zunächst durch einen Normierer 32 normiert. Anschließend wird der normierte Puls durch die Hintereinanderschaltung von zwei Invertierern 32, 33 verzögert. Da der mechanische Schalter, bestehend aus dem leitenden Plektron und der leitenden Saite, beim Saitenanschlag prellt, wird ein nicht-nachtriggerbares Monoflop 30 eingesetzt. Daher erhält man bei jedem Anschlag am Ausgang des Monoflops genau einen Impuls mit definierter Impulsdauer. Die Impulsdauer wird so gewählt, dass sie deutlich länger ist als die sehr kurzzeitige Kontaktdauer zwischen Plektron und Saite. Jedoch muss die Impulsdauer viel kürzer sein als das Zeitintervall zwischen zwei Saitenanschlägen des Musikers auf der gleichen Saite.
• 2. Der Impuls am Ausgang des Monoflops 30 wird zeitverzögert an den endgültigen Ausgang der Anschlagerkennung weitergeleitet. Die Bewegungsrichtung der Saite muss mit dem vorangehenden Saitenanschlag und nur mit diesem korreliert werden, damit beide Signale in Koinzidenz auch bei schneller Tonfolge weiterverarbeitet werden können. Hierfür wird die Zeitverzögerung durch eine gerade Anzahl hintereinander-geschalteter Inverter 32 und 33 realisiert, wobei jeder Inverter 32 und 33 durch seine Signallaufzeit zur Zeitverzögerung beiträgt.

This further processing takes place in two steps:

• 1. A monoflop 30 generates a pulse with a defined pulse duration from each stop signal, here as an example Ue, t (t). For this purpose, the pulse Ue, t (t) is first normalized by a normalizer 32 . The normalized pulse is then delayed by the series connection of two inverters 32 , 33 . Since the mechanical switch, consisting of the conductive plectrum and the conductive string, bounces at the string stop, a non-retriggerable monoflop 30 is used. Therefore, each time you stop at the output of the monoflop you get exactly one pulse with a defined pulse duration. The pulse duration is chosen so that it is significantly longer than the very short contact duration between the plectrum and the string. However, the pulse duration must be much shorter than the time interval between two strings by the musician on the same string.
• 2. The pulse at the output of the monoflop 30 is passed on to the final output of the stop detection with a time delay. The direction of movement of the string must be correlated with the preceding string stop and only with this so that both signals can be processed in coincidence even with a fast tone sequence. For this purpose, the time delay is realized by an even number of inverters 32 and 33 connected in series, each inverter 32 and 33 contributing to the time delay by its signal propagation time.

This processing of the signals for the final touch detection according to FIG. 3 has to be done electronically separately for all 6 strings.

Detection of the direction of movement of the string

Swings according to the advantageous first mentioned above Embodiment of the direction detection an electrically conductive String in the magnetic field, so after Faraday's Induction law in the string an electrical AC voltage UP0 (t) induced. Here the polarity of the electrical depends AC voltage from the current direction of movement of the string.

An advantageous arrangement of the magnet on the guitar is shown in FIG. 4. The figure schematically contains the contour of the guitar body 1 and the magnet 40 .

Advantageously, the string 20 , in the example the deep e-string, is struck by means of the plectrum (not shown) at the height of the magnet 40 at point 46 , because here both the magnetic field and the deflection of the string 20 have the maximum amount. The voltage pulse UP0 (t) is caused in the electrically conductive string 20 which is moved in the magnetic field by electromagnetic induction. The magnet 40 is shown schematically with its N poles 41 and 42 .

To measure the induction voltage, the terminals of a suitable measuring sensor (not shown) can be electrically contacted with the string 20 on the bridge (not shown) and at the upper end of the string 20 . The string moves in FIG. 4 in the direction of tee 43 so UP0 (t) is negative.

In order to obtain digital information as to whether the string is moving in the striking direction 43 , the signal UP0 (t) from FIG. 4 is used as an input signal for an inverting comparator 50 shown schematically in FIG . The comparator 50 recognizes the sign of the electrical signal UP0 (t) from FIG. 4 and supplies a HIGH level signal for a string movement in the direction 43 . The value 0 V is applied as the reference voltage to the non-inverting input of the comparator 50 .

If the input signal is negative, the comparator 50 supplies a high level signal; if it is positive, the comparator 50 supplies a LOW level signal (not shown). Therefore, a high level signal at the output of the comparator 50 indicates that the string (not shown in FIG. 5) is moving in the direction of the strike.

This information regarding direction detection (direction of impact or strike) cannot be obtained from the electrical signal of a conventional electromagnetic pickup ( FIG. 6a) if it is - as usual - positioned directly under a string.

The conventional pickup 60 consists of a coil 61 and a magnet 62 . Every movement of the electrically conductive string 20 in the field of the magnet 62 from its rest position 64 causes a field change which changes the magnetic flux through the coil 61 and induces a voltage in the coil 61 . The amount of the change in the flux and thus the amplitude of the voltage induced in the coil 61 is dependent on the distance 63 between the string 20 and the coil 61 .

After striking, the string 20 vibrates in all three spatial directions (not shown), initially with high amplitudes in the respective striking direction of the plectrum. Depending on the strength of the stop and the damping, the string vibrates with different amplitudes in the three spatial directions. Significant for the amplitude of the voltage induced in the coil 61 , however, are only transverse string vibrations, i.e. string movements perpendicular and parallel to the surface of the guitar body (not shown) or parallel or perpendicular to the coil axis 66 .

Among these two transverse directions of movement, the influence of the deflection parallel to the coil axis 66 , i.e. perpendicular to the guitar body, on the level of the amplitude of the induced voltage dominates, because a deflection in this direction with a change 65 in the distance 63 between the string 20 and the coil 61 or the magnet 62 , measured parallel to the coil axis 66 .

In contrast, the distance 63 between the string 20 and the coil 61 or magnet 62 changes only slightly in the case of a transverse deflection purely perpendicular to the coil axis 66 . But this is exactly the direction actually struck parallel to the guitar body. The field change caused by this deflection or the voltage induced in the string 20 is accordingly much smaller than that which is generated by a string movement parallel to the coil axis 66 .

The conventional pickup can thus neither determine the direction nor the orientation of a string movement parallel to the surface of the guitar body 1 . A conventional electromagnetic pickup 60 , which is attached directly under the string 20 , thus does not generate its electrical signal from the movement of the string 20 in the opening and tapping direction, but only from the proportion of the string vibration perpendicular to the fingerboard (not shown in FIG. 6a ) or perpendicular to the body of the stringed instrument 1 (see also H. Lemme, Elektro-Gitarren-Sound, Richard Pflaum-Verlag, Munich, 1994, page 57).

A feasible, advantageous embodiment of the direction detection by means of a conventional pickup 60 now consists in placing the pickup 60 laterally, not directly under but instead according to FIG. 6b, and with the orientation under string 20 changed by 90 degrees compared to the normal installation direction, that either the magnet and coil axis are oriented parallel to the surface of the instrument and perpendicular to the strings, or that the magnet is oriented perpendicular to the surface of the instrument and the strings and the coil is oriented parallel to the surface and perpendicular to the strings. This advantageously reverses the effects of the directions of the string vibrations with respect to the voltages induced in the coil compared to the conventional arrangement ( FIG. 6a).

Among the tensions that are induced in the coil 61 by the two transverse directions of movement, the one that is caused by the deflection of the string 20 parallel to the surface of the guitar 1 , ie parallel to the changed coil axis 66 , now dominates. In contrast, the distance between coil 61 and string 20 changes only slightly during the other transverse string movement perpendicular to the coil axis 66 and perpendicular to the surface of the guitar body 1 . The field change caused by this deflection or the voltage induced in the coil is accordingly much smaller than that which is generated by a string deflection parallel to the surface of the guitar 1 and coil axis 66 , ie in the direction of impact or strike 43 or 44 .

The conventional pickup 60 in the arrangement according to FIG. 6b, when laterally offset under the string 20, can determine both the direction and the orientation of a string movement parallel to the surface of the guitar body 1 .

In the third preferred embodiment, the direction of movement of the string is determined by a special design of an electromagnetic pickup, as shown in FIG. 6c. The strings must also be electrically conductive here. In this embodiment, the string is preferably struck with a conventional plectrum.

This pickup can be mounted under the string 20 like a conventional pickup 60 . While a conventional electromagnetic pickup 60 only reliably converts the transverse string movement in direction 45 perpendicular to the surface of the guitar (not shown here), i.e. parallel to the coil axis 66, into an electrical signal, the special design described here also delivers an electrical signal parallel to the transverse directions of movement P. to the guitar surface or perpendicular to the coil axis 66 .

The special design is shown in FIG. 6c of two left and right of the string 20 arranged coils 68 and 69 having their axes perpendicular to the string and to the surface of the guitar body 1 and are parallel to each other. A common magnet 62 is also provided, the axis from the north to the south pole of the magnet being perpendicular to the surface of the stringed instrument. The coils are electrically connected in series, with the coil 68 wound in the opposite direction to the coil 69 (or the polarity of the connections of coil 68 is reversed with respect to the coil 69 ).

If the string 20 moves in the direction of impact 43 , the field of the magnet 62 is distorted in such a way that the field lines, which concentrate more strongly on the electrically conductive string 20 , collect more strongly on the impact side. The field strength increases on the impact side and decreases on the impact side. In the coil 68 , z. B. induces a positive voltage. In coil 69 there is a weakening of the field strength. If coil 69 were wound like coil 68 , this would result in a negative induced voltage. However, since coil 69 is wound in the opposite direction, a positive induced voltage results, just as in coil 68 . If the string 20 moves in the striking direction 44 , a negative voltage is induced in coil 68 and in coil 69 in this example.

Coil 68 and coil 69 are connected in series, ie the voltage add up. The sign of the electrical signal of this series connection then contains the information as to whether the string is moving in the up or down direction.

The strung string 20 vibrates not only in the directions of movement of the impact 43 or the stroke 44 , but also in the direction of movement 45 perpendicular to the surface of the guitar 1 . This direction of movement induced in both coils 68 and 69 a signal that will be treated as "noise" to the signals with respect to the directions 43 and 44 of the two coils 68 and 69 must be. The magnitude of the interference signal in both coils 68 and 69 is exactly the same, but of the opposite sign. Since the coils 68 and 69 are connected in series, the two contributions of this disturbance in the sum voltage of the series connection of these coils cancel themselves out.

If the special design from FIG. 6 c is extended to a guitar with 6 strings (not shown), then two coils 68 and 69 are required per string. The coil diameter should be only half as large as the side spacing of two adjacent strings 20 . It is sufficient to place a common magnet 62 under all 6 strings.

The described design of the special design of an electromagnetic pickup according to FIG. 6c, which converts the string movement into an electrical signal parallel to the surface of the guitar, is only one example among many other possibilities of combinations of a coil (or several coils) and a magnet ( or several magnets) and various forms of arrangement of the coils and magnets under or laterally offset under the strings and the evaluation electronics for detecting the direction of the movement of the string.

According to a fourth embodiment of the device for recognizing the direction of the plectron, the use of an ultrasound component, which is directed at the hand of the musician or at the plectron itself, is provided, as shown in FIG. 7.

First, the ultrasonic component 70 sensor consisting of transmitter 71 and receiver 72 z. B. mounted on a line that is at right angles on all 6 strings 20 and runs approximately through the point of contact 46 of the plectrum 10 with the string 20 at the moment of the attack. For simplicity, only one string 20 is shown in FIG. 7, the other guitar strings run parallel to this string.

The ultrasound waves emitted by the ultrasound transmitter 71 are reflected by the hand (not shown) or by the plectron 10 and then received again by the receiver 72 of the component 70 .

The direction of movement of the hand, which is at the same time the direction of the plectrum 10 and the string 20 at the time the string is struck, is recognized by measuring the Doppler effect:
If the hand or the plectron 10 moves in the tapping direction 44 (in FIG. 7 the direction towards the component 70 ), the received ultrasound wave reflected by the hand or the plectron 10 has a higher frequency than that from the ultrasound transmitter (Transmitter) 71 broadcast wave. If the hand or plectron 10 move in the direction of impact 43 , the effect is reversed and the received, reflected wave has a lower frequency than the transmitted wave.

If the transmitted and the received ultrasonic waves are converted into equal voltages which are proportional to the received frequency and these two direct voltages are applied to the inputs of a comparator or Schmitt trigger (not shown in FIG. 7), the result is obtained at the output of the comparator or Schmitt -Triggers digital information on whether the hand and the plectron move in the direction of impact or strike for this stop.

A variant of this device, the stop direction too determine is a measurement instead of ultrasonic waves using microwave radar, which is also the Doppler effect served. To do this, the ultrasound Measuring device (transmitter and receiver) by appropriate Microwave transmitters and receivers can be replaced.

Literature shows that one can measure very precisely using the Doppler effect and also with very small distances (in the millimeter range). B. measuring the flow direction of the blood and its flow rate describe (ELV Journal "magazine for applied electronics" Issue 1/2001, p 16). Sensors with separate transmit and receive membrane allow to take measurements at close range from about 20 mm (ELV Journal 1/2001, page 17).

You could also add an additional stop direction Integrate detection into the system by using the plectrum formed from two electrically conductive layers that are separated from each other by an isolator. If the layers have different electrical resistances, this leads to different voltage drops across the conductor chain Cable / plectrum / string. These can also be used for Control of effects can be used.

In a further executable training, the hand or plectron movements through the use of reflection Detected light barriers, which are under the string and by hand or by plectrum or by string reflected light and thus the current string position and hereby measure hand or plectron movements. Can too Photoelectric sensors can be installed parallel to the strings: for example, the transmitter on the saddle and the receiver on the bridge of the guitar attached to the current position of the Recognizing plectrons and their movement.

Finally, in another embodiment Strain gauges to be glued to a flexible plectron Detection of the point of time and direction. there leads a surcharge z. B. to stretch and one Resistance increase during a discount e.g. B. for upsetting and thus to reduce the resistance of the Strain gauge leads. Therefore, one can use the change in resistance distinguish a premium from a premium. Can continue with strain gauges on the plectrum also the time of the attack itself. In this case, the Strings and the plectrum also made of electrically non-conductive Material are made.

All of the above-mentioned embodiments at the time of the attack and direction detection allow not just the time of striking a string and its direction of movement determine, but also the number and Individuality of all strings struck simultaneously or one after the other and their times of attack and forms of movement be to z. B. a chord with a different effect provided as individually played tones or tone sequences.

Associated digital circuit for control tasks

The digital circuit for control tasks combines the detection of the time of the attack, which, for. B. is made by means of an electrically conductive plectrum, with the direction detection z. B. according to the electrodynamic (induction) principle of Fig. 1 to 5, the laterally offset arrangement of the conventional pickup under the string ( Fig. 6b) or the special design of an electromagnetic pickup from Fig. 6c or one of the other described above, advantageous Embodiments for direction detection.

To illustrate, FIG. 8, the contiguous digital circuit 80. Herein, for example, Ue, t (t) is the digital (touch) signal of the deep e-string, which is processed by means of the touch point detection 30 from FIGS. 2 and 3. UP0 (t) is the electrical (moving direction) signal from the stop direction detection 50 of FIG. 5, which recognized tapped during the induction principle, at both ends of the low E string of the guitar of Fig. 4 and Fig. 5 and becomes. UG (t) is the electric guitar signal of a conventional electromagnetic pickup.

If the deep e-string is struck with a surcharge, z. B. the distortion effect 84 can be activated. The chorus effect 83 is activated in the event of a discount.

After each stop time and direction detection in the switching elements 30 and 50 , the direction signal is transferred to the flip-flop 81 with the output of a signal to the output Q. Finally, the switch 82 controls the selection of the effect devices 83 and 84 , their signals downstream amplifiers (not shown) are supplied.

While the digital circuit in FIG. 8 only works with the detection of the timing and direction of a single string, FIG. 9 shows the corresponding executable circuit for two strings. It consists of monoflops 30 and 31 for normalization and time delay according to FIG. 3 and from comparators 50 and 51 according to FIG. 5 and from logic switches 91 and 92 , a multiplexer 93 and a flip-flop 81 according to FIG. 8. For example UP0 (t) is the electrical direction signal of the deep e-string and UP1 ( t) the electrical direction signal of the a string of the electric guitar. Switches 91 (logical AND) and 92 (logical OR) allow sound processing to be carried out on strings struck simultaneously or in succession. The multiplexer 93 controls the flip-flop 81 , which, as in FIG. 8, responds to an effects device (not shown) which causes the acoustic implementation of the selected guitar sound effect. The table entered in FIG. 9 illustrates the function of the multiplexer 93 . It indicates which input (d0 or d1) of the multiplexer 93 is switched through by the multiplexer 93 as a function of the level on the control line S.

If the e-string (not shown in FIG. 9) is struck alone, the output 30 is HIGH and the output 31 is LOW. The AND gate 91 then supplies LOW on the line S. Thus, the multiplexer, as indicated in the table, switches the direction information d0 of the e-string to the line Z. Since the OR gate 92 also enables the flip-flop, it switches the line Z to the output Q and thus d0 to Q. The sound effect is then determined by the directional information d0 of the e-string.

If the a strings (not shown in FIG. 9) are struck alone, the output 31 is HIGH and the output 30 is LOW. At the input of the AND gate 91 , this LOW is inverted to a HIGH. The AND gate 91 then supplies HIGH on line 5 . The multiplexer thus switches the direction information d1 of the a string to line Z, as indicated in the table. Since OR gate 92 additionally enables the flip-flop, it switches line Z to output Q and thus d1 to Q. The sound effect is then determined by the direction information of the a string.

If both strings (not shown in FIG. 9) are struck simultaneously, the outputs 30 and 31 are HIGH. The AND gate 91 then supplies LOW on the line S. Thus, the multiplexer, as indicated in the table, switches the direction information d0 of the e-string to the line Z. Since the OR gate 92 also enables the flip-flop, it switches the line Z to the output Q and thus d0 to Q. The sound effect is then determined by the direction information of the e-string. So the e-string has priority.

For expanding to more than two strings, this can be done The basic principle of this circuit can be retained. Only the O- DER function and the multiplexer must have additional inputs have, and the control logic at the control inputs of the Multiplexers are becoming more extensive.

Fig. 10 shows the circuit for determining a control signal for controlling a Q-effect device for four strings (e, a, d, g). The mode of operation and the designation of the objects is quite analogous to FIG. 9.

It is of course always possible to use a separate, independent circuit according to FIG. 8 for each string. One possibility is to combine pairs of strings with the circuit according to FIG. 9.

In addition to the stop detection using a conductive plectrum can the circuit described with minor changes also in combination with other known methods for Stop detection can be used.

Various combinations of are within the scope of the invention Attack time and the direction detection the various described embodiments possible.

Claims (31)

1. A method of operating a string instrument ( 1 ), characterized in that it is determined
which of the strings ( 20 ) of the stringed instrument is struck or deleted at which time (striking time) and
whether the stroke or strike is a markup or markdown (direction of stroke). 2. The method according to claim 1, characterized in that to determine the time of striking it is determined when an electrical contact between the strings ( 20 ) and an at least partially electrically conductive plectrum ( 10 ) is closed. 3. The method according to claim 1, characterized in that the stop time is determined by means of strain gauges in the plectrum ( 10 ). 4. The method according to claim 1, characterized in that the time of attack is determined by means of piezo pressure sensors in the bridge or the saddle of the string instrument ( 1 ) or in the plectrum ( 10 ). 5. The method according to claim 1, characterized in
that a plectron is used to strike the strings, the two sides of which are electrically insulated from one another, each side of the plectron being able to close a switch when the strings of the stringed instrument are touched, as a result of which the time of striking can be recognized; and
to determine which of the two switches was closed to determine the direction of the stop. 6. The method according to claim 1, characterized in that the polarity of the voltage induced in the deflected strings ( 20 ) in a magnetic field is determined to determine the stop direction. 7. The method according to claim 1, characterized in
that a pickup ( 60 ) with at least one coil ( 61 ) and at least one magnet ( 62 ) is used to determine the direction of attack of a string,
that the at least one coil ( 61 ) and the at least one magnet ( 62 ) of the pickup are laterally offset under the string ( 20 ), and
that the at least one coil ( 61 ) and the at least one magnet ( 62 ) are arranged and oriented in such a way that they convert the movement of a string ( 20 ) of the string instrument ( 1 ) parallel to the surface of the string instrument ( 1 ) into an electrical signal. 8. The method according to claim 1, characterized in
that a pickup ( 60 ) with two coils ( 68 , 69 ) wound in opposite directions is used to determine the stop direction, or
that a pickup ( 60 ) with two coils ( 68 , 69 ) wound in the same direction is used, in which the polarity of the connections is interchanged,
that the coils ( 68 , 69 ) are connected in series, and
that the polarity of the voltage induced in the coils ( 68 , 69 ) is determined. 9. The method according to claim 1, characterized in that the stop direction is measured by an ultrasonic Doppler effect measurement on a plectrum striking the strings ( 10 ) or on a hand striking the strings. 10. The method according to claim 1, characterized in that the stop direction is measured by means of the plectron ( 10 ) or the hand reflected microwave intensity with the Doppler effect. 11. The method according to claim 1, characterized in that the stop direction is measured by recording the movement of the plectrum ( 10 ) or the hand by means of at least one video camera. 12. The method according to claim 1, characterized in that the stop direction is measured by recording the movement of the hand or the plectrum ( 10 ) or the strings ( 20 ) by means of light barriers. 13. The method according to claim 1, characterized in that the stop direction is measured by means of strain gauges in the plectrum ( 10 ). 14. The method according to claim 1, characterized in that the stop direction is determined by means of piezo pressure sensors in the bridge or the saddle of the stringed instrument ( 1 ) or in the plectrum ( 10 ). 15. The method according to any one of the preceding claims, characterized in that the fixed stop direction is used to control a synthesizer. 16. Device for measuring the timing of a string touch,
with an electrically conductive string ( 20 ) of a string instrument ( 1 ),
with an electrically conductive plectron ( 10 ) for striking the electrically conductive string ( 20 ), and
with means for establishing an electrical contact between the electrically conductive string ( 20 ) and the electrically conductive plectrum ( 10 ). 17. The apparatus according to claim 16, characterized in that the plectrum ( 10 ) has two electrically conductive layers separated from one another by electrical insulation. 18. Plectrum ( 10 ), in which at least one strain gauge is integrated. 19. Plectrum ( 10 ), in which at least one piezo pressure element is integrated. 20. Device for operating a string instrument ( 1 )
with a pickup ( 60 ) with at least one coil ( 61 ) and at least one magnet ( 62 ),
wherein the at least one coil ( 61 ) and the at least one magnet ( 62 ) are arranged such that they convert the movement of a string ( 20 ) of the string instrument ( 1 ) parallel to the surface of the string instrument ( 1 ) into an electrical signal. 21. The apparatus according to claim 20, characterized in
that the pickup ( 60 ) is laterally offset under the string ( 20 ) on the body of the stringed instrument ( 1 ) and
that the direction of the axes ( 66 ) of the at least one coil ( 61 ) and the at least one magnet ( 62 ) are oriented such that either the coil axis ( 66 ) and the axis from the north to the south pole of the magnet ( 62 ) are parallel to the surface of the string instrument ( 1 ) and perpendicular to the string ( 20 ), or that the axis from the north to the south pole of the magnet ( 62 ) perpendicular to the surface of the string instrument ( 1 ) and to the direction of the string ( 20 ) and the coil axis ( 61 ) are oriented parallel to the surface of the string instrument ( 1 ) and perpendicular to the string ( 20 ). 22. The apparatus according to claim 20, characterized in
that the pickup ( 60 ) can be positioned under the string ( 20 ) on the body of the string instrument ( 1 ),
that a magnet ( 62 ) is provided, the axis from the north to the south pole of the magnet being oriented perpendicular to the surface of the stringed instrument,
that two coils ( 68 , 69 ) arranged on the left and right of the string ( 20 ) are provided, the axes of which are oriented perpendicular to the string ( 20 ) and to the surface of the string instrument ( 1 ) and parallel to one another,
that the coils are electrically connected in series,
that the coil ( 68 ) is wound in the opposite direction to the coil ( 69 ) or the polarity of the connections of the two coils ( 68 , 69 ) is interchanged. 23.string instrument ( 1 )
with at least two light barriers which detect the movement of the plectron ( 10 ) or the strings ( 20 ),
the transmitters and receivers of the light barriers either being mounted on the body of the stringed instrument ( 1 ) under the strings ( 20 ) outside the area ( 46 ) in which the string stop occurs, or
the light barriers are mounted parallel to the strings and the transmitters are attached to the saddle and the receivers are attached to the bridge of the string instrument. 24.string instrument ( 1 )
with at least two light barriers, which detect the movement of a hand of a player of the string instrument,
the transmitters and receivers of the light barriers being mounted on the body of the stringed instrument ( 1 ) in the area of the string stop. 25. String instrument ( 1 ) with a string ( 20 ), characterized by means for measuring (a) the time of striking and (b) the striking direction of the string ( 20 ). 26. String instrument according to claim 25, characterized, that the means of measuring the time of the attack is a Device according to one of claims 16 to 19. 27. String instrument according to claim 26, characterized in that
that the strings ( 20 ) are electrically conductive and electrically insulated from one another, and
that the bridge of the string instrument ( 1 ) is made of electrically insulating material. 28. String instrument according to one of claims 25 to 27, characterized, that the means for measuring the direction of attack a Device according to one of claims 20 to 22. 29. String instrument according to one of claims 25 to 27, characterized in
that the means for measuring the direction of the stop is an ultrasound or microwave component ( 70 ) with transmitter ( 71 ) and receiver ( 72 ) for Doppler speed measurement,
that the component ( 70 ) is positioned on the stringed instrument ( 1 ) such that the transmitter ( 71 ) points in the direction of the plectrum ( 10 ) or the hand and the ultrasound or microwaves reflected by the plectron ( 10 ) or by the hand - Intensity hits the receiver ( 72 ) of the component ( 70 ). 30. String instrument according to one of claims 25 to 27, characterized in that the means for measuring the direction of attack is a video camera which is directed at the plectrum ( 10 ) or the hand. 31. String instrument according to one of claims 25 to 27, characterized in that the means for measuring the stop direction is at least one piezo pressure sensor which is arranged in the bridge, in the bridge or in the saddle of the string instrument ( 1 ) or in the plectrum ( 10 ) is. 32nd arrangement
with the stringed instrument ( 1 ) according to any one of claims 25 to 31 and
with a synthesizer that can be controlled by the determined direction of attack.