EP0309632B1 - Synthesizer control system using a bowed string musical instrument - Google Patents

Abstract

A pickup assembly is used with a string instrument having a plurality of strings and an elongated fingerboard against which the strings can be stopped, a bow having a filament adapted to be drawn across the strings, and a frequency synthesizer. The assembly is composed of a pickup on the fingerboard for detecting which strings are stopped, where therealong, and for generating an output corresponding thereto, a pickup connected to the bow for detecting action thereof for generating an output corresponding thereto, and a pickup connected to the strings for detecting which string is being contacted by the bow and for generating an output corresponding thereof. These resultant, mainly analog signals are then fed to a processor that is connected to all of the pickup for receiving the outputs thereof, digitizing these outputs, and feeding the digitized outputs to the synthesizer.

Description

The present invention relates to a device intended for controlling a frequency synthesizer from a bowed musical instrument, such as a violin.

US Patent 3,742,114 describes a device of this type, suitable for a kind of guitar, which controls the frequency synthesizer by means of means for detecting the position of the fingers on the key of the instrument and for detecting the string or strings that are played.

In terms of connecting a synthesizer to a violin, the devices currently known, described in particular in French patent application No. 2 444 312, generally consist of a microphone which is fixed on the bridge and which captures its vibrations. mechanical. The sound picked up by the microphone is filtered, so as to isolate the fundamental component, and the signal obtained is applied to the synthesizer, which itself provides sound as an output according to the characteristics which have been programmed.

Such a device is rather suitable for monophonic instruments, but not really for the violin, of which it cannot reproduce the "glissando" mode, nor generally the sounds rich in harmonics, obtained among other things when playing several notes simultaneously.

The present invention relates to a device for adapting a violin, or other bowed string instrument, to a frequency synthesizer, which does not have this type of drawback. It is characterized in that it is equipped with means for detecting the position of the fingers on the fingerboard of the instrument, means for detecting the instantaneous characteristics of the movement of the bow, and means for detecting the string or strings which are played.

Advantageously, these means are constituted by a means of capturing the pressure of the bow on the strings played, a means of capturing the speed of the bow on the strings played, means with an electrical contact tablet to determine the position of the fingers on the fingerboard, and means by electrical contact between the bow and the strings to determine the string or strings which are played.

The analog electrical signals at the output of these different means are digitized and applied to a programmed logic processing unit, the output of which is then applied to the frequency synthesizer.

Thanks to the device of the invention, the game can be acoustically mute, the bow being "smooth", which makes it possible to play "in silence", the sound being heard on headphones by the artist alone, via the synthesizer. The device also makes it possible, after analysis, to opt for a "glissando" or discontinuous mode, and this at will, which, by making it possible to correct the positioning errors of the fingers by the beginner, considerably facilitates the learning of the violin.

The device of the invention can be mounted directly on a traditional violin without altering the acoustic qualities, the bow however being different from the simple bow normally used for this violin. A traditional violin thus equipped becomes normally sound again at will by using its original bow normally coated with rosin.

• Figure 1 est une vue d'ensemble schématique du dispositif de l'invention,
• Figure 2 est une vue agrandie et partielle de l'archet apparaissant sur la figure 1,
• Figure 3 est une vue partielle déployée et éclatée de la partie du violon, apparaissant sur la figure 1, qui est équipée d'une partie du dispositif de l'invention.
• Figure 4 est une représentation électrique par schémas blocs de l'unité de traitement de l'information équipant le dispositif de la figure 1.

The invention will be better understood with the aid of the following description of an exemplary embodiment, with reference to the appended drawings in which:

• FIG. 1 is a schematic overview of the device of the invention,
• FIG. 2 is an enlarged and partial view of the bow appearing in FIG. 1,
• Figure 3 is a partial deployed and exploded view of the part of the violin, appearing in Figure 1, which is equipped with a part of the device of the invention.
• Figure 4 is an electrical representation by block diagrams of the information processing unit equipping the device of Figure 1.

Referring first to the schematic overview of Figure 1, the reference 1 designates a standard violin, equipped in accordance with the invention, and the reference 2 designates its bow, also equipped according to the invention. Block 3 is a frequency synthesizer, of a commercially available model, equipped with a signal input socket 4 with MIDI standard, and block 5 comprises the power supply circuit and the logic processing board. information coming from the violin 1 and the bow 2, the output of block 5 being effected, by a cable and a MIDI connector 7, towards input 4 of block 3, and its DC voltage supply at 5 volts carried out from the outside by a cable 8.

Upward 9 of the bow 2 is fixed a multi-socket base 10, on which is plugged a socket 11 connected to the block 5 by a cable 12. On the rod 13 of the bow is fixed, about two thirds of its length from the rise, a strain gauge 14 intended to measure the pressure of the bow on the played string, or on the played strings. The usual horsehair wick is replaced by a bundle 15 of conductors of high electrical resistance, such as a set of fifty silicon carbide wires of 1000 ohms of resistance per centimeter of wire, the DC voltage of 5 volts being applied between the two ends of the horsehair wick 15, as will be described in more detail below.

The heel 16 of the violin is equipped, at the rear part of the violin, therefore on the back of said heel, with a multispindle base 17, on the side of which a multiple socket 18 is plugged in, conveying towards the block 5 and by a common cable 19 ten signals, including eight analog signals and the continuous supply at 5 volts. These signals come from above the key 20, using a connecting cable 21, as will be detailed below.

Referring now to FIG. 2, the bow 2 is represented, with its strain gauge 14 and its bundle of resistive horsehairs 15. The downstream end 22 of the drill bit 15 is connected to the positive terminal of the voltage d 'supply by a first wire 23 running along the rod 13 of the bow, while its upstream end 24 is brought to its negative terminal by a second wire 25. The strain gauge 14 has its supply terminal connected by a wire 26 at the positive terminal, and its output terminal connected to one of the pins of the socket 10 by a wire 27. As shown in dotted lines, it is also possible, and advantageous, to have under the rise 9 a " pizzicato finger "240, in metal for example electrically connected between 25 and 24: by contact on a string, a maximum electrical value is then transmitted, the analysis taking into account only the rising edge of the signal obtained.

When the bow presses on a metal cord 28, a first electrical information is emitted at 29 by the strain gauge 14, giving the value of the pressure on the cord, and the cord 28, which serves as a cursor for the potentiometer constituted by the bundle of horsehair 15, makes it possible to take an electric voltage representative of the instantaneous value of the position of the bow relative to the string 28, and also representative of the fact that the string 28 is played.

• une information représentative de la pression de l'archet sur la corde,
• une information lui indiquant la ou les cordes qui sont jouées,
• une information représentative de la position instantanée du faisceau de conducteurs 15 sur la ou les cordes jouées : deux informations de ce type relevées en deux temps successifs définis permettront par exemple au bloc 5 de calculer la vitesse de déplacement de l'archet sur la corde 28.

Thanks to the bow, the logic analysis block 5 therefore already receives:

• information representative of the pressure of the bow on the string,
• information indicating the string or strings that are being played,
• information representative of the instantaneous position of the bundle of conductors 15 on the string or strings played: two pieces of information of this type recorded in two defined successive times will, for example, allow block 5 to calculate the speed of movement of the bow on the string 28.

Referring now to FIG. 3, the reference 30 designates a thin strip of plastic material the part of which between A and B is intended to be glued to the fingerboard, A being at the level of the violin neck and B at the level of the the cantilevered end of the key, as indicated elsewhere in FIG. 1.

On the thin strip 30 are deposited four tracks 31-34 of a resistive conductive element, such as carbon, these four tracks being longitudinal and placed exactly respectively under each of the four strings of the violin, directly above them. The four carbon tracks 31-34 are short-circuited at their two ends by transverse strips 35,36 of conductive ink, the strip 35 being connected by the conductive connection 37 to a terminal 38 receiving the positive polarity of the supply. continuous of the assembly, and the strip 36 being connected by the conductive connection 39 to a terminal 40 receiving the negative polarity.

The part of the plastic strip 30 between B and C is glued on the underside of the key going up to the handle, that is to say on the face of the key opposite to that receiving the part AB, and the part between C and D is glued to the side of the heel 16 of the violin (see FIG. 1), the terminals 40 and 38 forming part of the multi-pin outlet socket 17, and the conducting wires 37 and 39 forming part of the connection cable 21 shown in Figure 1.

The carbon tracks 31-34 form the input elements of an electrical contact tablet intended to determine the position of the fingers on the strings. Such a contact pad, if it is new in the application to the present invention, is not new in itself in principle, and there have been many examples on the market for a long time, in particular applied to paintings. indicators of bus networks, commuter trains, or the like.

The outputs of this contact pad consist of four conductive lines 41-44 which are positioned above each of the four corresponding tracks 31-34, with a spacing of a few tenths of a millimeter. In the embodiment of Figure 3, these four lines 41-44 are deposited on the underside of a strip 45 in material semi-rigid plastic, therefore having a certain flexibility, and this sheet is placed on the part AB of the key and on the strip 30. An intermediate strip 46, disposed between the plastic strips 30 and 45, hollowed out facing the tracks of carbon 31 to 34, allows the maintenance of the spacing mentioned above. Beyond the end B, all the conducting wires 37, 39, 41 to 44, 49 to 52, are taken "sandwiched" between two sheets of plastic material, not shown, until the outlet socket 17. Of course . between B and C, and up to tap 17, the strip 45 is glued to the strip 30.

We can easily see that when we press, by the finger and the corresponding rope, on the strip 45, between A and B, at a point of a line 41-44, we create the electrical contact at this point with the track of carbon and a potentiometric voltage take is made on said corresponding track 31-34, which appears on take 17 by the corresponding line 41-44, the finger, by its support, serving in a way as a cursor, potentiometer and the wires 41-44 of output wires.

Furthermore, on the two longitudinal sections of the violin fingerboard are stuck two lateral flaps 47, 48 of the plastic band 45, which each have two longitudinal conducting lines - respectively 49.50 and 51.52 - which are each connected to their end of side A, that is to say towards the saddle of the violin, electrically connected respectively to each of the strings of the violin, beyond the saddle, using small alligator clips not shown. These lines 49-52 serving as the electrical connection point of the played string 28 (FIG. 2), relative to the bundle of resistive hairs 15 of the bow, as explained previously with reference to FIG. 2. Beyond from B, these lines 49-52 are part of the bundle of data wires joining the output socket 17 of the violin.

• les deux bornes d'alimentation 38 et 40 en cinq volts continu,
• huit bornes 53-60 fournissant quatre informations potentiométriques issues du faisceau de crins 15 de l'archet, représentatives de la position instantanée de l'archet par rapport à la ou aux cordes jouées, ainsi que quatre autres informations donnant, par mesure potentiométrique de tension, la position des doigts appuyant sur les cordes.

The output socket 17 therefore has ten useful pins:

• the two power supply terminals 38 and 40 at five volts DC,
• eight terminals 53-60 providing four potentiometric information coming from the hair bundle 15 of the bow, representative of the instantaneous position of the bow relative to the strings played, as well as four other pieces of information giving, by potentiometric measurement of tension , the position of the fingers pressing on the strings.

FIG. 4 gives a nonlimiting example of a device for analyzing and processing the information provided by the violin 1 and its bow 2, and appearing at the output sockets 10 and 17, from which they are conveyed by cables 12 and 19 to box 5 containing the logic board according to this figure 4.

In FIG. 4, the reference 61 designates a microprocessor processing the information in accordance with the programmed operating data included in a memory 62, of the read-only type, known as R.O.M. The eight data coming from terminals 53 to 60 (FIG. 3) enter on the card at 63, on an analog multiplexer 64, whose analog multiplexed output is applied, by connection 65, to an analog-digital converter 66 outputting the bits correspondents in parallel through connections 67 to an input of a peripheral interface adapter, or PIA, 68. The PIA 68 receives, via the bus 69, on its input 70, data coming from the microprocessor 61, and it sends on its output 71, by the wires 72 and 73 respectively, counting and reset pulses to the two inputs corresponding to a counter 74 providing on its three outputs 75, 76 and 77, three address bits to the analog multiplexer 64.

Similarly, the information coming from the strain gauge 14 (FIG. 2) arrives via the wire 29 (FIG. 2) on the input terminal 78 of the card shown in FIG. 4. This information is applied, via a connection 79 to an analog-digital converter 80, from which it leaves digitized on the data bus 69 connected to the microprocessor 61, as shown in the drawing.

On the logic card of FIG. 4 is still applied, on the input terminals 81, 82, the DC supply voltage, which supplies the various circuits of the card and is found at 83 and 84 to supply the terminals d end 22 and 24 (FIG. 2) of the bundle of hairs 15 of the bow 2.

The output information from the microprocessor 61 is applied, via the bus 85 to an asynchronous communication interface, or ACIA, from which it leaves in series on the wire 6 (see also figure 1) and the socket 7 in MIDI standard, this socket being intended to be connected to the input terminal 4 of the synthesizer 3.

The invention is of course not limited to the embodiment which has just been described. Other similar capture means could for example be used, such as an accelerometer on the bow, and another form of tactile contact tablet on the violin key. It obviously applies to all kinds of bowed string instruments other than the violin, cited here only as an example. A part of the logic board, or all of it can be placed on the violin itself, advantageously under the key on the back of it, there being enough space there. We can place at this location only the part D ′ (figure 4) of the logic card, while the remaining part E would then remain in the housing 5, but we can also place the whole card D ′ + E there, in which case we would no longer have on the violin except the output 7 to the synthesizer, the inputs 81 and 82 of supply voltage, and the terminals 83, 84 supplying the bow.

Claims (7)

1. A device for controlling a frequency synthesizer by a bowed stringed musical instrument, comprising:
      means for detecting the position of the fingers on the finger board of the instrument,
      means for detecting the chord or chords which are played, characterised in that it includes:
      a bow (2),
      means (14, 15) for detecting the position or acceleration of the bow (2) in such a manner that a processing unit (5) can calculate the instantaneous speed of the bow (2),
      means (14) for detecting a strain on the bow, of which the amplitude is a function representative of the application pressure of the bow (2).
2. A device according to Claim 1, characterised in that the electrical signals emanating from the different means are digitised and applied to a programmed logic processing unit (5), of which the output is then applied to the frequency synthesizer (3).
3. A device according to claim 1 or Claim 2, characterised in that said means include means having an electrical contact board (30) to determine the position of the fingers on the finger board, and means (49, 52) using an electrical contact between the bow and the strings to determine the string or strings being played.
4. A device according to Claim 3, characterised in that said electrical contact board (30) is placed on the finger board (20) of the instrument.
5. A device according to one of Claims 1 to 4, characterised in that it includes an input and output signal connector (17) on the instrument (1), which is placed behind the heel (16) or the latter.
6. A device according to Claim 2, characterised in that at leapt a part of said logic unit is positioned on the instrument itself.
7. A device according to Claim 6, characterised in that said logic unit (D' + E) or said part (D) of the latter is positioned on the back of the finger board (20) of the instrument.

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