DE2535181A1 - ELECTRONIC MUSICAL INSTRUMENT - Google Patents

Description

July 30, 1975 9700-75 Dr.ν.Β / Ε

PATENT LAWYERS DR. ING. ERNST SOMMERFELD

DR. DIETER V. BEZOLD DIPL. ING. PETER SCHÜTZ DIPL. ING. WOLFGANG NEUSLER

D-8 MUNICH 86

PO Box 8Θ0ΘΘ8

TELEPHONE Ο89 / 47β90β 476819

TELEX 022038 TELEGRAM SOMBEZ

CMB Colonia Management and

Consulting company mbH & Co.KG 5000 Cologne 41, Schumannstrasse 22

Electronic musical instrument

Electronic musical instruments have already been proposed in DT-OS 2 515 524, the preferred ones Embodiments based on those specified by SCHUMANN Tone color laws and principles work as they are e.g. in DT-OSes 2 041 396, 2 041 426, 2 041 429 and 2 220 are set out. With the proposed electronic musical instruments, especially the sounds of wind instruments imitate very lifelike, this is especially true for embodiments of the proposed electronic Musical instruments in which the amplitude of the sound signals controlled in pitch by a keyboard is controlled by means of a air flow generated by the player is determined.

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With the proposed devices for electronic sound generation, the sounds can in principle also be generated imitate string instruments, with regard to the imitation of the fine modulatory characteristics that are characteristic of string instruments Processes and transient processes, however, the proposed devices can still be improved.

The present invention is accordingly based on the object of specifying an electronic musical instrument, with which the sounds of string instruments can be faithfully reproduced without the need for playing a real string instrument is required.

This object is achieved by the invention which is protected in the patent claim.

In the present electronic string instrument, the player is faced with the problems of intonation and the well-groomed stroke more or less largely decreased, while the modulation ability of the tone is retained; Stroke variants including pizzicato, vibrato and the intensity and timbre dynamics characteristic of string instruments can therefore be reproduced lifelike.

In the following an embodiment of the

The invention is explained in more detail with reference to the single figure of the drawing, with further features and Advantages of the invention come up for discussion.

The embodiment of an electronic string instrument shown schematically in the drawing according to the invention contains a single string 10 which is fastened at the ends as in a real musical instrument and between their ends via a saddle 12 and a web 14

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is excited. Length, tension and type of string 10 are here In contrast to a real musical instrument, relatively insignificant, since the string has no direct influence on it has the fundamental frequency of the sounds produced by the electronic string instrument.

In the illustrated exemplary embodiment, there are each a mechanical-electrical device in the saddle 12 and in the web 14 Converter 16 or 18 installed. In addition, the saddle and bridge or 14 are provided with damping material 20. Also the fastening devices Vibration damping (not shown) can be provided at the ends of the string.

The player can play the string 10 by bowing it with a bow or by plucking it into elastic transversal vibrations be stimulated. The location of the excitation is usually not in the middle between the saddle and the bridge, but rather closer to the bridge and has a certain influence on the character of the sound produced.

In the case of the illustrated electronic string instrument, the transducers 16, 18 not only provide information with respect to the amplitude of the string oscillation which the Volume of the generated sound corresponds, gained, but also information that depends on the type of excitation of the string and relates to the finely modulatory processes of the sound produced.

In the present electronic string instrument, the pitch is made independent of the string Control device 22 controlled, which is a keyboard, a key manual or a tape manual with or without frets can act. The controller 22 controls the frequency

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a sound signal generator 24 which supplies, for example, a raw sound signal consisting of a sequence of square-wave pulses can. The amplitude of this raw sound signal is through an amplitude modulator 26 modulates and then it passes through a pulse shaping circuit 28 and a Filter circuit 30, which gives the sound signal the final amplitude / frequency characteristic to lend. It can then be adjusted to the required power by a power amplifier 32 are amplified and reproduced through a speaker system 34.

When the string 10 is excited by bowing or plucking at a point indicated by an arrow 36 then, under idealized conditions, there is a triangular deflection of the string, as indicated by the dashed line Line 10 'is shown. A division ratio a / A of the web-side part is established by the excitation location 36 defined to the saddle-side part of the string. If the string is released, the string tension is known to endeavor to pull apart the kink at the point of excitation and kinks run at the speed c of String waves in the direction of saddle 12 and bridge 14 (see e.g. F. Trendlenburg "Introduction to Acoustics", Berlin 1962, page 74).

on

Since the / by the saddle 12 and the web 14 boundaries of the oscillating length L = A + a of Forces exerted over time by the time functions of the direction of pull or the angle to the string Limitations or support points, which limit the oscillating length of the string, are determined, can be the time functions derive the forces from the spatial function of the string by differentiation. That means, however, that the division ratio a / (A + a) of the string that, in its effect on the sound spectrum, is already qualitatively based on YOUNG's law

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is described on the envelope of the amplitude / frequency function of the sound has an equivalent effect as the duty cycle "Γ" / Τ of pulse trains with the period T and the pulse duration T *.

The information regarding the division ratio a / (A + a) is obtained in the illustrated embodiment of the invention by means of the two converters 16, 18, which are connected via decoupling resistors 38, 40 to a circuit arrangement 42, which is e.g. switched flip-flop circuit and an integrator integrating the output signal of the flip-flop circuit and supplies a DC voltage proportional to the division ratio to the sound signal generator 24, which determines or influences the pulse duty factor of the generated sound signal pulses in this.

With a real string instrument, the painting point is not changed when the different basic pitches are produced, as long as no tonal or dynamic change is intended. This means that the pulse duration V remains essentially constant for the tones of different pitch played on one string. When the string length L = A + a is shortened, the painted area, i.e. the point of excitation 36 and thus a, consequently also it * = 2a / c, is essentially retained, while T = 2 (A + a) / c with A is reduced accordingly. (σ is the speed of sound of the transverse wave propagation on the string.)

In the case of a string change on strings of the same length of a real stringed instrument, tuned to a fifth spacing there is a sudden shortening of ^ im Ratio 3j2 »see B. at the transition from the G to the D string:

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2a / c _G

c _D / c _G = 3/2

In the present electronic string instrument, in which a single string, in which no shortening is provided by handles, or another "string or plucking converter" is used, is made from the The above reasons preferably the pulse duration C derived from the transducer in certain pitch ranges corresponding to a The range of the period T determined by the control device is kept constant and, in the case of tone range limits, at a fifth distance, which correspond to a string change, changed by leaps and bounds in a ratio of 3: 2. This is done by coupling the Control device 22 with circuit arrangement 42.

The amplitude information of the vibrating string 10 can be obtained from the output signal of the transducer 18, for example Low-pass filter 44 can be obtained, the pass band of which is substantially below the natural oscillation frequency of the string 10 changes. The output signal of the low-pass filter 44 is fed to a modulation signal input of the amplitude modulator 26.

Information relating to the excitation of the string can also be taken from the vibrating string 10, that is, information that goes back to the forces acting on the strings when they are plucked or struck. This information can, for example, also be obtained from the output signal of the converter 18 through a high-pass filter 46, whose pass band begins above the natural oscillation frequency of the string and therefore only higher frequencies that are finely

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-7-modulatory processes affect, lets through.

In the amplitude modulator 26 or elsewhere, a threshold value element can be provided that the Sound signal channel blocks as long as the amplitude of the string oscillation does not exceed a predetermined threshold value. The sound generation therefore only begins when the string is bowed or otherwise stimulated.

The transducers 16, 18 can respond to pressure or acceleration or consist of microphones. Under Under certain circumstances, a single converter is sufficient, which is then preferred is arranged on the web 14. You can also use a strain transducer 48 instead of the transducer, but must then account for the fact that this is a signal of twice the frequency as one more responsive to the deflections of the string Converter emits.

The string 10 is preferably in one with

Däfgsmaterial provided housing housed, which is closed except for a cutout for the excitation to the to keep acoustic feedback of the electronically generated sounds on the string low.

The one corresponding to the amplitude of the string oscillation The output of the low pass filter 44 is preferred also fed to the sound signal generator 24 in order to influence the pitch to a small extent, namely the Pitch slightly reduced with a larger amplitude than with a real stringed instrument.

The electronic string instrument may have a register like the proposed electronic musical instrument 50 which are the parameters of the various

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Circuit arrangements, in particular the sound signal generator 24, the pulse shaping circuit 28, the filter circuit 30 (which can contain a formant filter) and the circuit arrangement 42 influencing the pulse duty factor allowed.

The embodiment described can be modified in various ways without the scope of Invention to exceed. For example, the "Streichwandler" can be a non-oscillatory resistance wire, rod or contain a lamellar contact path with intermediate resistors, which is painted with an electrically conductive sheet. the The painted area can then be determined by the resistance ratio between the arc and the ends of the resistance wire, etc. while the bow pressure and the amplitude by the contact resistance or by a train responding Converter in the arc is determined.

- In yet another embodiment of the Streichwandler's bow pressure and bow speed are influenced by the contact pressure and the lateral forces appealing bracket detected with appropriate transducers for the two force components. The painting site can be in this Trap can be determined optically or mechanically. In the latter case, the sheet can be movable in a guide, for example, which the sheet position via a variable resistor or the like. Detected.

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Claims (8)

9700-75 Dr.ν.Β / Ε Claims . ^) Electronic musical instrument with a circuit arrangement for generating sound signals with an amplitude / frequency characteristic corresponding to a predetermined pitch and volume impression, and with two control devices operable by the player, one of which controls the pitch and the other controls the volume of the sound signals, characterized in that the volume control device contains a component (10) which can be deflected by brushing by means of a bow or plucking and which is coupled to at least one mechanical-electrical converter (16, 18, 48), the output signal of which influences the volume of the sound signals. 2. Electronic musical instrument according to claim 1, characterized in that that the deflectable component (10) is a vibratingly mounted string and that the transducer (18) via a frequency-selective Arrangement (44, 46) which blocks the natural frequency of the string (10), with an amplitude modulator (26) for the sound signals are coupled. 3. Electronic musical instrument according to claim 1 or 2, characterized in that that the frequency-selective arrangement has a passage area below the natural frequency of the string (10). 4. Electronic musical instrument according to claim 2 or 3, characterized in that 709808/0477 net that the frequency selective arrangement has a passband above the natural frequency of the string (10). 5. Electronic musical instrument according to claim 1, 2, 3 or 4, characterized in that that the amplitude of the deflection of the deflectable ble component (10) corresponding output signal of the converter a circuit arrangement (24) is supplied which slightly increases the pitch of the sound signals in the case of large deflections belittles. 6. Electronic musical instrument according to claim 2 or claim 2 and one of claims 3 to 5, characterized in that with the or a circuit arrangement (38, 40, 42) for the transducers (16, 18) for obtaining a location corresponding to the excitation location (36) of the string Signal are coupled and that this excitation location signal a circuit arrangement for influencing the Frequency spectrum of the sound signals is supplied. 7. Electronic musical instrument according to claim 6, d a d u r ch characterized in that the Circuit arrangement for generating sound signals a sound signal generator (24) delivering a pulse-like signal contains and that the excitation location signal influences the pulse duration. 8. Electronic musical instrument after one of the preceding claims, characterized in that the circuit arrangement for generating of sound signals that deliver a pulse-shaped sound signal Sound signal generator (24) contains and that the sound signal generator contains a circuit arrangement which the pulse duration changes more or less abruptly at given frequency intervals (e.g. at intervals of a fifth). 709808/0477