EP1285431B1 - Instrument and method for producing sounds - Google Patents

Abstract

An innovative music instrument ( 101 ) comprises at least one tunable string ( 102 ), a holding device ( 106 ) for holding the at least one string ( 102 ), an electrically or electronically operated exciting device ( 116,116 ') for contactlessly exciting of the at least one string ( 102 ), a sounding body ( 108 ) for acoustically radiating oscillations of the string and an interface ( 113 ) for supplying a signal to the exciting device ( 116, 116 '), wherein the signal is produced independently from the at least one string ( 102 ). The exciting device ( 116, 116 ') enables exciting oscillations of the string of a sufficiently large amplitude so that the sounding body ( 108 ) can radiate tones of a loudness which is at least in the range of known acoustical string instruments. For transferring the string's oscillations to the sounding body ( 108 ), a bridge ( 112 ) is arranged between the sounding body ( 108 ) and the at least one string ( 102 ) . The electro-acoustical music instrument ( 101 ) has the quality of resonance capability and of discrete overtones, and enables a synthesis of an acoustical sounding beauty with electronic flexibility.

Description

The present invention relates to a musical instrument, an excitation device for non-contact excitation of at least one strained string with magnetizable material, as well as to a method for generating sounds.

The known musical instruments can basically be divided into two groups, namely acoustic and electrical, in particular electronic, instruments. The acoustic instruments radiate the tones or the sound at a sufficiently high volume, so that a piece recited with an acoustic instrument is heard by the listeners. The acoustic stringed instruments comprise strings for generating and emitting a sound, a tensioning device for the string and a sounding body, wherein the strings are mechanically vibrated, the string vibrations are transmitted to and radiated from the sounding body. The various stringed instruments each have their characteristic sound characteristics, which depend on the strings, the tensioning device, the sounding body and the mechanical excitation. The electrical or electronic instruments generate an electrical or electronic signal, which is supplied via an amplifier to a speaker and emitted by the speaker as a sound signal. To play an electric instrument, for example, a keypad or a keyboard is provided. The keys can directly trigger an electrical signal and / or excite a physical system from which at least one parameter is tapped and converted into an electrical signal. Such a physical system may be used to detect a strike characteristic. Synthesizers have many possibilities for changing the signal. In electric guitars and electric basses, the physical string vibration is stimulated mechanically and recorded by a pickup and fed via an electrical or electronic circuit to a speaker. Midi devices, such as a Midisax, can also be used to generate electronic sound signals. A Midisax recorded in addition to the handle and the air flow and optionally a force that acts from the lips on the mouthpiece, in particular on a leaflet. The recorded parameters allow the generation of a signal which, in addition to the pitch and the length of the sound, also the dynamics of the volume and optionally further sound properties The sound quality of an electric instrument always depends on the circuit used and the connected speaker.

From the Scriptures FR 2 315 740 a device is known in which a plurality of tensionable, equal length strings are each excited by an electromagnetic excitation element without contact. In order to be able to vibrate the strings with changing magnetic fields, the strings are made of magnetic material. The strings are arranged between two plates, wherein the plates are held by a cylindrical base at a predetermined distance from each other. Each excitation element is fed with a frequency, so that each string is excited and oscillates with your, corresponding to the respective string voltage, fundamental frequency. To feed the excitation elements a multivibrator with adjustable frequency is used. To make the vibration of a string audible, this is removed with a pickup and the resulting electrical signal is fed via an amplifier amplifier to a speaker. The sound generated by such a device results as a superposition of the fundamental vibrations of the clamped strings. It is therefore only a sound source and not a playable instrument. In addition, the sound quality is limited by the speaker.

The WO 98/28732 describes an automatically tunable electric guitar, in which the strings to be tuned electromagnetically excited and the string tensions are adjusted with an automatic tensioning device. The excitation of each string is done with the frequency of the desired fundamental and the effectively occurring string vibration is picked up with a pickup, so that the signal for the adjustment of the difference between the desired and the tapped frequency can be determined. The amplitudes needed to tune are very small. The electromagnetic excitation device uses the strings with a simple electromagnet in barely audible vibrations.

The EP 0 539 232 describes a solution for increasing the duration of oscillation of a mechanically excited string of an electric stringed instrument. For this purpose, the frequency of the excited oscillation is picked up with a pickup. The signal of the pickup is amplified and supplied to an electromagnetic excitation device, which keeps the string in vibration. The US 5,070,759 also describes a solution to Extending the oscillation period of a mechanically excited string. It is proposed to use the excitation device as a pickup. In both solutions, the signal used for the excitation comes from the string itself and to produce the audible tone, the tapped signal is fed via an amplifier to a speaker. The described excitation devices are each on one side of, or under, the guitar strings, so that the strings from the other side, or from above, are freely accessible. The excitation devices each comprise at least one coil and parts of magnetizable and / or parts of magnetic material. Each coil extends over the entire area with strings. In order to stimulate the strings sufficiently, coils with thicker wires and higher number of turns are used in comparison to the pickups. In addition, examples are described in which the magnetic field density is different for the differently thick and differently tensioned strings. For this purpose, the arranged in the coil magnetizable material is divided with slots in different, the respective strings associated areas, or the strings are assigned different permanent magnets. In the known excitation devices, the electromagnetic field used for the excitation always extends over the entire range with all strings. If the signal comes from just one string, only a small portion of the exciting field is used to excite this string. The efficiency of this excitation device is extremely small and it can only be achieved weak excitations, which are emitted acoustically via an amplifier and a speaker.

In Audio frequency measured by the electrically excited monochord; Emrys Williams; University of Liverpool; June 1934 describes a monochord with a steel side, a sound board and a magnetic system with magnetic coils, the coils with a variable frequency alternating current stimulate the string. Effective resonant frequencies are determined by balancing the excitation frequency and the resulting vibration modes by counting the nodes of vibration. Also US 5,874,685 describes a monochord for measurement purposes. With the measuring arrangement longitudinal vibrations are to be detected. An efficient stimulation and emission of sounds, as it is necessary for an acoustic instrument, is not revealed.

Both the acoustic and electric musical instruments have their respective limitations. In the case of the acoustic instruments, the generation of the sounds is limited to the corresponding operation of the instrument by a player. For the electric instruments, the limitation is given by the use of a required speaker. The known excitation devices for exciting string vibrations with electromagnetic fields only make vibrations with small amplitudes achievable.

The invention is due to the limitations of the known instruments, the task of finding an instrument that has fewer restrictions and thus opens up new possibilities.

This object is solved by the features of claims 1, 12 and 13. The dependent claims describe alternative or preferred embodiments.

In the solution of the problem has been recognized that an inventive stringed instrument the sound quality of an acoustic string instrument with the diverse control by an output of an electrical or electronic instrument or device, in particular a synthesizer, keyboard, computer, midi device, a microphone or any speaker output, should connect. In the known acoustic stringed instruments, the strings are excited by striking, plucking or brushing, whereby the strings are vibrated due to the mechanical excitation of natural oscillations or resonances with the corresponding overtone components. The overtone spectrum plays an important role for the timbre, but can not be controlled, or only limited, by the mechanical stimulation. If now in the inventive string instrument instead of the mechanical excitation of the strings an advantageous, non-contact excitation, in particular with excitation frequencies in the entire audible frequency range, is used, the overtone spectrum of the strings can be stimulated controlled. It can therefore be used to control the inventive string instrument signals that directly stimulate overtones with selectable intensities, which is not possible with a mechanical excitation. In the case of acoustic instruments, when playing notes with harmonics, after the stimulation of the root note, the root note is muted so that the overtones become audible. In this case, an overtone can never sound in the same quality or as a sine tone, as when it is excited directly with the inventive instrument. The number of overtones increases strongly towards high notes, so over the root note in the second octave 2, in the third octave 4, in the fourth octave 8 and in the fifth octave 16 overtones playable. Only a part of these overtones corresponds to a tone of the tempered tuning, namely in the second octave 2, in the third octave 3, in the fourth octave 5 and in the fifth octave 7. In an acoustic musical instrument, the phenomenon of the momentum of the sound unfolds important role, which should not be the case with a loudspeaker.

An instrument according to the invention comprises at least one tunable string, a holding device for holding the at least one string, an electrically or electronically operated excitation device for non-contact excitation of the at least one string, a sound body for acoustically emitting the string vibration and an interface for supplying a signal for the excitation device, wherein the signal is generated independently of the at least one string. The excitation device makes it possible to excite string vibrations with sufficiently large amplitudes so that the orchestra can emit notes at volumes at least in the range of known acoustic string instruments, the volume ranges for large volumes preferably extending beyond the maximum volumes of known acoustic string instruments. For transmitting string vibrations to the sound body, at least one transmission element, preferably a web, is arranged between the sound body and the at least one string.

The inventive electro-acoustic musical instrument has the quality of the resonance capability, or discrete harmonics, and allows a synthesis of the acoustic sound beauty with the electronic flexibility. With the non-contact excitation of the strings of an acoustic instrument, an effect is achieved which goes far beyond the electrical control of a mechanical excitation device. It is not the known style of playing an acoustic aspired, but a new instrument provided, which overcomes the limitations of the known instruments and devices.

For holding the at least one string, a holding device is provided, which preferably comprises two side parts and at least one support column, wherein the support column is arranged between the two side parts. The at least one string extends from one to the other side part and is connected at one end clamped to the side part. To be able to achieve loud sounds, it is expedient to stretch each metal string used with a clamping force in the range of 200 to 1000, in particular 300 to 700, preferably substantially 500N. If, for example, 24 strings are provided, the adhesive device has to bear clamping forces of up to 12,000 N. So that an extremely massive support column does not have to be used, if necessary a plurality of tubes and / or profiles are arranged substantially next to each other. In order to prevent that the holding device also vibrates due to the vibrating strings and generates unwanted noises, damping elements are assigned to the holding device. For example, hollow support columns at least in sections with rubber, especially hard rubber, stuffed or filled. It has been shown that the development of noise depends strongly on the two sides. If stabilizer ribs projecting from the sides are provided, these should be in pairs be formed and the gap should be stuffed or filled with rubber, especially hard rubber.

So that the blasting of the sounds is not affected by the support column, the sound body between the strings and the at least one support column is arranged. The string-facing surface of the sound body is formed by a membrane. To transfer the string vibrations to the membrane, a bridge is provided on the membrane over which the string is stretched. The sound body is formed separately from the holding device and is attached to this, that the possibility of vibration of the sounding body and in particular its membrane is not substantially affected by the holding device. The sound body can be formed by a flat membrane, which optionally has a shape deviating from a flat surface. Preferably, a hollow sounding body is used which comprises annularly arranged closed frames, wherein on one end side of the frames, the membrane and on the other end of a floor is fixed. Optionally, instead of ribs only ribs are attached to the membrane. It goes without saying that, if necessary, the adhesive device can also be formed by the sounding body, in particular its frame. However, the holding device must have a high stability in the case of a plurality of strings, in particular tensioned with high clamping forces, which is preferably achieved with a holding device separate from the resonator.

In order for the membrane to have particularly good vibration characteristics, it is made from tonewood with tight tree rings and connected to the frames in a prestressed state. In the tonewood, the tree rings are perpendicular to the surface of the wood surface, wherein the fiber direction of the sound wood extends in a first direction of the embran surface and follows in a second direction perpendicular to the membrane surface tree ring on tree ring. In the first direction, the membrane is less flexible than in the second. A flat membrane as a flexible surface in the untensioned state can not optimally absorb the vibrations that are transmitted to it via the web. Therefore, it is bent at least in the second, but preferably also in the first direction slightly and thus biased attached to the sides. The frames are curved at the membrane facing the end face according to the desired curvature of the membrane. Preferably, four frames are provided, which together form a rectangle. The first direction of the membrane extends in the direction of the longer side of the rectangle. The second direction of the membrane extends in the direction of the shorter side of the rectangle. Accordingly, the front sides of the shorter frames are more curved than the front sides of the longer frames. The membrane thereby receives the shape of a partial surface of a torus or a barrel body, said toroidal surface preferably protruding against the string and therefore radiates in a larger solid angle than a curved against the interior of the sound body surface. A sound body with the described prestressed membrane ensures a particularly efficient recording and acoustic radiation of the transmitted over the web string vibrations.

It goes without saying that the frames can be put together to another polygon, for example, to a rectangle without a right angle or a hexagon. The membrane receives a corresponding shape. Differently shaped sounding bodies may be desired due to a better radiation characteristic or due to a different appearance.

In order not to hinder the vibration of the membrane, at least one opening in the sound body is formed, through which an exchange of air from the interior of the sounding body is made possible to the environment. In order not to negatively change the stress distribution in the membrane through an opening, the at least one opening in the region of a frame is formed according to a preferred solution, so that the sound component exiting through the opening also extends into the half space adjoining the membrane or towards the front , exit.

When using only one string, only the tones of the overtone spectrum of this string can be emitted, which form a very limited sound spectrum, especially in the region between the fundamental tone and its second octave. In order to be able to play pieces written for known stringed instruments with the instrument according to the invention, a chromatically tuned set of strings is preferably used. For example, a single instrument with chromatic stringing over two octaves can be provided. For example, a single instrument with an alto and a bass octave would include strings in the tuning g-fis' and contra G to FIS. Preferably, however, register instruments with 12 strings each, which are chromatically tuned and comprise one octave, are built. The register instruments could be provided as soprano, alto, tenor, bass and contra-bass instrument. Because with the contactless If the harmonics of each string can be well excited up to high registers, one can already play with a single register instrument from the lowest note to very high registers in all 12 keys. In addition to the chromatic tones of the tempered mood, there is a multitude of overtones that can be adjourned, which makes it possible to produce the widest variety of special tone colors. In order to achieve the highest possible maximum stimulable volume, at least two strings are optionally used at least in individual strings-pitches. It has been shown, for example for bass strings, that the achievable volume doubles when using two strings led directly next to each other and stimulated by the same exciter. At higher altitudes, in particular alto and soprano situations, it may be expedient to associate each excitation device with three identically tuned strings.

A registeer instrument according to the invention comprises 5 to 6 octaves of tonal range due to the specifically playable overtones. A bass and an alto instrument together therefore already gives approximately the circumference of a grand piano. In contrast to the wing, mobility and weight are ensured with the instrument according to the invention. The register instruments can be arranged distributed in the space, whereby a multifunctional, open system is available in which the flexibility of the room design is also important.

An electronically operated excitation device for non-contact excitation of the at least one string preferably comprises an electromagnet on both sides of the at least one string. The known from the prior art excitation devices with the arranged only on one side of the string electromagnet can not ensure the preferred strong excitation forces, or high accelerations of the string, at least not with a reasonable Mregungsleistung. In a one-sided excitation device, the magnetic field energy can be used too less efficiently for the deflection or acceleration of the string. In order to efficiently use the magnetic field energy to accelerate a string, a system with two coils is used, with the string to be excited extending through an air gap between the two coils.

In order for the magnetic field of the coils to be able to exert a force on the string, current must either flow through the string or it must comprise magnetizable material. On a current-carrying string, the Biot-Savart force acts in a magnetic field perpendicular to the magnetic field and the string, so that a deflection of the string is expected transversely to the axis of the coils and thus in the longitudinal direction of the air gap. If the string comprises magnetic or magnetizable, in particular ferromagnetic, material, a deflection force can be transmitted to the string via a magnetic effect from the magnetic field. From the energy density of the magnetic field with the string, or from a Maxwell voltage of this system, results in the inhomogeneous field, a resultant force which alternately acts in opposite directions with the variable magnetic field. The deflection of the string takes place in the direction of the axis of the coils and thus alternately against each one of the coils, or transversely to the air gap.

wobei

• F: Kraft auf die Saite [N]
• i: Strom durch die Saite [A]
• I: Länge des dem Magnetfeld ausgesetzten Leiterabschnittes [m]
• B: magnetische Flussdichte [T]

With a current-carrying conductive string only a weak excitation can be achieved. The force acting on the flowed through string by the magnetic field can be formulated as follows: $$F=i\left(\overrightarrow{\mathit{l}}\times \overrightarrow{B}\right)$$

in which

• Q: power on the string [N]
• i: current through the string [A]
• I: length of the conductor section exposed to the magnetic field [m]
• B: magnetic flux density [T]

If the string and the magnetic field vectors are perpendicular to each other at the string, the following deflection force results: $$\mathit{F}\mathit{=}\mathit{ILB}$$

The required magnetic field is generated by two coils coupled in the same direction. There is no need for a permanent magnet. The string is located in the middle of the air gap, in which there is approximately a homogeneous field with field lines in the direction of the common coil axis. A changing force action is brought about by a changing magnetic field B or a changing current i through the string. With this principle, care must be taken to ensure that the flow of current through the string does not cause them to heat up. This would cause the string to expand and the instrument would be out of tune. At a maximum tolerable current flow through the string of i = 1A, a length of the magnetic encoder of 10mm and a desired force on the string of F = 0.1N requires a magnetic flux density in the air gap of 10T. This is realistically barely achievable, in particular with a required air gap of about 5 to 6 mm.

The calculation was confirmed with an experiment and a simulation. The force effect between a current-carrying string and a magnetic field can not be sufficient excitation of the string with reasonable effort. The achievable magnetic field flux density is not sufficient to deflect the string laterally. In addition, if the string is not perfectly centered in the air gap, an uncontrolled force will occur in the direction of the axis of the coils. This force has an oscillating component in the oscillating magnetic field, causing the string to vibrate. The string is also pulled against the closer coil and managed at too small a distance with this in contact. This is because the string is made of magnetizable material. If the magnetizable material of the string has a small remanence, or soft magnetic, the described attractive force will occur regardless of the current direction of the magnetic field.

In order to generate a sufficiently large excitation force with reasonable effort, a string is used which comprises magnetizable, in particular ferromagnetic, material, but preferably is formed from this. With at least one permanent magnet and two coils arranged on both sides of the string, a magnetic field which is inhomogeneous in the region of the string and therefore, as already mentioned above, a deflection force can be achieved. By way of illustration, it can be assumed that the at least one permanent magnet in the air gap and thus in the region of the string generates a strong magnetic field which assumes a kind of potential function. In order to set the string in oscillation in this permanent magnetic field, inhomogeneities in the magnetic field are generated by the coils in accordance with the excitation signal. The coils are wound in opposite directions and thus generate in a flow magnetic fields, which are each directed with the same poles against each other. In one or the other current direction, the total, given by the coils and the permanent field, magnetic field density is increased against one or the other coil out. The inhomogeneous magnetic fields in the air gap alternating according to the current direction act with corresponding forces on the magnetizable material of the string. If a current flows through the coils, the magnetic field in the air gap changes. Where the field generated by a coil has the same direction as the static field, If the flux density increases, the fields on the other side of the string will act, which leads to a weaker magnetic field. Because of this asymmetry, the string has a resultant force.

In order to provide the strongest possible permanent magnetic field, preferably two permanent magnets are used. In a first embodiment, the two permanent magnets are each arranged in one of the coils and thus on both sides of the air gap. However, this arrangement has the disadvantage that the permanent magnets are arranged where the electromagnets have the highest flux density, which can lead to demagnetization of the permanent magnets in strong alternating fields of the electromagnets. The electromagnets and the permanent magnets generate closed magnetic field lines, which experience a great resistance in the air gap and around the electromagnets in the air. Through the use of magnetizable cores, in particular of iron cores, which offer a closed path for the magnetic field lines up to the air gap with the string, the resistance of the magnetic fields, or the air fraction in which form the magnetic field lines and thus the resistance to the Magnetic field, be reduced. As a result, the field density in the region of the air gap can be increased. In addition, the permanent magnets can be inserted outside the coils in the closed path of the core part, whereby they are exposed to a smaller field density of the magnetic field generated by the coils. When designing, care must be taken that the field strength generated by the electromagnets in the case of the permanent magnets is smaller than the coercive field strength of the permanent magnets, so that their magnetization is not impaired. The resistance for achieving the alternating magnetic fields can be further reduced by forming the core part by abutting core sheets with electrical insulation, whereby the occurrence of eddy currents is reduced relevantly.

The superposition of the fields of the permanent and electromagnets creates an inhomogeneous field in the air gap with the string. The force effect of the inhomogeneous field on the string can be described from the Maxwell stress as follows: $$F=1/2\oint \overrightarrow{B}\overrightarrow{H}d\overrightarrow{A}$$

With an integration over a string enclosing the system boundary G, the force effect of the magnetic fields of the coils and the permanent magnets can be determined on the string. An estimate of the resulting force shows that this depends on the field strength of the permanent magnets and on the field strengths of the coils. By the use of Permanent magnets with high magnetic flux densities, the efficiency of the excitation device can be significantly increased. If the greatest possible amplitude of the string is to be achieved with a small active power supplied by the electromagnets, as high-quality permanent magnets as possible, for example samarium-cobalt (SmCo) or neodymium-iron-boron (NdFeB) magnets, must be used. The efficiency can be at least doubled compared to solutions with ferrite magnets. An advantageously usable permanent magnet must make possible the highest possible magnetic flux densities and must not be sensitive to external fields, or should have a sufficiently large coercive field strength.

To generate the inhomogeneity in the magnetic field, it would also be conceivable to use only one coil, but then the force acting on the string would be smaller with a constant coil current. With a higher coil current, a larger local heat generation would occur. In addition, could be achieved with only one coil on the remote side of this string, no analog inhomogeneity, as in the coil. Correspondingly, the excitation against the coil and the excitation from the coil would be different at the same current strength, which would cause asymmetric excitation when excited with a sinusoidal signal. Therefore, an excitation device having a symmetrical construction with respect to a median plane is preferred, the median plane passing through the axis of the string perpendicular to a common axis of the coils.

An excitation device with two E-shaped core parts, which are connected to each other in the outer two projections via a permanent magnet and each comprise a coil on the central projection, allows an extremely efficient string excitation. By narrowing or broadening the central projection, the field strength in the air gap and the extent of the field in the direction of the string can be changed. If, for example, vibrations with small wavelengths are to be excited, then it must be ensured that the extent of the magnetic field in the direction of the string is essentially no greater than half the wavelength of the shortest wavelength sound which is still to be excitable. If this desired magnetic field expansion is smaller than the diameter of the magnets to be used, the magnetic field emanating from the permanent magnets can be narrowed to the desired extent by narrowing the core part at the middle projection. Because E-shaped Kembleche are commercially available and high-quality permanent magnets, such as samarium-cobalt (SmCo) or Neodymium-iron-boron (NdFeB) magnets, are low, the advantageous excitation devices can be produced cheaply. It goes without saying that instead of the assembled E-shaped cores also two C-shaped cores can be put together, wherein two mutually associated projections are interconnected via a permanent magnet and the other two associated projections are each provided with a coil. Optionally, cores with more than three, for example, with 13 or 14 projections, put together, at least between two associated projections, a permanent magnet is inserted, between the other pairs of projections each air gap is arranged with a string and on the projections of these projection pairs respectively Antisense wound coils are arranged. As a result, the permanent magnetic field for all air gaps originates from at least one common magnet, with the magnetic field being supplied to the air gaps through the core parts. It goes without saying that the at least one common magnet can also be designed as an electromagnet. Arrangements with 13 or 14 pairs of protrusions can be used with chromatically tuned strings of 12 single or multiple strings if the clearances between the strings are too small to insert the connecting portion of a core member or a permanent magnet therein. Optionally, such arrangements are also advantageously used on known instruments with metal strings, such as a piano.

To be able to excite the individual strings quickly and strongly in an instrument with multiple strings, preferably each string, but optionally also two or more equal tuned strings, an excitation device with two coils, at least one permanent magnet and two on the at least one permanent magnet with each other associated core parts. It goes without saying that the permanent magnetic field, whose field lines are mainly guided by the core parts, also by a current-carrying coil, which is arranged around at least one of the core parts, can be generated. If, due to the electrically generated permanent magnetic field, no permanent magnet is inserted between the core parts, a core part may be sufficient. Model calculations and tests have shown that the string is sensitive to frequency changes. Even with small deviations of the excitation frequency from the oscillation frequency of the string, the coupling deteriorates greatly. As a result, harmonics that are close to one another can be specifically, or individually, stimulated.

Even with continuous operation of the instrument with a large amplitude of the string vibration, the temperature on the outside of the coils does not rise above 50 ° C. This good thermal property results from the fact that sufficiently large excitation forces are achieved even with a small power supplied. Due to the core parts, the system also has good thermal conductors, which dissipate the heat generated by the coils to the outside.

By using closed arrangements with core parts and high-quality permanent magnets used, the efficiency compared to solutions with ferrite magnets in the coils can be increased by a factor of 10 to 15. The highest possible efficiency allows the strings to be put into extremely strong vibrations with a reasonable expenditure of energy. This is necessary if the sound of the string vibration is to be radiated acoustically, and in particular if the inventive instrument is to provide, for example, the sound of a plucked bass string. A high efficiency allows a good coupling of the string vibration to the excitation signal. As a result, both the frequency and the amplitude curve can be controlled.

The excitation device not only enables the initial excitation of the string vibration, but also the control of the course of the vibration, in particular also a damping of the string vibration. To achieve selective damping, the effective oscillation is preferably detected, an antiphase excitation signal is provided and the string is excited thereby. The detection of the effective oscillation can take place via a separate pickup, via an optical deflection detection in the case of the excitation device used for damping or via a signal detected by the excitation device. If vibrations with different frequencies are also to be attenuated differently, then the amplitude measurement must be carried out frequency-dependent.

It goes without saying that instead of the active damping by an excitation device, also a mechanical damping can be provided. The mechanical damping takes place with the help of damper elements, which can be brought to the string. Preferably, a mechanical damping for each string comprises two damper elements which are each movable from opposite sides against the string. The drive of the dampers, for example, an electromechanical system with which both each string individually and all the strings can be damped together. The electromechanical system comprises electric motors and / or electromagnetic lifting devices, in particular positionable lifting magnets.

Each excitation device is operated via the interface, wherein the interface via at least one input, a signal from the outside can be fed. The interface is preferably designed so that substantially any electrical or electronic signals, analog, digital or even in MIDI format, in particular signals from synthesizers, keyboards, computers and signals from microphones or speaker outputs can be fed. To provide MIDI signals, devices such as master keyboards, MIDI sax, MIDI guitar or other MIDI controllers are available for a variety of instrumental techniques. In order to enable a versatile implementation of various electrical signals, the interface preferably comprises, in addition to at least one MIDI input, several parallel sound inputs, which can be switched in particular from analog to digital and vice versa. In order to be able to use signals originating from a microphone to control the instrument according to the invention, at least one microphone input is provided. For example, the sound of a violin can be used to control a microphone input. If there is a signal for driving the individual strings for an instrument with a chromatic set of strings, then it is expedient to use an interface with a chromatic input. Because strings with long oscillation durations also require attenuation of the strings for good sound quality Interface preferably a damping input or pedal input, which is connected for example with at least one damping pedal. About the damping input, the damping behavior of the mechanical damper and optionally the non-contact damping is influenced by means of the excitation devices, for example by the attenuation is omitted or weakened when the pedal is pressed.

The interface generates control signals for the excitation devices, or for amplifiers of the excitation devices, based on the input signals. In the simplest case, an input signal is forwarded directly to the excitation devices, so that the interface is to be regarded merely as a signal input. If the signals used to control the instrument via microphone or sound inputs are not aligned with the instrument's characteristics, the sound quality can be optimized through the use of filters and two different modes of excitation. A The first mode of excitation, called excitation mode, uses a common excitation signal for the simultaneous activation of all excitation devices, the strings responding only to the signal components having the natural frequencies of the respective string in accordance with their natural frequencies or overtone spectra. A second mode of excitation, called audio division mode, assigns the tones of the signal to the strings on which these tones sound. Accordingly, signal components are respectively supplied to corresponding excitation devices, or their amplifiers.

The amplifier of an excitation device should have a high efficiency, so that the largest possible share of power in the excitation of the string and a small power component passes into heat. In order to dissipate the heat generated by the power loss, a cooling is usually required, resulting in large dimensions of the amplifier. In order to improve the active power, preferably a class D amplifier should be provided. Class D amplifiers are based on the principle of pulse width modulation and are available in B. Sliders, Class D IC Amps: Ready for audio prime time, EDN Magazine 1.7.1999 described. The input signal either switches the output on or off. The height of the output signal is controlled by the pulse width. The reason for the high achievable efficiency lies in the binary operation of the circuit: the losses are mainly generated by the circuit breaker. In contrast, with AB amplifiers, the power loss is already caused, among other things, by the adjustment of the operating point. The achievable efficiency of Class D amplifiers is in the range 80 to 90%. For audio applications, special output filters are needed to use such amplifiers to minimize harmonic distortion. Since the excitation device itself already has a rather large inductance, this is not necessary in the present instrument.

For an amplifier to be designed to drive the excitation device, the required frequency response must be known. For this reason, the frequency response of the system of excitation device and string should be determined. Because the power requirements of an amplifier to excite a bass string are particularly high, the excitation of a bass string was carefully analyzed. The measured relative sound pressure shows that above a frequency of about 6kHz no swinging of the bass strings is detected. Also, by increasing the power input, the bass string can no longer be stimulated. From a frequency of about 5kHz, the vibration of the bass string superimposed by a singing of the encoder coils. At higher frequencies, the distance between the resonances is no longer exactly λ / 2, which can be explained by the physical properties of the bass string, in particular the fact that the nodes are not infinitely small. The low-pass character of the system is clearly visible in the frequency response. This can be explained by the inductive load of the excitation device. If the string to be stimulated is not sufficiently taut, a poor transmission of the string vibration to the sounding body is observed especially at low frequencies. In order to achieve good efficiency with the non-contact excitation device in the lower frequency range, the strings must be sufficiently well stretched.

In order to convert high-frequency signal components into a sufficiently strong sound, the amplifier is preferably preceded by an equalizer, which raises the high frequencies. The limitation of the frequency response is caused by the inertia of the string. In addition, at high frequencies half the wavelength is in the range or below the extent of the excitation device or encoder length. For a 6kHz swinging test string λ / 2 = 12.5mm. With a donor length of 10mm, the limit of meaningful excitation of the string is reached. So if no tones above 6kHz can be generated, the amplifier has to have a linear behavior only below 6kHz. Such class D and pulse width modulation amplifiers are commercially available. Therefore, a non-contact excitation device with high efficiency can achieve string vibrations covering sufficiently large frequency and volume ranges.

Until now, the composing and improvisation techniques used by the computer were limited to the electronically generated sound emitted by the loudspeaker. Due to the instrument according to the invention, these compositions come about the natural string sound and its radiation through the wooden body made of wood to a novel, outstanding sound effect.

In order to protect the instrument and / or to influence the sound emission, an envelope is preferably provided. The sheath is connected to the holding device and comprises at least one flat, preferably curved, directional element, which can be used to limit the spatial area in which the sound of the sound body is emitted is. Thus, the shell can also take a protective function, this includes on the side facing away from the strings back of the orchestra a floor area and then a leading around the orchestra wall area. The at least one directional element can preferably be applied as a cover to the wall region, so that the shell completely encloses the sounding body. In a particularly preferred embodiment, lamellar directional elements are guided on a guide device. The directional elements can, for example, be aligned substantially in the direction of a dominant emission direction. Optionally, the directional elements can form deflection surfaces, which extend for example in a horizontally oriented sound body at an angle of substantially 45 ° to the horizontal above the orchestra and deflect the dominant vertical upward sound of the sound body in a substantially horizontal direction.

In instruments with metal strings that are sufficiently strong, an excitation device for non-contact excitation of at least one string can be advantageously used. This means that at least one string of the known instrument can be controlled by the installation of the excitation device via an interface with a supplied electrical or electronic signal. In this case, the string to be excited must comprise magnetizable material. The insertable excitation device comprises two, on both sides of an air gap for receiving the string, arranged substantially around a common coil axis coils and a magnetic device for generating a permanent magnetic field, preferably at least one permanent magnet. The permanent magnetic field in the region of the air gap is substantially parallel to the coil axis and the coils are wound and connected so that they generate magnetic fields with oppositely directed same poles in the current-carrying state, so that an inhomogeneous magnetic field can be achieved in the air gap, the string with a Deflection force can be acted upon makes.

In particular, it would also be possible to build an electric instrument with a chromatic string set and non-contact excitation devices, where the sound would be emitted via pickups, amplifiers and speakers. Although the sound quality would be degraded, the excitation possibilities emanating from the excitation device and, in particular, also the described damping possibilities could be advantageously used for the generation of the sound.

• Fig. 1 eine perspektivische Ansicht eines Saiteninstrumentes mit einer berührungslosen Anregungsvorrichtung,
• Fig. 2 eine perspektivische Darstellung des Klangkörpers,
• Fig. 2a, 2b Schnitte gemäss A bzw. B in Fig. 2
• Fig. 2c ein Detail aus Fig. 2a
• Fig. 3, 4 eine schematische Darstellungen von Anregungsvorrichtungen
• Fig. 5a eine schematische Darstellung der auftretenden Kräfte
• Fig. 5b eine funktionale Darstellung der Kraftwirkung als Funktion der Auslenkung bei verschiedenen Magnetfeldstärken
• Fig. 6 eine funktionale Darstellung der Anregungswirkung in Funktion der Lage der Anregungsvorrichtung
• Fig. 7a, 7b, 7c schematische Darstellungen der mechanischen Dämpfung
• Fig. 8 eine schematische Darstellung der berührungslosen Dämpfung
• Fig. 9 eine schematische Darstellung des Interface
• Fig. 10 eine perspektivische Darstellung der Anwendungsmöglichkeiten des Instrumentes
• Fig. 11, 12, 13, 14 schematische Darstellungen von berührungslosen Anregungsvorrichtungen
• Fig. 15a eine Seitenansicht eines Instrumentes
• Fig. 15b, 15c, 15d schematische Frontansichten des Instrumentes und
• Fig. 16a-d schematische Darstellungen der Instrumentenhülle

The invention will be further described in the figures by way of examples. It shows

• Fig. 1 a perspective view of a stringed instrument with a non-contact excitation device,
• Fig. 2 a perspective view of the orchestra,
• Fig. 2a, 2b Sections according to A or B in Fig. 2
• Fig. 2c a detail from Fig. 2a
• Fig. 3, 4 a schematic representations of excitation devices
• Fig. 5a a schematic representation of the forces occurring
• Fig. 5b a functional representation of the force as a function of the deflection at different magnetic field strengths
• Fig. 6 a functional representation of the excitation effect in function of the position of the excitation device
• Fig. 7a, 7b, 7c schematic representations of the mechanical damping
• Fig. 8 a schematic representation of the contactless damping
• Fig. 9 a schematic representation of the interface
• Fig. 10 a perspective view of the applications of the instrument
• Fig. 11, 12, 13th . 14 schematic representations of non-contact excitation devices
• Fig. 15a a side view of an instrument
• Fig. 15b, 15c, 15d schematic front views of the instrument and
• Fig. 16a-d schematic representations of the instrument shell

Fig. 1 shows an inventive instrument 101 with 12 chromatically tuned strings 102, which are held by an adhesive device 103 tensioned. In a preferred embodiment, each tone is assigned at least two strings directly adjacent to one another, or a multiple string of strings. In order to bring the individual strings or the multiple string strands into vibration, each string 102 or each multiple string of strings is associated with an electrically or electronically operated excitation device. For holding the excitation devices, at least one carrier 104 with passage openings 104a for the strings 102 is provided. Optionally, two carriers 104 with excitation devices are arranged at different positions along the strings 102. Because the natural vibrations in the areas of their nodes are not excitable, are at the different Positions different natural vibrations of the strings 102 different excitable good. In addition, the excitation devices of the one carrier 104 can be configured such that they act with greater excitation on the strings 102 than the excitation devices of the other carrier 104, and thus are more suitable for exciting oscillations with longer wavelengths.

The holding device 103 comprises two side parts 105 and at least one, preferably two, but especially three or more support columns 106 connected to both side parts 105. The strings 102 are arranged between the two side parts 105, with a tensioning device being attached to one side part 105 for the tensionable fastening is provided. The one side part 105 comprises a scale plate 107, so that the string length gradually increases from a shortest to a longest string. In order to accommodate the high clamping force of all strings, 105 inwardly projecting ribs 105 a are formed on the side members, which are connected to the support columns 106. In order to prevent the formation of unwanted noise, the ribs 105a are preferably formed as double ribs with a hard rubber intermediate layer and the support columns 106 are at least partially filled with hard rubber. The carriers 104 with the excitation devices are attached to the support columns 106 and can be slightly adjusted so that the strings 102 are guided substantially centered through the passage openings 104a.

For acoustic emission of the string vibrations a sound body 108 is provided. The sound body 108 is formed as a hollow body and comprises a membrane 109, annularly closed frames arranged 110 and in particular a bottom 111. At one end side of the frames 110, the membrane 109 and the other end face of the bottom 111 is arranged. The membrane 109 faces the strings 102, the strings 102 abutting against a web 112, which in turn is in contact with the membrane 109. The sound body 108 is attached via a distance adjusting device, not shown, with damping rubber elements on the holding device 103, in particular on the support columns 106. By means of the distance adjusting device, the voltage with which the strings 102 rest on the web 112 can be set optimally.

For supplying signals to the excitation devices in the carriers 104, at least one interface 113 is provided to which control signals can be supplied via at least one input 113a. From the interface, cables 113b lead to the excitation devices.

In order to ensure a high sound quality of the instrument 101, a new, simply constructed sound body 108 with a prestressed membrane 109 has been developed. According to Fig. 2, 2a, 2b and 2c four frames 110 are assembled into a rectangle and connected to the bottom 111 at one end face. The long side frames 110 are slightly outward against the membrane 109. In order to increase the stability of the long frames 110 in the membrane 109, in the frame 110 at the membrane 109 inwardly, substantially parallel to the membrane 109 extending, but somewhat spaced from this longitudinal ribs 114 are attached. In order for the diaphragm 109 to have particularly good vibration characteristics, it is made of tonewood with tight annual rings and connected in a prestressed state to the sides. In the tonewood, the tree rings are perpendicular to the surface, the fiber direction preferably extends in the direction of the large Recheckseite and in the direction of the small Recheckseite follows year ring on tree ring. The membrane 109 is bent at least perpendicular to the fiber direction, but preferably also along the fiber direction slightly and thus biased to the frame 110 fixed, in particular glued. The frames 110 are on the front side, which faces the diaphragm 109, curved, wherein the end faces of the shorter frames are more curved than the end faces of the longer frames. The preferred radii of curvature depend on the quality of the wood and for the short side are below 1.2 m, in particular below 1 m, preferably at substantially 0.95 m. For the long side, the preferred radii of curvature are above 10 m, in particular above 12 m, preferably at substantially 14 m. The membrane 109 thereby obtains the shape of a partial surface of a torus or a barrel body, said toroidal surface preferably projecting against the string and therefore radiates in a larger solid angle than a curved against the interior of the sound body surface. The longitudinal ribs 114 prevent the tension of the diaphragm 109 from causing deformation of the long frames 110.

In order not to negatively change the stress distribution in the membrane 109 through an opening, according to a preferred solution, the at least one opening 115 for the air exchange and the emission of sound from the interior of the sound body 108 in the central region of the long frames 110 is formed. The opening 115 extends in a slot shape through the frames 110 and the longitudinal ribs 114. In order to also in the region of the openings 115 to hold the membrane 109, on the longitudinal ribs 114 a protruding to the membrane 109 holding portion 114a is formed.

Fig. 3 shows an annealing device 116, with an oscillating force F perpendicular to the longitudinal direction of the string 117 can be exerted on a string 117 with magnetizable material. On both sides of the string 117 coils 118 and 118 permanent magnets 119 are arranged in the coils. The two permanent magnets are aligned in the same direction and generate in a Luftspaft 120 with the string 117 a strong magnetic field. In order to set the string in oscillation in this permanent magnetic field, inhomogeneities in the magnetic field are generated by the coils 118 in accordance with an excitation signal. The coils 118 are wound in opposite directions and connected so that magnetic fields, which are each directed with the same poles against each other, arise. In one or the other current direction, the total, given by the coils and the permanent field, magnetic field density is increased against one or the other coil in accordance with the current direction alternating inhomogeneous magnetic fields in the air gap act with appropriate forces on the magnetizable material of the string 117th ,

$$F_2=\frac{A_L}{2{\mu }_0}{\left(B_{d2}-B_E\right)}^2$$

• wobei B_d1, B_d2 von den Permanentmagneten erzeugte Flussdichten bei den Flächen A1 bzw. A2,
• B_E von einem Elektromagneten erzeugte Flussdichte bei A1 bzw. A2,
• A_L eine Fläche und
• µ₀ eine magnetische Feldkonstante darstellt

Fig. 4 shows a preferred excitation device 116 ', are used in the magnetizable core parts 121, in particular made of electrical steel iron cores. These core parts 121 are E-shaped, wherein the outer two projections 121 a are each connected to each other via a permanent magnet 119 and about the central projection 121 b each have a coil 118 is disposed. The coils 118 are as shown Fig. 3 wound in opposite directions or connected. By narrowing or broadening the middle projection 121b, the field strength in the air gap 120 and the extent of the field in the direction of the string 117 can be changed. By the core parts 121, the proportion of air in which form the magnetic field lines and thus the resistance to the magnetic field can be reduced. As a result, the field density in the region of the air gap 120 can be increased. The superimposition of the fields of the permanent and electromagnets 119, 118 leads in the air gap 120 to the marked inhomogeneous magnetic field. The force effect of the inhomogeneous field on the string 117 can be determined from the Maxwell stress by integration over a string-enclosing system boundary G. According to Fig. 5a For estimating the forces in the direction of the common axis of the coils 118, the system boundary G is divided into four partial surfaces A1, A2, A3 and A4 and it is assumed that the magnetic field perpendicular to the surfaces A1 and A2 is equal to the one in FIG Substantial constant value B1 or B2 is perpendicular to the surfaces A3 and A4, the magnetic field is vanishingly small. In a first approximation, the forces F1 and F2 acting on the partial surfaces A1 and A2 can be calculated as follows: $${\mathrm{<figure-callout\; id="1"\; label="F"\; filenames="imgf0003.png,imgf0004.png"\; state="\{\{state\}\}">F</figure-callout>}}_1=\frac{A_{\mathrm{<figure-callout\; id="2"\; label="L"\; filenames="imgf0003.png"\; state="\{\{state\}\}">L</figure-callout>}}}{2{\mathrm{<figure-callout\; id="0"\; label="\mu "\; filenames="imgf0003.png,imgf0004.png"\; state="\{\{state\}\}">\mu </figure-callout>}}_0}{\left(B_{d1}+B_e\right)}^2$$

$${\mathrm{<figure-callout\; id="2"\; label="F"\; filenames="imgf0003.png"\; state="\{\{state\}\}">F</figure-callout>}}_2=\frac{A_{\mathrm{<figure-callout\; id="2"\; label="L"\; filenames="imgf0003.png"\; state="\{\{state\}\}">L</figure-callout>}}}{2{\mathrm{<figure-callout\; id="0"\; label="\mu "\; filenames="imgf0003.png,imgf0004.png"\; state="\{\{state\}\}">\mu </figure-callout>}}_0}{\left(B_{d2}-{\mathrm{<figure-callout\; id="2"\; label="B\; e"\; filenames="imgf0003.png"\; state="\{\{state\}\}">B\; </figure-callout>}}_e\right)}^2$$

• wherein B _d1 , B _d2 generated by the permanent magnets flux densities at the surfaces A1 and A2,
• B _E flux density at A1 and A2, respectively, generated by an electromagnet,
• A _L an area and
• μ _{0 represents} a magnetic field constant

The resulting force is calculated for B _d1 = B _d2 = B _{d as} follows: $$\mathrm{F}\mathrm{=}{\mathrm{F}}_{\mathrm{1}}\mathrm{-}{\mathrm{<figure-callout\; id="2"\; label="F"\; filenames="imgf0003.png"\; state="\{\{state\}\}">F</figure-callout>}}_{\mathrm{2}}\mathrm{=}\mathrm{k}\left({\mathrm{B}}_{\mathrm{d}}{\mathrm{B}}_{\mathrm{e}}\right)$$

The excitation force thus increases both with the field strength of the permanent magnets and with the field strength of the electromagnets. Because B _E originates in F ₁ from one and F ₂ from the other electromagnet 118, an arrangement with only one coil would make a much smaller force achievable.

Fig. 5b shows the force on the string 117 as a function of its deflection in the direction of the axis of the electromagnet 118 for three different types of permanent magnet 119, which generate magnetic fields of 0.25, 0.5 and 1T in the air gap. In the center of the air gap, or at the deflection 0, the force is substantially proportional to the magnetic field of the permanent magnet.

Fig. 6 shows that the positioning of the excitation device 116, 116 'and the carrier 104 along the string plays 102.117 a crucial role. Especially for the excitation of the low-frequency vibrations, it is important to have enough distance from the next node, because with increasing distance from one Node, the available lever is larger, so that with the same force effect, a greater deflection is achieved. For the excitation capability shown in the y-direction as a function of the relative position of the excitation device along the free-swinging string, ie between the one side part 105 and the web 112, the lowest four partial vibrations were taken into account. The excitation capability is at a position x / l = 0.83 absolute maximum. This means that optimal excitation of the lowest four sub-frequencies is possible at this point. If higher natural frequencies of the string are included in the calculation, the maximum shifts to a position x / l = 0.87. The strings can thus be stimulated optimally in the vicinity of the bridge or in the vicinity of the opposite side part.

Because the strings 102 linger long due to the high clamping forces, they must be able to be damped. Fig. 7a and 7b show schematically two solutions for the mechanical damping of a string 102. The mechanical damping is carried out by means of dampers 122, which are brought from two sides to the string. According to Fig. 7a For example, the dampers 122 are moved toward and away from the string 102 about a pivot 123 on each side of that pivot point. According to Fig. 7b The dampers are moved against each other, the string can be clamped between the dampers.

The drive for the movement of the dampers is an electromechanical system, with which each string individually as well as all strings can be damped together. The type of damping, in particular the minimum distance of the dampers 122 from the string 102, is set, for example, by means of a pedal or another control device. According to Fig. 7c, each damper can take a position, or perform a position movement, in the range between the maximum damping pressure on the string + and the complete release of the string -. The effective position and / or a stroke performed during damping can be adjusted by the pedal. It is possible to flexibly exceed the zero point given by the pedal, in particular up to the maximum damping pressure. As a result, strongly vibrating strings can be ideally dampened even with a weak damping due to the pedal position.

The mechanical dampers each include a shock absorber sole with a damper shoe and an adjustment device for aligning the damper shoe along and across the string. The actuation of the damper via mechanical lifting devices with electric motors or electromagnets. In order to achieve a reproducible damping, the drive systems must have a position control. The zero point setting is made either by a synchronous positioning of the magnet systems or centrally by a separate drive system.

Fig. 8 shows a damping solution in which the vibration of the strings 102 is detected individually and in accordance with the detected string vibration with an excitation device 116 ', the strings 102 are excited in antiphase. For this purpose, the movement of the string 102 is detected via a position measuring device 124, for example an optical distance measurement, but optionally via a measurement on the excitation device, for example an induction measurement. From the position measurement, a speed signal can be derived, which can be used to generate a damping force. The position or movement of the string is measured as close as possible to the excitation or damping device.

To control the non-contact damping preferably a control loop is used, the upper specifies a desired function the amplitude curve of the string vibration during the damping process. With an amplitude measurement of the decay process can be monitored and possibly influenced by deviations. The amplitude measurement must be insensitive to lateral vibrations, so that unwanted movements can not be excited by the damping. If the amplitude measurement frequency-selective, so the attenuation frequency-selectively carried out. The non-contact attenuation enables targeted clearing of signal spectra in one signal. This functionality is not possible with a mechanical damper. For optimum cushioning, the transmitted force should be applied in an antinode.

Fig. 9 shows an embodiment of an interface 113 with different inputs. In addition to at least one MIDI input 125, there are several parallel sound inputs 126, which can be switched in particular from analog 126a to digital 126b and vice versa. Preferably, at least one microphone input 127 is provided. For example, the sound of a violin can be used to control a microphone input. If a chromatic signal for driving the individual strings is now available for an instrument with a chromatic string set, it is expedient to use an interface with a chromatic input 128, which results in an ideal assignment of the tones and in particular no clumping of the tone. Because strings 102 with long periods of vibration also require attenuation of the strings for good sound quality, the interface 113 includes, in particular, an attenuation input 129 connected, for example, to at least one attenuation pedal. Above the damping input, the damping behavior of the mechanical Damper and / or the damping influenced by the excitation devices, for example by the damping is omitted or weakened when the pedal is pressed.

The interface generates control signals for the excitation devices 116, 116 ', or for amplifiers 130 of the excitation devices, based on the input signals. In an instrument with 12 strings, 12 excitation devices 116 'and 12 amplifiers 130 are used. The amplifiers 130 may be considered as part of the excitation devices 116 'or as part of the interface 113. The signals which enter the interface 113 via a MIDI input 125 may comprise a great variety of information, the interface 113 comprising different elements for implementing this information. To provide control signals for the mechanical damping 131, a first damping control 132 is provided, to which signals from the damping input 129 and from the MIDI input 125 can be fed. To control the non-contact damping, a second damping control 133 is provided which processes signals from the position measuring device 124, the damping input 129 and the MIDI input 125 and makes the control signals supplyable to the amplifiers 130.

Because the signals applied to upper microphone or sound inputs 127, 126 to control the instrument are not aligned with the characteristics of the instrument, the sound quality may become two different through the use of first and second filters 134, 135, respectively Enable suggestions. A first mode of excitation, called excitation mode, uses a common excitation signal of the first filter 134 to simultaneously drive all the amplifiers 130, the strings 102 responding only to the signal components having the eigenfrequencies of the respective string 102 in accordance with their eigenfrequencies or overtone spectra. A second, Tonaufteilungsmodus called, way of stimulating assigns the sounds of a signal to the strings 102 on which sound these sounds. Correspondingly, signal components starting from the second filter 135 are supplied to respective amplifiers 130 via a sound splitting element 136. If the original signal originates from the microphone input, it is changed before the second filter 135, preferably processed by an audio analysis element 137, in particular signals for the attenuation controls .132, 133 are derived from the signal and can be supplied to it. Connections are also provided. which allow to influence the filters 134, 135 and the audio divider 136 via the MIDI input or to control. The signals of the chromatic input 128 are supplied substantially directly to the respective amplifiers 130.

Fig. 10 shows the versatility of the instrument according to the invention 101, which can be used in a raised position or optionally in a horizontal position. The instrument stands on feet 146. In order to protect the instrument 101 and / or to influence the Marigab radiation, a sheath 138 is preferably provided. The case. 138 is connected to the holding device 106 and comprises at least three, flat, preferably curved lamellar, directional elements 139, which is used to limit the space in which the sound of the sound body 109 is radiated. Thus, the shell 138 can also take a protective function, this includes on the side facing away from the strings back of the orchestra a bottom portion 140 and then a leading around the orchestra wall 141: The directional elements 139 can be applied as a lid to the wall portion 141, so that the Case 138 surrounds the sound body 109 completely. The directional elements 139 are guided on a guide device, not shown, with hinges for the radial movement and with parallelograms for the proportional longitudinal adjustment. The directional elements may, for example, form deflecting surfaces, which run, for example, in a horizontally oriented sounding body at an angle of substantially 45 ° to the horizontal above the sounding body and deflect the sound of the sounding body which emerges vertically upwards in a substantially horizontal direction.

To play the instrument, or to provide control signals for the instrument, devices such as a keyboard 142, a microphone 143, a synthesizer with keyboard 144 or any audio terminal 145 can be used with a signal output, such as a speaker output. The instrument can be played like a keyboard instrument. But it can also be the microphone recording a conventional instrument used for driving. When the instrument receives the signals of an audio terminal or a sequencer, it can be used as an automatic house instrument.

With the string instrument according to the invention, strings can be caused to vibrate by various contactless excitation devices. Fig. 11 , shows an electromagnetic excitation device with two hard magnets 11 and 12, a few millimeters spaced apart from each other and surrounded by a respective electromagnet 13 and 14. Due to the distance between the magnets 11 and 12, a single or multiple strings of strings is performed 15. The two hard magnets 11, 12 must be arranged so that the north pole points to the south pole. The winding sense of the electromagnets 13, 14, however, must run against each other (eg north to north pole).

Fig. 12 shows an excitation device with two soft magnets 21 and 22, which are arranged in some Mittimetem distance from each other and surrounded by a respective electromagnet 23 and 24. The two electromagnets 23, 24 should get through an armature 25 magnetic final. Due to the distance between the magnets 21, 22, a single or multiple strings 26 is performed The string 26 is traversed by a constant current. The current should be selected so that there are no thermal effects in the string. The current causes a magnetic field around the string 26. The magnetic fields of the electromagnets 23, 24 and the magnetic field of the string lead to a force on the string 26, which results in a vibration

Fig. 13 describes an excitation device, which achieves the force effect by a modulated electrostatic field or by means of a plate which is arranged longitudinally to the string. On the string or the plate is additionally on a modulating voltage.

Fig. 14 shows an excitation device with a dual plate arrangement, which achieves the force effect by a modulated electrostatic field by means of two plates (+ U = / + 1000V and -U = / -1000V), which are arranged parallel and longitudinal to the string. The modulating voltage is additionally applied to the string.

The geometric dimension of the magnets 11, 12, 21 and 22 according to 11 and FIG. 12 , or the plates according to Fig. 13 and 14 , in the longitudinal direction of the string should be as small as possible in relation to the string length. The shortest wavelength on the string (cutoff frequency) that can be excited corresponds to this dimension of the magnet or plates. In a solution according to Fig. 11 This geometrical measure may only be so small that the magnetization of the electromagnet does not exceed the remanence of the hard magnet.

In the excitation devices according to the Fig. 11 to 14 can by a two-way system consisting of a low-frequency excitation device (with increased geometric dimension for String length) and a mid-tone excitation device (with a smaller geometric dimension to the string length) an increased power flow can be achieved. In the arrangement of this two-way system, the positions of the two excitation devices on the string length must be selected specifically so that as few as possible points of accounts of partials of the string are superimposed, or no phase changes from the low-frequency Anreungsvor direction to mid-tone excitation device and vice versa take place.

The string instrument according to the invention regulates the supply of digital or electro-synthetically generated sounds to the strings via two channels: a) the sounds are assigned to the strings individually according to frequency / pitch, and b) each tone can be globally adjusted throughout the octave (12 string strings), be injected (volume). This extends the overtone spectrum beyond one string. Many tones also contain irregular overtones, which thus form on neighboring strings.

The stringed instrument according to the invention, in order to be able to dampen the vibrating strings, feeds the strings removed from the strings via a pickup (for example opto-couplers) in phase to the strings via the contactless excitation apparatuses.

According to Fig. 15a the interface and the amplifier 59 of the stringed instrument according to the invention have their place in the back behind the kangaroo body.

The string instrument according to the invention uses one or more strings of strings for each of the 12 chromatic tones and a tone generator system or an excitation device. This makes it possible to make music in all 12 keys; on the 2nd part of a string of strings, the first octave can be formed, or on the 4th part of the double octave, etc.

The inventive stringed instrument may consist of a single instrument or of several register instruments. A single instrument requires a stringing of two chromatic octaves (alto-octave, eg g-fis and bass-octave, contra G to FIS) to reach the standard pitch (plus the 2nd, 4th, etc. partials). A register instrument must be equipped with a chromatic octave string (12 string strings). Two register instruments (alto and bass) reach the standard Pitch also plus the 2nd, 4th, etc. partials. A quartet of four, or a quintet of five register instruments (soprano, alto, tenor, bass and contra-bass) can be played by virtue of tonal splitting honored by basic notes.

The construction of the register instrument according to the invention ( Fig. 15a ) separates the tonal, the static and the protective parts. Above the sound corpus 51; which is held by transition parts 52 in the outer construction, the strings 53 are stretched over the web 54 The string of strings is held by an enveloping frame, which comprises two side parts 55, which are supported by the central support column 57 and acted upon by two counter-trains 56 with a counter force , The shell 58 is used both as a protection, as well as a horn or use can be separated from the actual instrument (sound corpus with enveloping frame).

The construction of the inventive register instrument allows playing in a horizontal (lying like a grand piano) as well as in a vertical position (standing like a Kirchenorgelregister). The instrument can be rotated in both positions on the main axis ( Fig. 15c, 15d ). This is very useful in the horizontal position, so that the angle of radiation to the player or the audience is selectable.

The inventive protective sheath ( Fig. 16a ; horizontal section of the standing instrument) consists of a back element R and two movable wings F1 and F2. The two wings are provided with hinges behind Sh and in the middle Sm and thus movable. By a number of slats that can be pushed over each other, the wings F1, F2 can be shortened or extended ( Fig. 16c ). These. Slats can also be unscrewed and opened, so that the sound radiation through the protective cover is possible ( Fig. 16b ).

• Instrument stehend: geschlossener Zustand (Fig. 16a; horizontaler Schnitt).
• Instrument stehend: Lamellen ausgedreht, geöffnet (Fig. 16b; horizontaler Schnitt). Instrument stehend: beide Flügel sind als Schallrichter zum Konzertsaal hin geöffnet (Fig. 16c; horizontaler Schnitt).

The two wings F1 and F2 of the inventive register instrument can be arranged and converted as follows:

• Instrument standing: closed condition ( Fig. 16a ; horizontal section).
• Instrument standing: slats turned off, opened ( Fig. 16b ; horizontal section). Instrument standing: both wings are open as a sound judge to the concert hall ( Fig. 16c ; horizontal section).

Instrument lying: the first wing F1 is divided into parts H and V and mounted laterally (as frames) and the second whole wing F2 is used as cover and horn H and V, the middle hinge is locked ( Fig. 16d ).

Claims (15)

1. Instrument with at least one tunable string (102), a holding device (103) for holding the at least one string (102), at least one electrically or electronically operated exciting device (116, 116') for contact-lessly exciting of said at least one string (102), a sounding body (108) for acoustically radiating oscillations of the string and an interface (113) for supplying a signal for controlling the at least one exciting device (116, 116') characterized in that a bridge (112) renders transferable the oscillations of the string to the sounding body (108), the at least one string (102) comprises a magnetizable, particularly ferromagnetic, material, the at least one exciting device (116, 116') comprises two coils (118) situated at both sides of an air gap (120) including said string (102, 117) and substantially wound around a common coil axis, and a magnetic device for generating a permanent magnetic field, wherein the permanent magnetic field in the region of said air gap (120) extends substantially parallel to said coil axis, and said coils (118) being wound and connected in such a manner that they generate magnetic fields of equal poles opposite to each other when traversed by a current, so that a non-homogeneous magnetic field can be generated in said air gap (120) which enables said string to be biased by a deflection force.
2. Instrument according to claim 1, characterized in that said holding device (103) comprises two lateral parts (105) and at least one supporting column (106) connected to said two lateral parts (105), the at least one string (102) being attached to both lateral parts (105), or parts connected with them, and being tensionable for tuning purposes.
3. Instrument according to claim 1 or 2, characterized in that said body (108) is arranged between said strings (102) and said at least one supporting column (106), and that preferably a spacing adjustment device is inserted between said body (108) and said holding device (103), particularly said at least one supporting column (106), which enables said body (108) together with said bridge (112) to be pressed against said at least one string (102).
4. Instrument according to any of claims 1 to 3, characterized in that said body (108) comprises a membrane (109), a casement (110) closed in the shape of a ring and, in particular, a bottom (111), wherein on one of the front surface of the casement (110) the membrane (109) is attached, while on the other front surface said bottom (111) is arranged, and the membrane (109) is facing said at least one string (102) and is preferably formed of sounding timber and is particularly connected to the casement (110) in a pre-stressed condition by bending into the shape of a torus or of a ton body.
5. Instrument according to any of claims 1 to 4, characterized in that at least one opening (115) is formed in said body (108) by which an air exchange is enabled from the interior of the body (108) to ambient, said at least one opening (115) being preferably formed within the region of at least one part of the casement (110).
6. Instrument according to any of claims 1 to 5, characterized in that a chromatically tuned set of strings is pre-stressed, wherein at least individual strings (102) are optionally present two-fold, particularly a chromatically tuned set of strings of two octaves including at least 24 strings being provided, for example of a tuning of g to f sharp' and contra G to F sharp, preferably, however, of one octave only encompassing at least 12 strings, for example of a soprano, alto, tenor, bass or contra-bass level.
7. Instrument according to any of claims 1 to 5, characterized in that the magnetic device for generating a permanent magnetic field includes at least one permanent magnet (119) of high magnetic flux density, preferably a samarium-cobalt (SmCo) magnet or neodymium-iron-boron (NdFeB) magnet.
8. Instrument according to claim 7, characterized in that at least one, preferably two, core parts (121) of magnetizable material are provided which, together with said at least one inserted permanent magnet (119), form a substantially closed magnetic field conductor with exception of said air gap (120), wherein in particular two E-shaped core parts (121) are inserted which are interconnected at the two outer projections (121 a) each through a permanent magnet (119), while around each of the center projections (121b) one of the two coils (118) is arranged.
9. Instrument according to any of claims 1 to 8, characterized in that said interface (113) comprises at least one MIDI input (125) and preferably a plurality of sound inputs (126) which are, in particular, switchable from analogue to digital and vice-versa, particularly at least one microphone input (127), optionally a chromatic input (128) and a deadening input (129), said interface comprising further signal processing elements, such as filters (135, 135), analysis elements (137) and apportion elements (136) which, starting from the input signals, enable obtaining control signals for amplifiers (130) of the exciting devices (116, 116').
10. Instrument according to any of claims 1 to 9, characterized in that a deadening device is provided, which preferably enables detecting the actual oscillations, particularly of their phase position, by means of a sensor (124) for achieving selective deadening, and enables feeding said string (102) with an exciting signal of the exciting device (116, 116') of the opposite phase and/or that a mechanical deadening device is provided which enables pressing electro-mechanically actuated damping elements (122) against said string (102), the movement of said damping elements (122) being preferably dependent on the actual string oscillation and/or controllable by a given function of motion.
11. Instrument according to any of claims 1 to 10, characterized in that said instrument may be positioned both horizontally and vertically and/or an envelope (138) is fastened to the holding device (103) which comprises a bottom portion (140) at the rear of the body (108) averted from the strings (102), and a joining wall portion (141) surrounding the body as well as a lid for engaging said wall portion (141), preferably including at least one adjustable directional element (139).
12. Exciting device for contact-lessly exciting at least one prestressed string (102) comprising magnetizable material, characterized by two coils (118) situated at both sides of an air gap (120) including said string (102, 117) and substantially wound around a common coil axis, and a magnetic device for generating a permanent magnetic field, preferably at least one permanent magnet (119), said permanent magnetic field in the region of said air gap (120) extending substantially parallel to said coil axis, and said coils (118) being wound and connected in such a manner that they generate magnetic fields of equal poles opposite to each other when traversed by a current, so that a non-homogeneous magnetic field can be generated in said air gap (120) which enables said string to be biased by a deflection force.
13. A process for generating sound by processing an external signal into a control signal for at least one amplifier (130), contact-lessly exciting a pre-stressed string (102) by an exciting device (116, 116') operated electrically or electronically by said amplifier (130), transferring the string's oscillation to a sounding body (108) via a bridge (112), and acoustical radiating the oscillations transferred to said sounding body (108) characterized in that the oscillations of the string are transferred to the sounding body (108) by a bridge (112), for contact-less exciting the string (102), the string (102) comprises a magnetizable material and two coils (118) wound in opposite direction around a common coil axis, situated at both sides of an air gap (120) including said string (102) and being simultaneously fed by said amplifier (130), said coils (118) generating alternating non-homogeneities within a permanent magnetic field in the direction of the coil axis in the region of said air gap (120) and the at least one pre-stressed string (102).
14. Process according to claim 13, characterized in that the permanent magnetic field is generated by at least one permanent magnet (119) of high magnetic flux density, preferably a samarium-cobalt (SmCo) magnet or neodymium-iron-boron (NdFeB) magnet.
15. Process according to claim 13 or 14, characterized in that a chromatically tuned set of strings comprising at least 12 strings (102) as well as an exciting device (116, 116') for each string (102) is provided, while the sound quality is optimized by using filters (134, 135) and two different methods of excitement, a first exciting method, called resonance mode, supplying a common exciting signal for simultaneously controlling all exciting devices, while a second exciting method, called tone apportion mode, supplies a special exciting signal to each exciting device in correspondence with the tuning of the string (102) thus to be excited.

Images