DE4130175A1 - Electrical string instrument such as guitar - has strings tensioned over block containing piezoelectric device used as vibration detector. - Google Patents

Abstract

The electronic guitar has a string bed with a block (6) set onto a main body. The block has evenly spaced tensioned strings (5) in contact with a top surface (9). An electromagnetic detector (13), that has a comb like profile (14), is built into the block. The spaces (11) between the projections form a field generator region and each projection is in the form of piezoelectric foils with an isolating layer inbetween. The lower end has connections to electrical output lines. ADVANTAGE - Stray electromagnetic field effects are reduced for high definition output.

Description

The invention relates to a stringed instrument, in particular a guitar, with body, top, neck, several strings and a bridge with an electric pickup, the mechanical Schwin strings by means of at least one electromechanical wall lers are convertible into electromagnetic vibrations. - The The term guitar encompasses the classical guitar as well as the American western guitar, both of which are hollow, acoustic resonance body trained body and therefore be called acoustic guitar, and on the other hand so-called called electric guitars, the body of which does not function as a resonance body niert and mostly solid with imaginative design is. Electric guitars are always equipped with an electric pickup fitted. With acoustic guitars, electric pickups are used especially used when the volume of the guitar is on should be increased electronically. Stringed instruments the one gangs mentioned have, among other things, a web, by means of which the strings face the ceiling of the body in the area of the end of the body facing away from the neck and a certain distance of the strings from the body is set up. In the As a rule, the electric pickup forms the bridge or a so-called called web insert. Basically, a web can be directly or or be supported on the ceiling via an adjusting device. With an adjustment device is, for example, an adjustment of the Distance string / ceiling or the positioning of the bridge in relation to the Feasible ceiling. An electric tonab equipped electromagnetic converter converts mechanical string vibrations directly into electrical vibr around. A string of a stringed instrument can be used with Schwin swing components in all three spatial directions. The  both in vibration perpendicular to the length of the strings components are called transverse vibrations that lead third vibration component in the direction of the longitudinal extent is called longitudinal vibration. It is understood that the Einrich device for the electrical pickup according to the rules of modern electronic electrical engineering and to the electrophysical properties of the electromechanical transducers as well as the acoustic properties of the stringed instrument is adapted. It is further understood that the sound of the electronically reproduced string instruments can by influencing the frequency spectrum of the electro magnetic vibrations with common electronic aids such as filter circles. Influencing the frequency spectrum can also be a lifelike reproduction of a aim acoustic string instrument, with the special Design of the resonance body is taken into account.

In string instruments known from practice with electrical Each string is at least an electromechanical wall assigned. The number of electrical channels of the pickup is therefore at least as large as the number of strings. The the electromagnetic vibrations taken from electrical channels must first be against electronically before playback matched their amplitude and then mixed will. This adjustment of the amplitudes is necessary because of the electroacoustic transmission factor, which is determined by the ratio the amplitudes of the electromagnetic vibrations to the acoustic Volume of a string is given, from string to string and thus from Channel to channel varies. The reason for this variation is on the one hand to see the strings that sound different in nature and on the other hand in the manufacturing tolerances of the electromechanical  Converter. Due to the large number of required electromechanical Converter and the corresponding electrical channels as well as the The necessary electronic aids for voting is Her Position of such a stringed instrument complex and expensive. In addition the acoustic sound characteristics of a so far known Stringed instruments through the constructive design of the pickup or webs negatively influenced, since they primarily with regard electromechanical properties are optimized. However, since acoustic stringed instruments the constructive design of the bridge is of considerable importance for the acoustic sound known stringed instruments in an acoustic performance without not satisfying the sound of electronic aids.

The invention has for its object a string instrument to create the basic structure described above, which a very faithful transfer without complex electronic tuning generation of acoustic vibrations into electromagnetic vibrations gene allowed, with the help of an easy to manufacture electrical the pickup, which is the acoustic sound of the string instruments practically not affected.

To achieve this object, the invention teaches that the electro has mechanical transducer tongue-shaped transducer sections, wherein a transducer section is assigned to each string that the bridge the Strings carrying vibrating bending beam sections for Transfer of the mechanical vibrations of the strings to the assigned transducer sections, each string or each wall lerabschnitt a bending beam section is assigned, and that the Bending beam sections individually with regard to their ability to vibrate are tunable. - It is understood that the electromechanical  Transducers in the area of the base of the tongue-shaped transducer sections on a part of the Web is attached. It is further understood that the ends of the tongue-shaped transducer sections on the associated bending beam sections are attached. The base side and the end side The tongue-shaped transducer sections are attached for the purpose moderately, but not restrictively, by gluing. Bend beam sections can be formed by applying a die Uniform base beam spanning the web base, the Bending beam forming sections in the areas of the strings between spaces and the ends of the cantilevers are firmly supported on the bar base is. Bending beam sections can also be formed by laying in a solid footbridge in the areas under the Strings cavities can be set up. The bending beam sections can mechanically vibrate with respect to each other be decoupled by means of incisions made on the strings facing side of the bending beam in the areas of the strings spaces are arranged. It is understood that the individual Transducer sections directly or indirectly electrically are connected.

A vibrating string forces the bending beam carrying the string section mechanical vibrations with practically the same frequencies zen on, whereby the associated tongue-shaped transducer section in Vibrations is offset and the electromechanical transducer mechanical vibrations into electromagnetic vibrations changes. This with the mechanical vibrations of the strings corresponding electromagnetic vibrations are with usual electronics processed for playback. The invention uses the knowledge that the ability of a bending beam to vibrate section apart from the material properties of the bending beam  section of its length, its cross-sectional area and its Cross-sectional shape depends. Viability means that with a certain bending vibrations vibration amplitude. The electroacoustic transmission factor for a string thus depends primarily on the geometry of the assigned bending beam section and can be varied the length, cross-sectional area and cross-sectional shape of the Bending beam section in relation to the electroacoustic over Adjust the bearing factors of other strings individually. Such individual coordination can, for example, take place according to the stipulation gene that the electroacoustic transmission factors for all strings of the stringed instrument are practically the same. The length of a bend beam section can be enlarged, for example, by Widening of the underlying cavity. This will make the Amplitudes of electromagnetic vibrations in relation to the amplitudes of the string vibrations larger. The cross-sectional area of a bending beam section can be enlarged, for example by applying a hard curing adhesive to the bend beam section. As a result, the amplitudes of the electro magnetic vibrations in relation to the amplitudes of the String vibrations smaller. The adhesive is expediently carried out do not apply at the point of the beam section where the string will be carried.

A stringed instrument according to the invention is thus simple regarding the electroacoustic transmission factors of the individual Strings can be individually tuned, even on the string instrument assembled bridge or electric pickup. The vote takes place before the first time playing with the stringed instrument and  does not need to be checked over time under normal circumstances or to be changed. It is understood that a later Change is still possible if changed electroacoustic Transfer factors are desired, without dismantling the Bridge or the electric pickup. The dock for that Stringed instrument is easy and inexpensive to manufacture because it is already a electromechanical converter for converting all string swings sufficient in electromagnetic vibrations and single Lich an electrical channel can be worked. To that extent there is also no need for complex coordination and mixing of the electromagnetic strings from the respective strings electronically. It is also advantageous that a web of a Stringed instrument according to the invention with a hollow acoustic Resonance body trained body can be designed so that the acoustic sound when used without electronic aids is practically not adversely affected.

The electromagnetic transducer can be used as a piezoelectric transducer be executed. A particularly simple and inexpensive to manufacture Embodiment of the stringed instrument according to the invention is thereby characterized in that the piezoelectric transducer made of piezoelectric shear plastic film is formed. To increase sensitivity the piezoelectric plastic film can be folded in a meandering shape.

In a simple embodiment of a string according to the invention instruments is the electric pickup with only one Electromechanical transducer formed, the transducer sections are oriented according to the proviso that both transverse and longitudinal mechanical vibrations of the strings in electromagnetic  table vibrations are converted. - Longitudinal vibration against the strings force transverse vibrations of the bending beams sections in the direction of the longitudinal extension of the strings. Transversal Vibrations of the strings force transverse vibrations of the Bending beam sections perpendicular to the length of the strings. Both transverse and longitudinal mechanical vibrations of the Strings can be converted into electromagnetic vibrations if the transducer sections with respect to the reason mentioned additional directions of vibration of the bending beam sections are angled. In the simplest case, the converter sections angled at 45 ° for the longitudinal extension of the strings. It understands yourself that a coordination of the bending beam sections with respect to their Vibration ability in the direction of the longitudinal extension of the strings and perpendicular to it.

Another embodiment of the stringed instrument according to the invention is characterized in that the electric pickup two has electromagnetic transducers, each string having two transducers sections of different electromagnetic transducers are assigned, all converter sections are oriented according to the proviso that both transverse and longitudinal mechanical vibrations the strings are converted into electromagnetic vibrations and the orientations of transducers associated with a string cuts are angled towards each other. - In the simplest case the two transducer sections assigned to a string to the longitudinal Extension of the string angled at 45 ° and against each other at 90 ° angled. With this embodiment, the knowledge used that the electromagnetic vibrations caused by the are delivered by both electromechanical transducers, both by transverse as well as longitudinal mechanical vibrations  of the strings originate, however, that the electromagnetic vibration different phase positions against both electromagnetic transducers to each other. Electronically, for example wise by summation and by difference of the electro magnetic vibrations of both electromagnetic transducers, the the transverse and longitudinal mechanical vibrations of the Separate electromagnetic vibrations assigned to strings. Here it is helpful to check the vibratory capacity of the bending beam sections the directions of the orientations of the electromechanical transducers agree sections. The bending is advantageous for this beam sections formed like a gable roof. The Bending beam sections through two angled wings educated. The two wings are expediently parallel to aligned with the orientations of the two transducer sections. A Adjustment of the bending beam sections can be done in a simple way, for example by trimming or the like one or both Wings take place. By separating the longitudinal and associated transverse mechanical vibrations of the strings electromagnetic vibrations can create special sound effects produce.

Advantageously, the transducer sections are elastic and shed electrically insulating material. It is understood that the bending beam sections in terms of their ability to vibrate through the elastic material are influenced as little as possible. By the Potting with an elastic and insulating material like For example, silicone rubber or latex are the one Transducer sections protected from damage and on the other hand unwanted mechanical natural resonances of the transducers cuts and / or the bending beam sections reduced.  

Another embodiment of the stringed instrument according to the invention is characterized in that the bending beam sections at least electrically conductive in part of the contact areas of the strings are trained. Such an embodiment allows electrical contacting conductive strings and grounding if necessary to suppress interfering electromagnetic interference. Such electromagnetic interference can be further reduced if the web is partially or completely with a preferred wise high-resistance shielding layer is equipped.

In the following, the invention is based on only one embodiment Example illustrated drawing. Show it

Fig. 1 shows an inventive stringed instrument,

Fig. 2 is a bridge for a stringed instrument according to the invention with strings which are arranged in a plane,

Fig. 3 shows the object of Fig. 2 whose strings are arranged in an arc-shaped curved surface for a stringed instrument,

Fig. 4 is a detail view of the object of Fig. 2,

Fig. 5 shows the subject of FIG. 4, in the section plane AA

Fig. 6 an electromechanical transducer for a fiction, according stringed instrument,

Fig. 7 of the object of FIG. 6 in the section plane BB,

Fig. 8 shows a beam deflection portion which is tuned to a higher resonant skill,

9 is a bending beam portion, FIG. Which matched to lower resonant skill, in cross-section,

Figure 10 sections. A web with gable roof-shaped bending beam,

Fig. 11 shows the subject of FIG. 10 in the section plane CC,

Fig. 12 shows the subject of FIG. 10 with a higher resonant ability in directions of the wings of the gabled bending beam portion,

Fig. 13 shows the subject of Fig. 12 in the section plane DD with reduced vibratory capacity in the direction of the second support surface of the gable-roof-shaped bending beam section.

Is shown in FIG. 1, an inventive stringed instrument in one embodiment as a guitar 1 with the body 2, ceiling 3, 4 neck, a plurality of tensioned strings 5 and a web 6 with an electrical pickup. The web 6 is inserted into a groove, not shown, and is indirectly supported on the ceiling 3 . In this respect, the term web in the context of the exemplary embodiment denotes a web insert. It goes without saying that an embodiment with a web 6 supported directly on the ceiling 3 is also within the scope of the invention.

The web 6 is shown in detail in FIG. 2. One can see a base side 7 of the web, which is supported directly or via an adjusting device (not shown) on the ceiling 3 of the body 2 . A bending beam 8 is arranged opposite the base side 7 with bending beam sections 9 , by which the tensioned strings 5 are carried. The bending beam sections 9 are formed by means of support elements 11 which firmly support the bending beam 8 in the areas between the strings 5 with respect to the base side 7 of the web 6 . Cavities 12 are thereby formed. One can also see an electromechanical transducer 13 which is fastened on the base side and which has tongue-shaped transducer sections 14 , the ends of which are attached to the bending beam sections 9 spanning the cavities 12 . The electromagnetic vibrations generated by the electromechanical transducer 13 are fed to a preamplifier 15 , with which a first amplification of the electromagnetic vibrations is carried out. Adjacent bending beam sections 9 can be separated from one another by incisions 16 , as a result of which better decoupling of the mechanical vibrations of adjacent bending beam sections 9 can be achieved.

FIG. 3 shows a bridge which is basically similar in construction, but for use with stringed instruments 1 , the strings 5 of which are stretched in an arched surface. Such an arrangement of the strings 5 is common, for example, in a so-called western guitar, but also in classic stringed instruments 1, such as a violin.

FIG. 4 shows a detailed view of the object of FIG. 2. It can be seen particularly clearly here that the electro-mechanical transducer 13 is glued on the base side and at the ends of the tongue-shaped transducer sections. In the section plane AA, which is shown in FIG. 5, further details become clear. The string 5 can perform transverse and longitudinal vibrations, which are indicated by arrows. This corresponds to transverse vibrations of the bending beam section 9 in the directions indicated by the arrows. The tongue-shaped wall lerabschnitte 14 of the electromechanical transducer 13 are compared to the length of the string 5 is angled at an angle of approximately 45 °, sections of this orientation of the tongue-shaped Wandlerab 14 thus both longitudinal vibration and transverse vibrations of the strings are converted into electromagnetic waves 5 . In the exemplary embodiment, the electromechanical transducer consists of a piezoelectric plastic film 17 , which is folded in a meandering shape with the interposition of an insulating separating layer 18 . The piezoelectric plastic film 17 is contacted by means of the two electrical lines 20 . The transducer section 14 is potted in the cavity 12 with an elastic and electrically insulating material. To reduce electromagnetic interference on the electro-mechanical transducer 13 6 covers 21 are attached on both sides of the web made of soft high-resistance conductive plastic. This shielding is completed by a conductive area 19 of the bending beam section 9 , which contacts an electrically conductive string 5 . It is understood that the covers 21 and the area 19 are grounded according to the rules of modern electronic electronics.

Fig. 6 illustrates the electromechanical transducer 13 in a tongue-shaped transducer sections 14 and lines 20. Figs. 7 shows the subject of FIG. 6 in the section plane BB in an exaggerated width. It can be seen particularly clearly that the electromechanical transducer 13 is formed from a piezoelectric plastic film 17 , the piezoelectric plastic film 17 being folded once in a meandering manner with the interposition of an electrically insulating plastic film insert 18 . It goes without saying that the plastic film insert 18 preferably has similar mechanical properties to the piezoelectric plastic film. The piezoelectric plastic film 17 and the plastic film insert 18 are connected by gluing.

In the detail view of Fig. 8 can be seen a bending beam section 9 whose oscillation capability is increased by the undercuts 22nd The undercuts 22 increase the effective length of the bending beam section 9 . A bending beam section 9 with reduced oscillation ability can be seen in FIG. 9. By applying an adhesive 23 that hardens with great hardness, the cross-sectional area of the bending beam section 9 is enlarged. The features explained in FIGS . 8 and 9 for tuning the oscillatory speed of the bending beam sections 9 can be easily set up with the web already installed.

FIGS. 10 and 11 show a further embodiment of a stringed instrument according to the invention with a web 6, the bending beam portions 9 gable roof shape from the wings 24, 25 are formed. The wings 24 , 25 are angled at 45 ° to the longitudinal extension of the string 5 and are perpendicular to one another. The web also has two electromechanical transducers 13 , 13 ', the tongue-shaped transducer sections 14 , 14 ' are oriented parallel to the wings 24 , 25 . The mechanical vibrations of the bending beam section 9 are transmitted by means of a coupling element 26 to the ends of the tongue-shaped transducer sections 14 , 14 ', the coupling element 26 having one end in the area of the gable of the bending beam section 9 and the other end to the ends of the transducer sections 14 , 14 'is firmly glued. The two electromechanical transducers 13 , 13 'generate electromagnetic vibrations, which correspond to both transverse and longitudinal vibrations of the string 5 , which are indicated by arrows, but the phase position of the with the longitudinal vibrations of the string correspond to the electromagnetic vibrations by approx shifted half a period. By summing and forming the differences in the electromagnetic vibrations from the electromechanical transducers 13 , 13 ', two electromagnetic signals are obtained, one of which corresponds to longitudinal vibrations of the string 5 and the second to transverse vibrations of the string 5 .

In Fig. 12, a gable roof-shaped bending beam section 9 is shown, in which a cutout 27 in one or both supporting surfaces 24 , 25 is set up for the purpose of coordination with regard to the oscillating ability. A cutout 27 in a wing 24 or 25 increases the ability of the gable roof-shaped bending beam section 9 to vibrate in the direction of the wing 24 or 25 in which this cutout 27 is made. Conversely, as shown in FIG. 13, the ability of the gable roof-shaped bending beam section 9 to vibrate in the direction of an aerofoil 24 , 25 can be reduced by applying an adhesive 28 that hardens with high hardness.

It is understood that the electromagnetic vibrations removed by an electromechanical transducer 13 , 13 'are further processed in accordance with the rules of modern electronic electrical engineering.

In particular, it can be expedient to integrate a high-pass filter with a corner frequency of approximately 100 Hz into the preamplifier 15 or to connect it downstream. If the cut-off frequency is adjustable, for example between approx. 85 Hz and approx. 350 Hz, it can be achieved that in acoustic stringed instruments an electronic reproduction sounds particularly true to life in accordance with the particular sound-forming designs of the resonance bodies. So-called network hum is also reduced.

Claims (12)

1. String instrument, in particular guitar, with body, top, neck, several tensioned strings and a bridge with an electric pickup, the mechanical vibrations of the strings being convertible into electromagnetic vibrations by means of at least one electromechanical transducer, characterized in that
that the electromechanical transducer ( 13 ) has tongue-shaped transducer sections ( 14 ), each string ( 5 ) being assigned a transducer portion ( 14 ),
that the web ( 6 ) has the strings ( 5 ) carrying vibratable bending beam sections ( 9 ) for transmitting the mechanical vibrations of the strings ( 5 ) to the associated transducer sections ( 14 ), each string ( 5 ) or each transducer section ( 14 ) is assigned a bending beam section ( 9 ), and
that the bending beam sections ( 9 ) are individually tunable with regard to their ability to vibrate. 2. String instrument according to claim 1, characterized in that the electromechanical transducer ( 13 ) is designed as a piezoelectric transducer. 3. String instrument according to claim 1 or 2, characterized in that the piezoelectric transducer is made of piezoelectric plastic ( 17 ). 4. String instrument according to one of claims 1 to 3, characterized in that the piezoelectric plastic film ( 17 ) is folded in a meandering shape. 5. String instrument according to one of claims 1 to 4, characterized in that the electric pickup has only one electromechanical transducer ( 13 ), the transducer sections ( 14 ) being oriented according to the proviso that both transver sale and longitudinal mechanical vibrations of the Strings ( 5 ) can be converted into electromagnetic vibrations. 6. String instrument according to one of claims 1 to 4, characterized in that the electric pickup has two electromagnetic transducers ( 13 , 13 '), each string ( 5 ) two transducer sections ( 14 , 14 ') of different electromagnetic transducers ( 13 , 13 ') are assigned, wherein all transducer sections ( 14 , 14 ') are oriented according to the proviso that both transverse and longitudinal mechanical vibrations of the strings ( 5 ) are converted into electromagnetic vibrations and the orientations of a string ( 5 ) assigned converter sections ( 14 , 14 ') are angled against each other. 7. Stringed instrument according to one of claims 1 to 6, characterized in that the bending beam sections ( 9 ) are formed from a single bending beam ( 8 ). 8. Stringed instrument according to one of claims 1 to 7, characterized in that the bending beam sections ( 9 ) are practically decoupled from one another with respect to their ability to vibrate. 9. Stringed instrument according to one of claims 1 to 8, characterized in that the bending beam sections ( 9 ) are formed like a gable roof with two wings ( 24 , 25 ). 10. String instrument according to one of claims 1 to 9, characterized in that the transducer sections ( 14 , 14 ') are cast with an elastic and electrically insulating material. 11. String instrument according to one of claims 1 to 10, characterized in that the bending beam sections ( 9 ) are at least in part ( 19 ) of the contact areas of the strings ( 5 ) are electrically conductive. 12. String instrument according to one of claims 1 to 11, characterized in that the web ( 6 ) is partially or completely equipped with a preferably high-resistance shielding layer ( 21 ).