JPH0385600A - Pickup for stringed instrument - Google Patents

Abstract

PURPOSE: To provide independent electric signals corresponding to respective strings while directly responding to the vibrations of strings by using a bridge provided with separated beam for holding the respective strings. CONSTITUTION: A bimorphic piezoelectric element 50 is embedded into a bridge member 70, one part of respective bimorphic piezoelectric elements 50 is extended into any correspondent one of piles 90 at least, and the bimorphic piezoelectric elements 50 are arranged so as to be bent while responding to the vibrations of strings 74. Then, the respective bimorphic piezoelectric elements 50 apply the different electric signals corresponding to the vibrations of strings 74 held by the correspondent beams 90. Thus, the independent electric signals can be applied corresponding to the respective strings while directly responding to the vibrations of strings.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a pickup for a stringed musical instrument, and more particularly to a pickup for a stringed musical instrument using a bimorphic bending element.

The use of piezoelectric pink-ups for electric string instruments, such as electric guitars, is known. A representative patent on this issue is U.S. Pat. No. 3,453,920 (5chere, 196
9), 3.712,951 (Rickard, 19
73), 4,356.754 (Fishman,
1982), 4,378,721 (Kanek.

etaL, 1983), 4,491,051 (
Barcus, 1985), 4.501, 186 (
; kume, 1985), 4,567.805
(Clevinger, 1986).

Despite extensive efforts by various people and companies to develop piezoelectric pick amplifiers for stringed instruments, prior art devices have not been completely satisfactory.

The inventors of the present invention have discovered that the "pressure sensitive" properties of standard piezoelectric pickups do not inherently meet the requirements of an ideal pickup. As described below, the present invention provides “
Using a pickup that is "bending sensitive" instead of "pressure sensitive" solves the main problem of the prior art.

Ideally, a pickup for a stringed instrument should reproduce the vibrations of each string as a separate voltage. To do this, the pickup must have the following properties:

1. The pickup for each string is placed in close proximity to the string so that intermediate structures do not alter or filter the vibrations of the string.

2. The pickup for each string must be properly aligned with respect to the principal plane of motion of the string so that the pickup can precisely sense the vibrations of the string.

3. The pickup of each string must be closely coupled to the string's motion and not pick up the vibrations of other strings.

4. The pickup must be part of the bridge of the instrument. This is because this is where the vibrations are transmitted to the body of the acoustic instrument.

5. The pickup is mounted in the usual manner across the strings of the instrument, i.e. across the bridge by a small notch in it for each string, so that the player can easily attach it to the instrument in the usual way. It must be possible to change the strings.

Obviously, these conditions or properties of an ideal pickup are somewhat consistent.

The requirement that each pickup must sense the vibrations of only one string is derived, in part, from the MIDI specification for music synthesizer controllers, which means that the isolated input signal for each sound generator within.

Most commercial pickups are deficient in one or more of these properties, which partially explains the known differences in sound quality between electronic and acoustic instruments. For example, the electromagnetic pickups used in standard electric guitars are not attached to the bridge of the guitar.

In some places, those pickups do not produce separate signals for each guitar string.

Prior art includes bridge-mounted piezoelectric sensing pickups for electronic violins, but these pickups are usually mounted away from the strings, or in an arrangement where the coupling to the strings is at the end, or when the strings are replaced. making it difficult.

Additionally, the characteristics of these pressure sensitive pink-ups (ie, the quality of the signal produced) are adversely affected by vibrations across the pickup element.

For example, referring to FIGS. 1A and 18, if the string 10 passes through the notch 12 in the bridge 14 of the instrument and the pressure sensitive pickup 16 is embedded within the bridge 12 (i.e., within the cavity 18 or 20). , the coupling is unsatisfactory regardless of the location of the pink-up element. This is because the speed of sound in the bridge is so high that the transmitted string vibrations cause the entire pickup element to vibrate rather than apply vibration pressure to it. If the pickup is placed under the bridge leg, because it is away from the strings, the bridge structure will unsatisfactorily filter string vibrations and dampen important high frequency components of string vibrations.

Looking at the top view of the violin or cello pickup shown in FIG. The string 10 must be pressed against the pickup at a position where the string vibration is perpendicular to the surface. In FIG. 1c, the pickup assembly 21 for one string is shown, placed on the brissaugier 4 of the instrument. The pressure sensitive piezoelectric element 22 is mounted on an aluminum support 26. ) (-) is encased in a cylindrical hard plastic member 24 which is held in place.
1, the vibration of the string 10 directly translates into a pressure change in the piezoelectric element 22. This allows the pickup to create a good waveform, but the string 10 must bend a little where it intersects the pick amp so that the tension in the layer forces it against the pickup 21. . Placing the bridge 14 and the tail piece 30 that holds the end of the string in such a way as to create such a bend makes it difficult to mount the string on the instrument and creates problems in tuning the string.

The present invention is based on the observation that prior art piezoelectric pickups use pressure-sensing elements and that it is difficult to properly couple the string vibrations of a bowed or plucked string instrument to these pressure-sensing elements. . From one point of view, pressure sensing elements are inherently unsatisfactory. This is because the nature of the musical tones and sounds generated by the strings in stringed instruments is vibratory and not fluctuating pressure.

Therefore, the main object of the present invention is to provide a pickup for a stringed instrument that responds directly to the vibrations of the strings of the instrument. Another object of the present invention is to provide a pick amplifier that produces independent electrical signals for each string of an instrument.

Generally speaking, the present invention is a pickup for a stringed instrument having multiple strings. The pickup has a surface and a bridge supporting the string at a predetermined location along the surface, and a pickup embedded in the bridge member at a location corresponding to the predetermined location along the surface of the bridge member. It includes a plurality of bimorphic piezoelectric elements and connecting wires for carrying electrical signals generated by the bimorphic piezoelectric elements.

Each bimorphic piezoelectric element has two oppositely polarized piezoelectric layers separated by a metal layer. The bimorphic piezoelectric element is embedded in the bridge member, and the main direction of vibration of the corresponding string is perpendicular to the metal layer separating the two piezoelectric layers of the bimorphic element. As a result, the vibration of each string bends a corresponding element embedded within the vessel, so that the pickup responds directly to the vibrations of the strings of the instrument.

In a preferred embodiment, each string is separated by a notch or groove so as to isolate each bimorphic element from the vibrations of the other strings, thereby creating distinctly different electrical signals in response to the vibrations of each string. It has a separate support for.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be explained below with reference to the drawings in accordance with embodiments thereof.

The present invention uses a bimorphic piezoelectric element as a pink-up embedded in the instrument's prefix instead of a pressure-sensitive piezoelectric pickup.

The structure of a bimorph piezoelectric element (sometimes referred to herein as "bimorph") is shown in FIG.

Bimorph or bimorphic piezoelectric elements used in the present invention have various names, including piezoelectric benders, piezoceramic benders, and bilayer piezoelectric elements.

As shown in FIG. 2, bimorph 50 comprises two layers 52 of oppositely polarized piezoelectric material arranged in a sandwich configuration with a metal layer 56 separating the two piezoelectric layers.
and 54 and metal electrodes 5 on the outer surfaces of the two piezoelectric layers.
8 and 60. When the bimorph is bent by applying an unbalanced force on the two sides of the bimorph, one of the piezoelectric layers is compressed and the other is placed in tension (ie, relative to the other layer). Since the two piezoelectric layers are oppositely polarized and connected in series, this opposite stress in each layer creates an electrical output of the same polarity in the wire.

The electrical output of the bimorphic piezoelectric structure at output lines (ie, conductive wires) 62 and 64 is the sum V of the outputs of the two piezoelectric layers.

Generally speaking, the voltage ■ generated by the piezoelectric element 59 is:
It is proportional to the magnitude and direction in which the element is bent. As a result, the bimorphic piezoelectric element 50 is subjected to vibrations and the output voltage produced by the element 50 is a waveform that tracks the strength and frequency characteristics of the vibrations. Additionally, bimorphic piezoelectric elements are sensitive to frequencies above the 20 kHz frequency range that is audible to humans, and therefore are well within the frequency range required to sense frequencies in stringed instruments (i.e., 1
0 20.000 kHz).

Bimorphic piezoelectric elements are commercially available (Piezo Electric Products
(in Metuchen NJ), voltages where the slightest deflection is typically a very sensitive detector of vibrations;
It typically generates orders of magnitude.

In FIG. 3, a violin or upper bridge 70 is shown. Four piezoelectric pickups 72 are embedded within the bridge 70, each with a corresponding string 7.
It is directly below 4. Biomorphic piezoelectric elements are very sensitive and even very small elements produce excellent signals. As a result, it is possible to insert the bimorphic element into a standard violin bridge and use this improved bridge in acoustic violins. In this way, even violins with pickups with built-in amplifiers,
You can make a violin that is also an electronic violin.

To embed the biomorphic element within the bridge 70, approximately 1-
21) are cut, and a bimorphic piezoelectric element of corresponding width is inserted into each slit in the bridge 70.

The bimorphic piezoelectric elements 72 are arranged such that the metal plane 56 (FIG. 2) of each element 72 is perpendicular to the principal plane of vibration of the corresponding string. Since it lies generally laterally in the principal plane of vibration of each violin string and coplanar with the curved upper surface of the bridge 70, the bimorphic elements 72 are aligned with the ending radial line at each of the string notches 76 (
match). Each bimorphic piezoelectric element 72 generates a voltage that is proportional to the amount that the element is bent, and this voltage is transmitted through a pair of wires 78. However, although piezoelectric elements 72 produce superior voltage signals, they produce very little current. Accordingly, the voltage produced by each bimorphic element 72 of wire 78 is amplified by operational amplifier 80 to produce a set of useful output signals.

The amplifier 82 shown in FIG.
It has four operational amplifiers 80 for amplifying the output signals generated by the two. The amplified output signal produced by amplifier 82 on wire 84 is suitable for use as an input signal to an audio amplifier or music synthesizer.

In the preferred embodiment, four operational amplifiers 80 in amplifiers 82 are mounted on a printed circuit board and
This disk is coupled to bridge 70 to reduce the length of wire 78, thereby reducing the chance of introducing noise into the amplified signal.

Another feature of the preferred embodiment shown in FIG. 3 is the decoupling of some of the pickups 72 in the bridge 70. This is accomplished by using a bridge 70 with separate beams 90 to support each string 74. The groove 92 between the girders 90 is
Deep enough, the pickup 72 is recessed high enough within each ridge so that the center of each bimorphic piezoelectric element 72 is above the bottom of the adjacent groove.

Generally, the bimorphic element 72 has a corresponding digit 9
It must extend deep enough into the digit 0 to be bent by vibrations in digit 90, but not by vibrations in other digits. In preferred embodiments, the entire length, or substantially the entire length, of each pickup element is above the bottom of an adjacent groove. As a result, each pickup is coupled only to the string attached to the girder 90 in which it is embedded, and is uncoupled from strings attached to other girders. In other words, the vibrations from each individual string have very little spread to the output of the pickup relative to the other strings.

Decoupling the pick amplifier for different strings is very important when using an electric violin or cello as a control sensor for a synthesizer. Decoupling the 0 string pickup is necessary because if each string is used to control the different tonal aspects produced by the synthesizer, such uncoupling is necessary. , which is desirable for amplified or electronic stringed instruments. This is because it allows the player to adjust the loudness and timbre of each string individually, allowing the instrument to be tuned to have an even sound on all layers. It is from.

FIG. 4 shows waveforms generated by a bimorphic piezoelectric pickup mounted within the bridge of a cello according to the present invention. It is known that the waveforms of violin and cello string vibrations are sawtooth functions of time. Since pymorphic pickups according to the present invention create a sawtooth waveform, this indicates that these pick amplifiers accurately sense string vibrations. The vibrations superimposed on the sawtooth waveform shown in FIG. 4 also match the known characteristics of violin and cello string vibrations.

Although the invention has been described with respect to a few specific embodiments, this description is illustrative of the invention and should not be considered as limiting the invention. Various modifications may be made by those skilled in the art without departing from the true spirit and scope of the invention as defined by the appended claims.

For example, in some applications (e.g., stringed instruments having two or more strings tuned to each tone produced by the instrument), each support bar 90 of the bridge member may be
It may be used to support a set of related strings. Obviously, this variant of the invention can only be used in situations where the combined vibration signal generated by the pickup for each set of strings is useful on its own, i.e. without reference to the vibrations of the individual strings. Must.

[Brief explanation of drawings]

1A, 1B, and 1C are schematic diagrams of pressure-sensing piezoelectric pickups for stringed instruments, FIG. 2 is a perspective view showing the structure of a bimorphic piezoelectric bender sensor, and FIG. 3 is a diagram for each violin string. FIG. 4 is a schematic diagram of a violin bridge with a bimorphic piezoelectric pickup mounted in a cello according to the invention, and a set of amplifiers for amplifying the signal generated by the pickup. FIG. 3 is a time-related curve diagram of a waveform generated by up-setting. 50-Bimorphic piezoelectric element, 52.54-piezoelectric layer, 56-metal layer, 8.60-metal electrode, 2.64-wire, o-bridge, 2-pickup, 4-string, 6- Notch, 8--wire, 0--operational amplifier, 2-amplifier, 4-wire, 0--groove, 2-groove. 4 F~, 3 Engraving of drawings (no change in content) ■ Time (millimeter)) Procedural amendment (method) % formula % 1. Indication of case 1999 Patent Application No. 217169 2. Title of invention For stringed instruments Pick-up 3: Person making the amendment Relationship with the case Applicant 4, Agent 5, Date of amendment order: 28th January 2016

Claims (3)

[Claims] (1) A bridge member having a surface and supporting the strings of a musical instrument at a predetermined position along the surface, and a location corresponding to the predetermined position along the surface of the bridge member. A pickup for a stringed instrument having a plurality of strings, the pickup having a plurality of bimorphic piezoelectric elements embedded in the bridge member, the bridge member including a plurality of girders, and separated by grooves between the girders, The bimorphic piezoelectric elements are embedded in the bridge member such that at least a portion of each bimorphic piezoelectric element extends into a corresponding one of the digits, and the bimorphic piezoelectric element is responsive to vibrations of the string. 1. A pickup for a stringed instrument, characterized in that each bimorphic piezoelectric element provides a different electrical signal corresponding to the vibration of a string supported by a corresponding spar. (2) A bridge member having a surface and supporting the strings of a musical instrument at a predetermined position along the surface, and a location corresponding to the predetermined position along the surface of the bridge member. In the multi-string stringed instrument pickup having a plurality of bimorphic piezoelectric elements embedded in the bridge member, the bimorphic piezoelectric elements are arranged in two oppositely polarized elements, each separated by a metal layer. a piezoelectric layer, the piezoelectric element is embedded in the bridge member with the metal layer substantially coplanar with the corresponding string, and the pickup bends in response to vibrations of the strings of the musical instrument to generate electricity. A pickup for stringed instruments that is characterized by generating a signal. (3) In pickups for stringed instruments with multiple strings,
a bridge member having a plurality of separate cantilever beams, each beam having means for supporting one string, and a plurality of bimorph piezoelectric elements, one bimorph piezoelectric element in each of said beams. A pickup for a stringed instrument, characterized in that the bimorphic piezoelectric elements are arranged so as to bend and generate an electric signal when a string embedded in the string and supported by a corresponding beam vibrates.