KR840000181B1 - String instrument pickup system - Google Patents

Abstract

A string instrument pickup system sensitive to 360≰of string movement but which is substantially immune from microphonics. A piezoelectric transducer is compressively associated with vertical movement components of each string of the instrument, but is laterally offset from a centered position under the string for compressive association of the transducer also with horizontal string movement components.

Description

Stringed Pickup Plate System

1 shows the invention in the form of a basic unit associated with bridges and saddle members of a typical acoustic guitar, with the instrument being longitudinally cut along the longitudinal axis and vertically through the bridge and pickup modules of the invention. Partial vertical section view showing one section.

FIG. 2 is an enlarged cross sectional view of the portion taken along the line 2-2 of FIG. 1. FIG.

3 is a partial top view of the depicted structure shown in FIGS. 1 and 2;

4 is a perspective view of the pickup module shown in FIG. 1 and FIG.

5, 6 and 7 are diagrams showing the operating states for the form of the invention shown in FIGS. 1, 2 and 4, respectively.

FIG. 8 is a schematic diagram showing another form of the invention implemented with respect to other string adjusters of the " non-pupillary body " type having six strings.

FIG. 9 is a schematic view similar to FIG. 8 showing another form of the present invention applied to a “non-pupillary body” type guitar having four strings.

TECHNICAL FIELD The present invention relates to the field of string instrument pickup transducers and more particularly to pickups of the type using piezoelectric transducers pressed directly by the strings of the musical instrument.

Electromechanical transducers, ie pickups, are widely used in connection with stringed instruments, in particular in connection with acoustic guitars and "non-pupillary" guitars. Many of these prior art pick-ups are intended to be mounted directly on the strings of the instrument to renew the original sound of the strings and are typically used for coil wound magnetic pick-ups and coil instruments, first used in a "non-pupillary body" type known as an "electric guitar." It includes a piezoelectric crystal pickup that is provided in the form of a separate crystal pressed under each string closest to the bridge.

The fundamental drawback of all of these prior art pickups, which are directly related to the strings of the instrument, is that they do not fully respond to the vibrating movement of the string in all directions, i.e. the 360 ° string movement. Therefore, the conventional coil winding magnetic pickup responds only to the vertical movement of the strings and generally does not respond to the horizontal movement of the holding or bowing instrument. Similarly, most piezoelectric crystal pickups essentially respond only to the vertical movement of the string and thus do not respond to the initial vibration. Since these conventional magnetic and piezoelectric pickups do not sufficiently respond to the horizontal or lateral vibration of the strings, they cause incomplete electrical reproduction of sound wave information generated by the strings, resulting in poor fidelity, and in the case of piezoelectric pickups, the amplitude of the reproduced information. This small size requires the use of a preamplifier in front of a conventional amplifier system.

Another problem with conventional piezoelectric crystal pickups that respond vertically is that the pickup responds to vibration and pressure information of the Helmholtz resonator of the acoustic instrument, so that the pickups are taken from acoustic reflections, other instruments and the voices of other players. It is highly responsive to various morphology "microphonic" or body noises, including the cross-supply of, noises of fingers and chords, and various reflections on instruments.

Coil winding magnetic pickups have another drawback that responds greatly to electrical idle signals, such as "hum" from stage lighting and other electrical devices, and many piezoelectric crystal pickups have a similar problem. Coil wound magnetic pickups have another problem of using special magnetic strings, which are of poor sound quality than conventional strings.

In Evans, U.S. Patent Nos. 3,080,785, 3,154,701 to Seller's 3,396,284 and 3,530,228, conventional examples of piezoelectric crystal pickups of the prior art using separate crystals for respective strings have been described. The crystals in these patents essentially respond to the vertical movement of the string, and the horizontal movement of the string causes a pulsating action in which one side of the crystal is raised and the other side is lowered to offset the string's horizontal information.

Minimizing the volume of each piezoelectric element and microphonic or body noise as in Evans Patent No. 3,073,203, including isolating crystals from the instrument by a vibration-free support as in Recard No. 3,712,951. Several attempts have been made before or to avoid this. Emmans' patent 3,137,754 attempted to eliminate microphonics by providing half of each string crystal of opposite polarity, but this method essentially responds only to the vertical movement of the strings and not the horizontal movement of the strings in general. Scheller's patent 3,453,920 attempted to avoid microphonic by placing each string in the center over a pair of piezoelectric elements of opposite polarity, but this completely eliminates the transducer's sensitivity to the string's vertical movement and reacts only to the string's horizontal movement. do.

Applicants are encouraged to respond to both the vertical and horizontal movements of their strings and to fully respond to the 360 ° string movement and at the same time directly relate to the strings of the stringed instrument which do not actually fully respond to acoustic reflection, body noise, cross-feeding and other forms of microphonic Or know that there is no piezoelectric transducer.

In this field, which considers these and other problems, it is an object of the present invention to provide a string instrument pickup system that responds well to 360 ° string movements.

It is another object of the present invention to provide a string instrument pickup system that does not actually fully respond to various types of microphonic, including acoustic reflections, instrument body noises, cross feeds and the like.

It is yet another object of the present invention to provide a string instrument pickup system that does not actually fully respond to external electrical signals that typically generate "hum" in the prior art pickups.

According to the invention, a series of spaced piezoelectric crystals are arranged laterally in basic unit form under the strings of the instrument associated with the bridges of the acoustic instrument or the string regulators of the instrument in the form of a "non-pupillary body". The polarity of the crystals is such a polarity that half the size of the crystals, ie half area, is polarized in one vertical direction and the other half is polarized in the opposite vertical direction, canceling out all microphonics. Each string is placed pressure on a crystal with one polarity and is widened laterally from a crystal of opposite polarity adjacent to it so that the positive and negative vertical increases in pressure are applied to each string. Minimal adverse reactions to crystals of opposite polarity adjacent to each other, sensed by directly related crystals and off-celled laterally. At least a portion of the crystal that is directly pressure-connected to the respective strings is off-celled laterally from the strings in response to the wave severity generated by the horizontal movement of the strings and this wave effect of some embodiments of the present invention is electrically In addition, it can also be applied to an adjacent opposite polar crystal.

The present invention is a novel basic unit type which is actually fully protected against external electrical signals and allows conventional bridge and saddle members to be used in acoustic strings and conventional string adjusters to be used in string instruments of the "non-pupillary body" type. Also contains crystals.

These and other objects of the present invention will be described in more detail with reference to the following description and attached drawings.

1 through 4 illustrate one embodiment of the present invention used in connection with a six-string acoustic guitar. Acoustic guitars generally have a flat top plate or sound plate 10, which is the upper part of the guitar Helmholtz resonator. Conventional bridge 12, which may generally be made of wood, is attached to the top surface of top plate 10 and has a downwardly open groove 14 which can be directed outwards if bridge 12 is of wood and groove 14 is generally transverse to bridge 12 And generally have a rectangular cross section. The long pick-up module 16 according to the invention is mounted in the groove 14 of the bridge 12. The pickup module 16 also generally has a rectangular cross section and the lower surface of the pickup module 16 is positioned on the top plate 10 and is not affected by the vertical compression force and any other vertical pressure transmitted to the pickup module 16 via the saddle member described below. The upper surface is kept at a distance slightly below the upper part of the groove 14.

The groove 18 extends upwardly from the groove 14 through the remaining upper portion of the bridge 12 to receive and locate a conventional conventional saddle member 20, typically made of corrugated or plastic. The groove 18 extends perpendicularly parallel to the groove 14, ie upwards from the center of the cross section of the groove 14 as shown in FIG. 2 and the length of the groove 18 is slightly smaller than the length of the groove 14. The saddle member 20 is loosely engaged with the groove 18 so that it rests on the upper surface of the pickup module 16 along the entire lower edge of the groove 18 and the loose fit of the saddle 20 and the groove 18 allows the pressure information from the vibration of the strings of the instrument to be removed from the bridge 12. Transfer to the pick-up module 16 through the saddle member 20 without frictional interference.

The six strings 22a to 22f are pulled over the upper edge of the saddle member 20 at positions approximately equal apart and connected to respective anchor pins 24. The sum of the downward force of the strings 22a-22f applied to the pickup module 16 through the saddle member 20 depresses the pickup module 16 with a pressure mechanical bias tension of approximately 40 pounds.

According to a suitable construction, the pick-up module 16 has a long body 26 in the form of a channel member of a conductive material, such as brass, which contributes to the piezoelectric crystal used in the pick-up module 16 as a generally solid support base and also serves as a grounding conductor and an electrical shield. Include. Four flat long piezoelectric crystals 28a, 30a, 28b, and 30b are uniformly spaced apart along the flat bottom of the channel portion 26, and each piezoelectric crystal is placed on the flat surfaces of the channel member. It has a common electrode pair at and responds to pressure vibration in its thickness. The two crystals 28a and 30b at the end are the same size and the more centrally located two crystals 30a and 28b are the same size and twice as large as the crystals 28a and 30b. As shown in FIG. 2, all the crystals have the same thickness in the vertical direction and the same width as the channel member 26 in the transverse direction. As shown in FIG. 1, the crystals 28a and 30b are half the length of the crystals 30a and 28b, as the crystals vary in size or area by making them different lengths along channel subsection 26. .

An important aspect of the present invention is the vertical arrangement of particular strings and pairs of strings associated with each crystal. Therefore, the respective strings 22a and 22f at the end are placed directly above the respective crystals 28a and 30b at the end and the respective strings 22a and 22f at the end are then widely offset in the column direction from the adjacent crystals 30a and 28b respectively. In a similar manner, the respective pair of middle strings 22b and 22c are disposed vertically directly above the crystal 30a and the strings 22b and 22c are then widely offset in the column direction from adjacent adjacent crystals 28a and 28b. In the same way, the respective middle strings 22d and 22e are disposed vertically directly above the crystal 28b and the strings 22d and 22e are then widely offset in the column direction from the adjacent respective crystals 30a and 30b.

This arrangement of crystals of different sizes and the specific vertical arrangements of the strings associated with the respective crystals provide a high sensitivity pickup in response to movement for the respective strings in all directions including the two horizontal and vertical components. The noises of the instrument body, acoustic reflections, cross-feeds from other instruments, and the like that are applied to the crystal cumulatively through the instrument's top plate, ie, acoustic plate 10, at the same time, by changing the polarities of the continuous crystals, are actually completely Offset.

Respective crystals 28a and 28b and 30a and 30b, respectively, show that the voltage difference occurs in one direction between the opposite electrodes in application to the positive increase in pressure in the thickness state and to the negative pressure increase in the thickness state. The voltage difference in the direction is generated between the electrodes. Therefore, for a positive increase in pressure, the first electrode of each crystal will be in a forward direction and the second electrode will be in a negative direction, and for a negative increase in pressure, the first electrode will be in a negative direction and the second electrode will be in a positive direction. Will be. The plus and minus excursions are placed adjacent to the opposite electrodes of the respective crystals of FIG. 1 so as to indicate the polarities of the crystals against the forward increase in pressure, and the same applies to the schematic diagram of FIG. From the polarities varying for successive crystals 28a, 30a, 28b and 30b we see that crystals 28a and 28b have one polarity in the vertical direction and crystals 30a and 30b have the opposite polarity in the vertical direction. Could be. A method of providing a high sensitivity pickup responsive to the direction of movement of all strings (i.e. 360 string movements) while simultaneously completely eliminating noises in response to the accumulation forces applied to the crystals through the top plate 10 is shown in FIG. This will be described in detail in connection with FIGS. 6 and 7.

The electrical connection of the piezoelectric crystal electrode will now be described. A flat layer 32 of insulating material abuts the flat bottom of channel section 26 and is supported on top of insulating layer 32 along most of the length of channel section 26, which may be a metal foil such as copper foil. The bottom electrodes of crystals 28a and 28b and 30a and 30b, respectively, have electrical connections to the thermal conductor 34 over their entire surface. The ground diagram 36, which is a metal foil such as brass, actually covers the top opening of the channel to protect the channel section 26, and the entire surface of the coating 36 is in electrical connection with the upper electrodes of the crystals 28a and 28b and 30a and 30b, respectively. Have Ground Plane Plate 36 is electrically connected to channel subsection 26, so subheads 26 and 36 provide a grounding shield that completely surrounds the crystals, whereby any electrical generated externally, such as 60 cycle noise from a luminaire or other It effectively protects crystals from signals. As shown in FIG. 1, the grounding tube 38 is fitted into the groove through the underside of the channel member 26, and the outer conductor of the coaxial cable 40 is electrically connected to the grounding tube 38, which is connected to the channel part 26 and the ground plate 36. The central conductor of coaxial cable 40 is connected to thermal conductor 34 by soldering, completing the electrical circuit for the crystals. The ground tube 38 and the coaxial cable 40 extend through the holes 42 of the top plate 10 and then the coaxial cable 40 is connected to a suitable connection device such as a "end plug adapter" for connecting to the amplifier disclosed in US Pat. No. 3,935,782. . Since the sensitivity and signal-to-noise ratio of pickup 16 according to the present invention are very large, battery amplifiers are not usually required.

5, 6 and 7 diagrammatically show the operating states for the form of the invention shown in FIGS. The crystal positives in FIG. 5 and the plus and minus signs annualized represent the polarities of the voltage generated by the forward increase in pressure. Since the bottom electrodes of all four crystals are electrically connected to thermal conductor 34, for positive increase in pressure, crystals 28a and 28b provide negative voltage output to conductor 34 and crystals 30a and 30b to forward voltage to thermal conductor 34. Provide the output. Conversely, for a negative increase in pressure, crystals 28a and 28b provide forward voltage outputs to thermal conductor 34 and crystals 30a and 30b provide negative voltage output to thermal conductor 34. Since crystals 28a and 28b plus crystal area are the same size as crystals 30a plus crystal 30b plus crystal area 28a and 28b, the voltage output is shown schematically by the parenthesis arrow indicated in the upward direction of FIG. Likewise all four crystals will generally offset the voltage output of the crystals 30a and 30b for any positive or negative increase in pressure that is normally applied. Instrument body noises, acoustic reflections, cross feeds from other instruments, and similar microphonics provide a constant or negative increase in pressure that is normally applied to all crystals in general, so that the increase in pressure is driven by pickup module 16. In fact it is completely offset.

Nevertheless, the pickup module 16 is very sensitive to both forward and negative increases in pressure provided by the vertical and horizontal components for the motion of each of the six strings 22a-22f and 360 of the respective strings 22a-22f. It is very sensitive to movement. 5 shows how this sensitivity is generated for the vertical motion component of the strings, which are etched, also as solid vertical arrows associated with the respective strings. Since each string 22a-22f is directly above a portion of each crystal, the vertical movement component of each string will provide the crystal with a vertical increase in the surrogate pressure directly to provide a surrogate electrical reflection. Thus, the vertical motion component of string 22a will provide this direct electrical response to crystal 28a and the respective strings 22b and 22c will provide this direct electrical response to crystal 30a and the respective strings 22d and 22e will provide this direct electrical response to crystal 28b. The current 22f provides this direct electrical response to crystal 30b.

However, each of the strings 22a to 22f degrees is placed closest to one of the crystals and spaced apart laterally from the adjacent adjacent crystal of opposite polarity. This transmits the vertical pressure increase from each string to the oblique angle with the opposite polarity of the opposite polarity as shown by the dashed arrow and reduces the small amount of signal.

6 and 7 show how the pick-up module 16 responds to the horizontal, lateral, movement of the strings. The lateral movement of string 22b and string 22b associated with crystals 28a and 30a are representatively shown and each of the other strings performs a similar lateral movement associated with a pair of crystals. The lateral movement of the strings exerts pulsating compression and tension on adjacent crystal pairs to provide additional electrical output. To provide this pulsating effect on the particular crystal on which the string is placed, the string is placed near the edge of the crystal so that the crystal extends greatly laterally from the string. Therefore, it can be seen from FIG. 5 that each string is placed directly on and near one edge of a particular crystal.

As shown in FIG. 6, the left movement of the string 22b causes a positive pressure increase on the crystal 28a disposed to the left of the string 22b and at the same time a negative pressure on the left portion of the crystal 30a disposed to the right of the string 22b. Cause an increase (ie tension). Since the polarity of crystal 30a is opposite to that of crystal 28a, the negative negative pressure increase of crystal 30a provides additional electrical output to the right portion of crystal 22a as shown by these crystal associated plus and minus signs. Conversely, as shown in FIG. 7, the right movement of the current 22b causes positive and negative signs to increase the positive pressure increase on crystal 30 and the negative pressure increase (ie tension) on crystal 28a as opposed to the electrical output of FIG. Provide additional electrical output as shown by

Therefore, FIG. 5 shows how the vertical movement of the string is sensed without the microphone, and FIGS. 6 and 7 show how the horizontal movement of the string is detected. In fact, this vertical and horizontal movement of the strings can be the vertical and horizontal components of the movement of the strings in any direction so that the pickup module 16 responds to all directions of string movements, i.e. 360 ° string movements.

8 and 9 are schematic diagrams showing an embodiment of the present invention used in connection with a non-acoustic body string instrument, which is represented by a non-acoustic instrument, typically an "electric guitar" using a winding magnetic pickup. FIG. 9 shows the invention applied to a six-string musical instrument of this type and FIG. 9 shows the invention applied to a four-stringed instrument of this type.

Referring to FIG. 8, the pickup unit indicated by 16a has a piezoelectric crystal device such as pickup module 16. As shown in FIG. The pickup unit 16a thus has half sized end crystals 28a and 30b and full sized intermediate crystals 30a and 28b, crystals 28a and 28b having one polarity and crystals 30a and 30b having opposite polarity. In this form of the invention, the saddle member is replaced with three string adjusters 44, 46 and 48 that pull over the string. String adjuster 44 supports a pair of strings 50a and 50b, string adjuster 46 supports a pair of strings 50c and 50d, and string adjuster 48 supports a pair of strings 50e and 50f. Each string adjuster has a pair of adjusting legs which are spaced apart at regular intervals and may be screws.

It can be seen from the comparison of FIGS. 8 and 5 that the strings 50a-50f are similarly arranged in relation to the respective crystals as the strings 22a-22f are arranged. The adjusting leg 52 of the string adjuster 44 is attached to the respective crystals 28a and 30a and the adjusting leg 52 of the string adjuster 46 is attached to the respective crystals 30a and 28b and the adjusting leg 52 of the string adjusting unit 48 is the respective crystals. 28b and 30b, and this attachment is applied to the vertical and horizontal movements of the strings 50a to 50f with the same pressure and as described in detail above in connection with FIGS. 5, 6 and 7 with respect to the movement of the strings 22a to 22f. The increase in tension is applied to the crystals.

In a four-string musical instrument in the form of the "non-cavity body" of FIG. 9, four string controls 54, 56, 58 and 60 are used, such as a pair of adjusting legs 52, respectively. Each of the four strings 62a to 62d is disposed in the center of each of the string adjusters 54, 56, 58 and 60 respectively. The pickup unit 16b of the present invention in this form incorporates only a pair of end crystals 64 and 66, one half size polarized in one direction, and three piezoelectric crystals, a full sized central crystal 68 polarized in the opposite direction. Because of the same crystal area of opposite polarity, generally vertically oriented microphonics actually completely cancel out.

Support 70 is placed in pickup unit 16b between end crystals 64 and 6 and center crystal 68, respectively. Each string is generally centered on the respective string adjuster and the adjuster legs 52 closest to one end of each adjuster attached over one of the crystals and closest to the other end of the adjuster are one of the supports 70 rather than the crystal. It is simply attached above and the vertical and horizontal movements of each string 62a-62d are concealed by one of the crystals 64, 68 and 66 as an increase in pressure and tension so that the motions of the strings 62a-62d of the respective strings 62a-62d can be detected. will be. Therefore, the vertical movement of current 62a will be detected by the crystals. Thus, the vertical movement of string 62 seals the left adjuster leg 52 of regulator 54, providing a vertical pressure and tension increase on crystal 64, while the vertical movement of string 62b is perpendicular to crystal 68 through the right leg of regulator 56. The vertical movement of string 62c would apply an increase in the normal pressure and tension to crystal 68 through the left leg 52 of the regulator 58 and the vertical movement of string 62d would be applied to the crystal 66 through the right leg 52 of the regulator 60. Will increase the vertical pressure and tension. The horizontal movement of the strings 62a, 62b, 62c and 62d will have a wave effect on the respective string adjusters 54, 56, 58 and 60 and crystallize the pressure and tension effects corresponding to the strings 62a, 62b, 62c and 62d. And 66 respectively. It will be appreciated that the pressure bias of relatively high crystals resulting from the tension of the strings makes the term "negative increase in pressure" more technically correct, but here is referred to as the "tension" or "tension" increase applied to the crystals. Is used for explanation.

While the instant invention has been shown and described herein in order to contemplate what is the most practical and suitable embodiment, it is to be understood that the invention is limited to the details described herein as other variations may be provided from the instant invention within the scope of the invention. Rather, it should be in accordance with the entire appended claims.

Claims (1)

As described in the present invention and illustrated in the figures, in a string pick-up, a piezoelectric transducer is generally disposed between the string and the body of the instrument and responsive to a pressure change perpendicular to the general plane of the instrument body; A string support device pressure-attached between the string and the piezoelectric transducer to apply a pressure change to the piezoelectric transducer in response to the movement of the string in the vertical direction of the general string to respond to a vertical movement; Due to the movement of the string generally parallel to the general plane, the support device applies a pressure vibration to the piezoelectric transducer, whereby the piezoelectric transducer generally senses the parallel string movement side by side with the string and center. String pick-up comprising the piezoelectric transducer off-cell in a direction.

Images