1. Field of the Invention
The present invention relates generally to guitar pickups and, more specifically, to an improved acoustic guitar pickup system consisting of two components that provide the signal that is representative of the guitar sound, a primary device and a secondary device. The primary device is the piezoelectric pickup array that is situated beneath the saddle of a guitar. The device is designed to detect the bulk of the sound as well as the tonal nuances. The primary device provides minimal ambience. The secondary device makes use of the physically induced charge modulation properties along both the longitudinal and transverse axis of the interconnecting coax cable that runs from the under the saddle pickup system of the present invention to the impedance changing preamplifier to provide ambiance.
The piezoelectric elements are placed in the center between each pair of strings. A six string guitar could use five piezoelectric elements. The vibration shock wave produced by the string actuation is not directly over the piezoelectric element. The vibrations are diffused by the saddle and the offset (between the strings not directly beneath them) elements react to those diffused vibrations which also make them react to the strings vibrating sympathetically. The effect being that the transduced signal produced by the sum of the piezoelectric elements is very much like the instrument that it is installed in without the excessively percussive sound produced by piezoelectric elements placed directly below or below but adjacent to the string.
On each side of a piezoelectric element is a spacer. (See FIGS. 2, 3 and 4.) The spacer is a very important aspect of this invention as it is of a specially selected material which would provide acceptable mechanical compliance without degrading the tonal qualities of the signal. The function of the spacers is to relieve the piezoelectric elements of the total downward loading forces of the strings thus giving greater bandwidth, dynamic range and lower distortion.
It is well known that the under the saddle style pickups, which use individual piezoelectric elements, have problems that appear to be caused by partially or completely malfunctioning elements. The apparent malfunction causes the amplified acoustic guitar to sound uneven from string to string and the unevenness also changes the tonal qualities.
The reason for this malfunction may not be a failed element but a failure of the individual element to couple mechanically to the guitar. For instance, when a pickup is installed, each element may work perfectly, until the strings are tuned and tension is applied to the saddle, then one or more of the piezoelectric elements fail to be active. The reason for this and the cure, which is a subtle but important part of this invention, is as follows: the force of the string in the downward direction on the saddle is not perfectly even from string to string. The bridge and the top have some flexure, which may not be quite the same as the saddle and/or the pickup. The saddle and/or the pickup can bow just enough so that it does not sit perfectly on the pickup. The result is that the saddle bows just slightly so that the bottom of the saddle does not seat perfectly with the bridge. Any air gap at all, above or below the element, will cause the element to appear not to function.
This problem occurs whether there is a pickup installed or not because the saddle is a different material than the bridge. Because of this, the mechanical coupling is less than perfect and affects not only the amplified sound but the acoustic sound as well. That this problem exists as defined here, is not obvious to the pickup manufacturing community which is one of the reasons why it has gone from individual elements to piezoelectric film. One solution to this problem is to use filler such as an RTV Silicon Rubber above and below the under the saddle pickup. Less than one mil (0.001 inch) is all that is needed. The problem with this system is the pickup is not easily removable. Furthermore, a void can still occur in the form of an air bubble. A better approach, as illustrated in FIG. 5, is a material, which is compressible and does not act as an adhesive, but as a compressible gasket that can easily be removed from the system and make the pickup removable as well as replaceable.
This material would do three things:
1. Prevent the mechanical decoupling of the individual piezoelectric elements of the under the saddle pickup.
2. Couple the saddle to the bridge with no void thus making the saddle drive the top more evenly resulting in a more even sound.
3. Absorbing some of the harshness due to mechanical noise of the string being actuated by the fingers or a pick.
This invention also includes an optional auxiliary pickup whose function is to detect the vibrations within the plane of the top. It adds a component that improves the tonalities of the system. The auxiliary pickup is otherwise considered part of the primary system-since the pickup is activated vibrationally.
2. Description of the Prior Art
There are other pickup devices designed for piezoelectric transducer and pickup means. Typical of these is U.S. Pat. No. 4,160,401 issued to Tomioka on Jul. 10, 1979. Another patent was issued to Saito et al. on Jul. 14, 1981 as U.S. Pat. No. 4,278,000.
Another patent was issued to Baggs on Feb. 9, 1982 as U.S. Pat. No. 4,314,495. Yet another U.S. Pat. No. 4,491,051 was issued to Barcus on Jan. 1, 1985 and still yet another was issued on Mar. 1, 1988 to Fishman as U.S. Pat. No. 4,727,634.
Another patent was issued to Turner on Jun. 23, 1992 as U.S. Pat. No. 5,123,325. Yet another U.S. Pat. No. 5,265,513 was issued to Smith on Nov. 30, 1993. Another was issued to Ekhaus on Apr. 5, 1994 as U.S. Pat. No. 5,300,730 and still yet another was issued on Jun. 21, 1994 to Aaroe et al. as U.S. Pat. No. 5,322,969.
Another patent was issued to Vice on Mar. 2, 1999 as U.S. Pat. No. 5,877,447. Yet another U.S. Pat. No. 6,166,309 was issued to Hoshino on Dec. 26, 2000. Another was issued to Hoshino on Mar. 6, 2001 as U.S. Pat. No. 6,198,036.
A string vibration transducer bridge for an electric string instrument including a plurality of string tension mechanism provided side by side in the bridge and which are adjustably movable along the direction of the string and includes a plurality of string supporting electrode parts which are slidably movable along the direction of the string and rotatable along a direction perpendicular to the string, a plurality of independent piezoelectric transducers which each engage with an undersurface of an electrode part, and a plurality of piezoelectric transducer pushing mechanisms for pushing the piezoelectric transducers against the electrode parts whereby the tension of the string may be adjusted by both the string tension mechanism and the transducer pushing mechanism and the vibration from each string is independently sensed.
The present invention provides a piezoelectric transducer and pickup means using the same for electrical string instruments, the transducer comprising a long and flat outer layer of flexible material and a flexible piezoelectric cable which is buried therein and has a center electrode, a piezoelectric layer formed on the outer periphery of the said electrode and an outer electrode formed on the outer periphery of the said layer, the stiffness thereof being enhanced by either using elastomer of the hardness of more than 80 as measured by the Spring Hardness Test Method in the Physical Testing Method for Vulcanizing Rubber of Japanese Industrial Standard (JIS K 6301) as the material for the outer layer, or by plaiting (braiding) metal wires or by winding the outer electrode of the piezoelectric cable in such a manner as to enable it to press against the piezoelectric layer.
A piezoelectric crystal transducer defines a unitary part of a low profile saddle member adapted for interchangeable mounting in the bridge portion of a stringed musical instrument while obviating external modification of the instrument itself In a preferred embodiment of the present invention, the body of the saddle is molded or potted around elongated piezoelectric crystalline bar segments to form a unitary saddle in which the bar segments traverse the substantial length of the saddle in a direction transversely of the extension of the strings over the saddle with hook-up leads or wires extending from one end of the bar for connection to a suitable cable leading to a conventional amplifier or loudspeaker system. The transducer is constructed to respond to stresses produced by string vibrations in one or more dimensions yet is completely shielded from external electrical fields and minimizes interference with the acoustical circuit of the instrument.
A string instrument pickup system sensitive to 360xc2x0 of transverse string movement, which is substantially immune from microphonics, and which has a substantially equal or balanced response to all of the strings. In one form of the invention 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 the horizontal string movement components; and halves of the total piezoelectric transducer area are oppositely polarized so as to cancel out microphonics. In a modular form of the invention a plurality of the piezoelectric transducers are supported in an elongated array by means of a flexible body of electrically insulative material and a pliable outer wrapping of metal foil so that the transducer is conformable to distortions and deformations in string saddle and bridge elements of the instrument between which the modular pickup is compressed whereby the transducers are made substantially uniformly responsive to the strings. In a presently preferred embodiment a two-section split saddle and uneven transverse positioning of crystals relative to strings for each saddle section provide substantially uniform response to all of the strings; and in this embodiment extremely small crystal areas minimize capacitive signal deterioration, and transversely very short crystals improve transverse string vibration response for substantially 360 degrees of transverse string movement sensitivity.
A transducer for a stringed musical instrument incorporating an electrically conductive ground plane, along with a plurality of piezoelectric transducers and a conductive strip. The ground plane, piezoelectric transducers and conductive strip are secured in an elongated unitary structure with the ground plane and conductive strip disposed on opposite sides of the transducers. A conductive shield made of paper with a conductive coating is disposed about the unitary structure and electrical leads connect to the ground plane and conductive strip, respectively.
An electro-mechanical pickup for a stringed musical instrument, such as a guitar, fits in the bottom of the saddle slot of the instrument and provides an electrical output signal representing the vibrations of the strings of the instrument. The electrical output of the transducer is generated by a piezoelectric transducer element having a long, narrow piece of piezoelectric film with an electrode on each face. One electrode of the piezoelectric transducer element is attached to the conductive face of an elongated core. One conductor of a two-conductor electrical output lead is also attached to the conductive face of the core. The core provides electrical contact and a strong mechanical attachment for the output lead. A conductive contact strip is attached to the second electrode of the piezoelectric transducer element, and the second conductor of the output lead is attached to the contact strip. In a variation of the pickup, the second electrode covers substantially all of one face of the transducer element, and the piezoelectric transducer element is wrapped completely around the core with its first electrode attached to the conductive face of the core. Wrapping the transducer element around the core enables the insulating piezoelectric film to provide insulation for the pickup, and enables the second electrode to provide electrical shielding for the pickup, which saves using additional components to provide insulation and shielding. Further variations provide additional electrical output signals, and include an additional piezoelectric transducer element connected to reduce top noise.
A sound-enhancing insert for stringed instruments in general and for guitars, in particular. The insert is readily mountable between the string supporting bridge saddle and the string tie-down members without repair, alteration of, or replacement of instrument parts. One or more rigid members, constructed of metal, wood, rigid plastic or ceramic, are mounted with a top surface of the rigid member contacting a respective string and the bottom surface of the rigid member contacting the sound table of the instrument. The rigid members are preferably mounted within a pliant soft plastic material such as Neoprene for supporting the rigid members in place and making the insert adaptable to different string heights. The rigid members, in their engagement between string and sound table, provide a second reverberation signal, a change in sustain, and a change in timbre, depending upon the particular material used.
A musical device comprises a guitar with a neck and a plurality of strings. A pickup produces electrical output signals related to the frequency and amplitude of vibration of at least one of the strings. An electronic musical effect generator is receptive of the electronic output signal for altering the frequency and amplitude to produce a musical effect. A strain gauge assembly for plurality of axes is disposed on the guitar neck to sense a plurality of axes of strain in that position during use of the instrument. A pick is actuatable by a user for initiating a note on the guitar. A second sensor senses the manual actuation pressure on the pick and another strain gauge assembly for a plurality of axes is disposed on the pick and generates a plurality of control signals corresponding to structural deflections generated during the use of the pick. A controller is responsive to outputs of the sensors for effecting an alteration in the electronic musical effect generator in response to actuation pressure and strain.
The piezoelectric transducer saddle of the present invention is a thin, generally rectangular member that is designed to fit into the bridge slot of a musical instrument such as a guitar. The piezoelectric element is oriented vertically in the saddle and constitutes a structural member of the saddle. I n a first embodiment of the saddle, a piezoelectric element forms the saddle itself. Electrical contacts are engaged to the sides of the piezoelectric element to produce electrical output. A preferred embodiment of the saddle is a laminated structure wherein the laminated layers are disposed vertically, and a vertical layer composed of a piezoelectric material is generally centrally disposed within the laminated structure. A metallic electrical contact is engaged on each side of the piezoelectric material to receive electrical signals generated by the piezoelectric material. In one embodiment, one of the electrical contacts is formed as a metallic layer which rises to the upper surface of the saddle to make contact with the strings of the musical instrument, in order to provide a ground for the metallic musical strings of the instrument. Further embodiments of the present invention utilize multiple piezoelectric elements and shaped piezoelectric elements to produce enhanced performance.
The signal from a piezo-electric transducer in an electro-acoustic guitar is modified by a variable depth notch filter. The notch filter includes two paths between an input and a summation circuit. The signals in the two paths are 180 degrees out of phase and one of the paths includes a bandpass filter. The notch is located at approximately 5 khz. The depth of the notch depends upon either the broadband amplitude or the narrowband amplitude of the signal from the transducer and the depth of the notch is controlled using either feedback or feed forward control.
In a bridge mechanism for a guitar, the bridge main body having a recess for the saddle and an intermediate member between at least one side of the saddle and the recess. A respective recess or concave primarily in the intermediate member directly beneath where each string passes the saddle, and second regions between the depression where the intermediate member contacts the saddle, thereby to reduce transmission of vibration of the strings to the bridge body and direct the vibrations to a pick up disposed below the saddle. In alternate embodiments, the depressions are on the saddle, there is an intermediate member on both sides of the saddle. All the depressions are in the surfaces of the recess facing the saddle.
An electric guitar which is equipped with a piezo pickup wherein the lengths of the strings are not changed by the rotation of the main saddle body in connection with fine tuning and during tremolo performance. The electric guitar has a piezo pickup and has a main saddle body that is held so as to be rotatably adjustable in a back and forth direction about an axle. The main saddle body is held pivotally by a saddle holding member on a base plate on the guitar body. The base plate is installed so as to freely swing with respect to the surface of the guitar body to provide a tremolo effect. The top surface of the piezo pickup constantly contacts the string that is held by the main saddle body, at least during fine tuning, by rotatable adjustment of the main saddle body and in the possible swinging range of the base plate during a tremolo performance, thereby avoiding an out of tune situation during the tremolo performance.
While these acoustic guitar pickup devices may be suitable for the purposes for which they were designed, they would not be as suitable for the purposes of the present invention, as hereinafter described. The present invention, an improved acoustic guitar pickup system consisting of piezoelectric elements that are placed in between each pair of strings. A six string guitar would use five piezoelectric elements. The vibration shock wave produced by the string actuation is not directly over the piezoelectric element. The vibrations are diffused by the saddle. The offset (between the strings not directly beneath them) piezoelectric elements react to those diffused vibrations which also makes them react to the strings vibrating sympathetically. The resulting effect being that the transduced signal produced by the sum of the piezoelectric elements is very much like the instrument that it is installed in without the excessively percussive sound produced by piezoelectric elements placed directly below or below but adjacent to the string.
A further embodiment would include a piezoelectric element outside of either or both of the outer strings the distance being one half of the distance between the inner strings.
This invention is not limited to acoustic guitars. The principles and claims therein could be applicable to other musical instruments.
The improved acoustic guitar pickup system has two components that provide the signal that is representative of the guitar sound, a primary device and a secondary device. The primary device is the piezoelectric pickup that is situated beneath the saddle of a guitar. The device is designed to detect the bulk of the sound as well as the tonal nuances. The primary device does not provide ambience. None of the pickup devices that are positioned under the saddle provide significant ambience by themselves. The two methods commonly used to add ambience is the use of one or more microphones and/or by electronic or mechanical means such as a reverberation system. The-secondary device as used in one embodiment of the invention makes use of the physically induced charge modulation properties along both the longitudinal and transverse axis of the interconnecting coax cable that runs from the pickup to the impedance changing preamplifier. This cable, carefully chosen for qualities that enhance, but not overpower the primary signal, can simulate the ambience that could otherwise be generated from discrete microphones or reverberation devices. It has been determined empirically that the ambience provided is proportionately chosen so its acoustic effect is present without forcing the system into feedback condition, as any kind of microphone is greatly prone to do so, unless operated in a highly controlled manner.
These different sounds that are generated inside the guitar are picked up by the coaxial cable that connects the pickup to the preamplifier by modulating the sound signal from the pickup to create a sound that is more pleasing and representative of the original instrument as well as an appearance of ambience (spatial effect). In addition, the use of this form of intrinsic ambient modulation does not restrict the true dynamic range nor introduce phase distortion and frequency response aberrations that are inherent with the use of external microphone and equalization techniques.
The placement of the piezoelectric elements along with the construction of the selected spacer materials combines to produce another highly desirable property: very high rejection of acoustic feedback. The present invention exhibits a pronounced and measurable xe2x80x9cdirectional couplingxe2x80x9d effect. Sound and vibration generated by the strings and the body of the guitar are strongly coupled to the transducer generating high signal levels, while sounds and vibration that are external to the guitar are weakly coupled to the transducer thus generating very low signal levels. This property allows the present invention to play much louder than existing xe2x80x9cUnder The Saddlexe2x80x9d pickups without encountering acoustic feedback. This property has been demonstrated repeatedly.
A primary object of the present invention is to provide an improved acoustic guitar pickup system consisting of piezoelectric elements that are placed in the center between each pair of strings.
Another object of the present invention is to provide an improved acoustic guitar pickup system that the vibration shock wave produced by the string actuation is not directly over the piezoelectric element.
Yet another object of the present invention is to provide an improved acoustic guitar pickup system that consists of two components that provide the signal that is representative of the guitar sound, a primary device and a secondary device.
Still yet another object of the present invention is to provide an improved acoustic guitar pickup system that the primary device is the piezoelectric pickup that is situated beneath the saddle of a guitar. The device is designed to detect the bulk of the sound as well as the tonal nuances.
Another object of the present invention is to provide an improved acoustic guitar pickup system that the secondary device makes use of the physically induced charge modulation properties along both the longitudinal and transverse axis of the interconnecting coax cable that runs from the under the saddle pickup system of the present invention to the impedance changing preamplifier in order to provide an ambient effect.
Still yet another object of the present invention is to provide spacers of a material having acceptable mechanical compliance which would relieve the total string forces of the saddle on the piezoelectric elements in order to provide greater bandwidth, dynamic range and lower distortion.
Additional objects of the present invention will appear as the description proceeds.
The present invention overcomes the shortcomings of the prior art by providing an improved acoustic guitar pickup system consisting of piezoelectric elements that are placed in the center between each pair of strings. A six string guitar would use five piezoelectric elements. The vibration shock wave produced by the string actuation is not directly over the piezoelectric element. The vibrations are diffused by the saddle and the offset (between the strings not directly beneath them) elements react to those diffused vibrations which also makes them react to the strings vibrating sympathetically. The effect being that the transduced signal produced by the sum of the piezoelectric elements is very much like the instrument that it is installed in without the excessively percussive sound produced by piezoelectric elements placed directly below or below but adjacent to the string.
Another embodiment to further enhance the acoustic sound is to add an auxiliary pickup specifically to detect the transverse vibrations within the plane of the guitar top.
The foregoing and other objects and advantages will appear from the description to follow. In the description reference is made to the accompanying drawings, which form a part hereof, and in which is shown by way of illustration specific embodiments in which the invention may be practiced. These embodiments will be described in sufficient detail to enable those skilled in the art to practice the invention, and it is to be understood that other embodiments may be utilized and that structural changes may be made without departing from the scope of the invention. In the accompanying drawings, like reference characters designate the same or similar parts throughout the several views.
The following detailed description is, therefore, not to be taken in a limiting sense, and the scope of the present invention is best defined by the appended claims.