Electric Stringed Instrument Having Sound Characteristics of Banjos and Guitars

This invention relates in general to electric stringed instruments and, more specifically, to an improved instrument which can selectively produce more variety of banjo sounds and louder banjo sound than previously possible.

Since the development of electric amplification techniques and equipment for stringed instruments many efforts have been made to both produce higher quality sound and to produce new and different sounds than those produced by prior instruments but all attempts have left banjos with a limitation of sound volume significantly lower than electric guitars due to feedback generated by the head of the banjo when the sound vibration of the music causes excessive vibration of the head. Prior electric banjos with wood bodies do not have volume difficulties but lost the banjo sound because the essential taut membrane was discarded. Early attempts at electrically reproducing banjo sounds used a pickup transducer placed in contact with the taut membrane or the string supporting bridge or both. Law, in U.S. Pat. No. 3,780,202, placed the pickup on a movable bracket within the banjo housing to contact the backside of the taut membrane. While this arrangement does very well at picking up the vibrations of the membrane, severe limitations are encountered when the volume is turned up comparable to an electric guitar, the head vibrates more as the volume increases which causes the instrument to feed back. Pickups have been directly attached to the bridge, for example pickups have been clipped to the bridge itself as described by Cronwell in U.S. Pat. No. 2,725,778 or embedded in a foot of the bridge itself as described by Shubb in U.S. Pat. No. 4,450,744. Unfortunately, these arrangements tend to change the vibration characteristics of the bridge, resulting in tone distortion and still have the volume limitations because the head is not sufficiently dampened from excessive vibration at high volume. These distortions or changes in the sound produced by amplification where taken to an extreme by Rizutti who describes in U.S. Pat. No. 3,192,304 a pickup located on the upper surface of the membrane, fastened to the bridge, which produces "new sounds such as no other electric fretted instrument is able to produce". This still leaves the head free to vibrate and cause feedback.

Thus, there is a continuing need for improvements in stringed instruments to provide improvements in the quality of amplified sound and have the capability of producing greater volume without distorting feedback.

The above-noted problems, and others, are overcome by the electric stringed instrument of this invention, which basically includes a normal banjo head made up of a taut flexible membrane mounted on a ring which is then mounted on a solid body. A fretted neck is fastened to the body in a conventional manner and strings extend from an adjustable securing means at the end of the neck over the banjo head to a tailpiece secured to the body. A bridge is positioned between the strings and membrane. One or more recesses are formed in the body below the strings. Electric pickups in the recesses are in contact with the underside of the membrane, one preferably below the bridge and another preferably between the bridge and the neck attachment end of the head. Spaces between the sides and bottoms of the pickups and sides and bottoms of the recesses are at least partially filled with a pad of resilient foam material. The foam beneath the pickups is compressed slightly to maintain the upper surface of the pickups in resilient pressure contact with the underside of the membrane. While foam is preferred, springs could be used in place of the foam, if desired. Preferably a thin sheet of felt is positioned between pickup upper surface and membrane lower surface.

The banjo may be designed with any style of neck, for banjo players or guitar players, mandolin players, etc. The choice of sounds via the tone control, volume control, and pickup switch allow the musician more choices than ever before possible for banjo players. It opens up many possibilities to produce a unique, distinctive and variable sound.

The body may be circular and fit within a normal banjo housing so that the instrument resembles a normal banjo except for the weight of the solid body replacing the normally hollow banjo housing. Alternatively, the body may have a shape corresponding to any desired guitar shape with the banjo head inset into the upper surface and the flexible membrane spaced slightly from the upper body surface. The airspace under the membrane should be closed to the outside so as to dampen the vibration of the membrane and thus reduce feed back.

Details of the invention, and of preferred embodiments thereof, will be further understood upon reference to the drawing, wherein:

FIG. 1 is a plan view, partially cut-away of my electric stringed instrument in the guitar bodied configuration;

FIG. 2 is a vertical section view taken on line 2--2 in FIG. 1;

FIG. 3 is a detail vertical section view through an embodiment using as alternate pickup, taken on a line corresponding to line 2--2 in FIG. 1; and

FIG. 4 is a detail vertical section view through an embodiment having a banjo bodied configuration, taken on a line corresponding to line 2--2 in FIG. 1.

Referring now to FIGS. 1 and 2, there is seen a stringed musical instrument 10 having a solid body 12 in the general configuration of a standard guitar. While body 12 may be formed from any suitable material, wood is preferred for strength, stiffness and optimum resonant characteristics. Secured to the top of body 12 is a tension hoop consisting of a ring 16 which is fastened to a taut flexible membrane 18. Typically, ring 16 is metal and membrane 18 is MYLAR plastic or sheepskin. A plurality of generally "J" shaped bolts 20 extend over ring 16 and extend down into body 12 into nuts countersunk into body 12 from below (not seen in the figures) to hold ring 16 to body 12 in a conventional manner.

A fretted neck 22 extends away from one end of body 12. A plurality of strings 24 are secured to the end of neck 22 by adjustable screws. Strings extend down neck 22 and across membrane 18 to a tailpiece 26 to which they are secured. Tailpiece 26 is held to body 12 by a bolt and nut arrangement 23. A bridge 30 is positioned between membrane 18 and strings 24. As is conventional with banjos, bridge 30 is not fastened to either strings 24 or membrane 18 but is held in place by tension between those two elements.

One or more recesses 32 and 34 are located within body 12, a first recess 32 preferrably beneath bridge 30 and the second recess 34 forward of the bridge. Each recess is adapted to hold a conventional electric stringed instrument pickup 36. Typical of such pickups are those available from Gibson, Fender, EMG, Seymore Duncan, Alembic under the tradename Humbucking, or any other suitable pickup. Spaces between the sides of pickups 36 and the side walls of recesses 32 and 34 are at least partially filled with resilient foam pads 35 to flexibly position the pickup at the center of the recess. The bottoms of recesses 32 and 34 are formed by removable plugs 38 and 40 which can be removed to allow removal of pickups 36 through the underside of body 12. Pressure at pickups 36 on membrane 18 can be varied by the thickness of the foam pads or the extent to which plugs 38 and 40 are inserted. Plugs 38 and 40 may be typically molded from plastic and may be removably held in place by screws (not shown) extending upwardly through the plugs into body 12. Electrical wires (not shown) can be run from pickups 36 out through holes in plugs 38 and 40 or through any suitable holes in body 12. A resilient foam pad 42 is placed between plugs 38 and 40 and pickups 32 and 34, respectively, to gently urge the pickups upwardly into light pressure contact with the underside of membrane 18 which significantly reduces feedback. Preferrably a thin sheet 44 of felt or the like is secured to the upper surfaces of pickups 36 in order to provide positive reduction of feedback, and still allow vibration of the flexible membrane.

Signals from pickups 36 may be directed to a conventional amplification and speaker system. Controls 46 may be provided to adjust the volume and tone of the signals to the amplifier using conventional electrical circuitry. A three-way switch 48 may be provided to select either pickup or use them both together.

FIG. 3 shows in section an alternative embodiment of the pickup arrangement shown in FIGS. 1 and 2 which produces additional variations in the sound produced. In this case, a pickup 52 having a tone bar or anti-feedback bar 54 adjacent to one end is mounted adjacent a side pad 35 and a small bottom pad 43 in the manner discussed above. Significant here is the anti-feedback or feedback eliminating tone bar which further dampens the head and stops the microphone effect. The bridge position is not actually changed but the position of the pickup can be changed to affect its alignment with the bridge.

FIG. 4 shows another variation of my instrument in section, corresponding in general to the section shown in FIG. 2. Here, rather than a body 12 having a configuration of a conventional guitar with a banjo head 14 fastened to the upper surface as seen in FIGS. 1 and 2, the body is a conventionally configured banjo housing 60 having a taut flexible membrane 62 secured to a circular wooden hoop 64. The instrument has the appearance of a normal banjo. Here, however, a circular solid (preferably wooden) insert 66 one or more pickups 36 in recesses 32 and 34 as discussed above is fastened within hoop 64 with the felt layer 44 on the pickups in resilient contact with the underside of membrane 62. The upper surface of the insert 66 is preferably spaced up to about 1/4 inch from the membrane 62. This instrument functions just as the guitar configured instrument shown in FIGS. 1 and 2 but has the outward appearance of a banjo. Further, with properly sized inserts 66, almost any banjo can be converted to an instrument performing in the manner permitted by my invention. This also closes the airspace under the membrane dampening its vibration thus reducing feedback.

While certain preferred arrangements, configurations and materials were detailed in the above description of preferred embodiments, these may be varied, where suitable, with similar results. For example the guitar-appearing embodiment may be shaped to appear as any conventional or unconventional guitar and reinforced plastics or other composites may be used in place of wood if desired.

Other variations, applications and ramifications of this invention will occur to those skilled in the art upon reading this disclosure. Those are intended to be included within the scope of this invention, as defined by the appended claims.