CA2792009C

CA2792009C - A hybrid string musical instrument and a method of constructing the same

Info

Publication number: CA2792009C
Application number: CA2792009A
Authority: CA
Inventors: Donald I. Lee
Original assignee: Individual
Current assignee: Individual
Priority date: 2012-10-02
Filing date: 2012-10-02
Publication date: 2015-10-06
Anticipated expiration: 2032-10-02
Also published as: CA2792009A1

Abstract

A hybrid string instrument, integrating an acoustic guitar with a second string instrument of a comparable or a smaller size. The guitar is modified with a cut-out cavity, within which the second string instrument is accommodated. A sidewall segment, which is contoured congruently with the sidewall section of the second instrument that is embedded within the cut-out cavity, is fitted and affixed to the edge of the cut-out cavity. A section of the second instrument is embedded within the cut-out cavity-the embedded sidewall affixed to the sidewall segment fitted to the cut-out cavity-so that the soundboards of the two instruments are coplanar and the planes of symmetry of their necks parallel. A plurality of coinciding apertures is disposed in the adjoined sidewalls of the two instruments, permitting acoustic communication between the two bodies. A truss member braces the head block of the guitar against its tail block.

Description

A HYBRID STRING MUSICAL INSTRUMENT AND A MEHTOD OF CONSTRUCTING THE SAME
FIELD OF THE INVENTION
The present invention relates generally to musical instruments and particularly to a hybrid string instrument combining a modified, ordinary acoustic guitar with a second string instrument of a comparable size or smaller, such as a banjo, a ukulele, or a mandolin.
BACKGROUND OF THE INVENTION
The attractive richness of a multi-player, multi-instrument musical performance is impossible to replicate in real-time in a solo performance. To add tonal variety to their performance, musicians who are proficient on more than one instrument may switch between instruments for different pieces or compositional segments, but must do so during sufficiently long intervals. A
satisfactory solution to the challenge, facing a soloist, of rapidly and seamlessly switching between musical instruments has proven elusive.
In the realm of plucked string instruments, to facilitate, at least in effect, the transitioning between two or more such instruments, hybrid instruments have been devised, which may be categorized broadly into three main types, as follows.
Hybrid string instruments of the first type feature a unitary body and soundboard commonly shared between multiple necks. An example of an instrument of this type is patent US1634730A
(Travaglini; 1927), which teaches the merging of a guitar body and a banjo body as a unified instrument. Patent US1828315A (Cavicchioli; 1931) is another example, featuring a similar merging of two stringed instruments, with the addition of an adjustable partition which separates the common sound chamber into two compartments.
A serious disadvantage of hybrid instruments of this type is that their common soundboard restricts how distinctively the merged instruments sound.
Hybrid string instruments of the second type feature a host instrument into which another, typically smaller, instrument is fully or partly embedded, or onto which it is externally affixed, each instrument retaining its own (possibly modified) body. Patent US1022031A
(Larson; 1912) is an example of an instrument of this type, featuring an acoustic instrument that is partly embedded into another. Larson employs a unitary soundboard and bridge shared between two necks and string sets, but provides distinct bodies and soundholes. Patent US4987815A
(Shockley; 1991) is another example, featuring an acoustic guitar that is fixedly coupled by its sided wall to a solid-bodied electrical guitar, both instruments sharing a unitary soundboard.
Patent US5212329A
(Woodworth; 1993) teaches a means by which a specially contoured electrical guitar may be fastened to an acoustic guitar.
Electrical guitars may be made sufficiently small to be conveniently affixed externally to an acoustic guitar, where the distinctive tone of each instrument remains largely intact. An acoustic instrument of ordinary dimensions, however, must be at least partly embedded within the host guitar for the combination to be of a manageable size. When combined in this manner, if a unitary soundboard is used, as in the first example above, tonal distinction cannot be faithfully preserved.
Hybrid string instruments of the third type integrate two acoustic instrument bodies with a single, shared neck, and provide some means by which string vibrations can be directed to the desired body. Patent US1607449A (Edwards; 1926) is an example of an instrument of this type, featuring a banjo mounted pivotally upon a guitar in such a manner that ordinarily the two instruments are spaced apart slightly, and bridge vibrations are transmitted solely to the banjo head, but by pressing the banjo body against the guitar body, bridge vibrations are transmitted directly to the guitar soundboard. Another example is seen in patent 3633452A
(Beasley; 1972), which features an acoustic guitar whose soundboard is adapted to accommodate an embedded a banjo body. Beasley teaches a unique pivotable bridge which may be set to transmit string vibrations either to the banjo or directly to the guitar.
Although compact and permitting a rapid transition between instruments, these devices suffer from the added complexity introduced by the vibration redirection mechanism, but more importantly, from the limitation imposed by using the same string set for both instruments.
It appears that the challenge of conveniently and seamlessly transitioning between multiple string instruments has not hitherto been satisfactorily met. The present invention addresses this challenge.

- 2 -SUMMARY OF THE INVENTION
It is the first, principal object of the present invention to provide a hybrid instrument combining two acoustic string instruments in a manner which allows rapid, seamless transitioning between the two instruments.
A second object of the present invention is to provide a hybrid instrument that fulfills the first object, in which the distinctive tonal quality of each of the combined instruments is preserved.
A third object of the present invention is to provide a hybrid instrument that fulfills the aforesaid objects, which is of a convenient overall size.
A forth object of the present invention is to provide a method of construction of a hybrid instrument that fulfills the aforesaid objects, which may be executed simply without requiring the specialized skill and tools of a luthier, and is cost-effective.
These objects are met in the present invention through several features, as outlined below.
In its principle aspect, the present invention features the integration of an acoustic guitar with another, preferably smaller acoustic instrument, so that their respective necks are proximal and oriented similarly, and their soundboards substantially coplanar.
A second aspect of the present invention is the coupling of two acoustic instruments, whose bodies and soundboards remain distinct.
A third aspect of the present invention is the partial embedment of one acoustic instrument within the other, which permits the hybrid instrument to be sized conveniently for storage, transportation and playing.
A forth aspect of the present invention is the technique of adaptation and integration of existing, ordinary instruments, which provides a hybrid instrument having the aforesaid features.
These and other objects and features of the present invention are fully expounded hereinafter in the description of the preferred embodiment, in which references are made to accompanying drawings, described next.
DESCRIPTION OF THE DRAWINGS
Fig. 1 A perspective view of the preferred embodiment of a hybrid instrument according to the present invention.

- 3 -Fig. 2 A perspective view of the hybrid instrument of Fig. 1.
Fig. 3 A perspective view of the guitar element of the hybrid instrument of Fig. 1 in isolation.
Fig. 4 A perspective view of the guitar of Fig. 3 with its soundboard and bridge, fretboard and strings hidden.
Fig. 5 A perspective view of the banjo element of the hybrid instrument of Fig. 1 in isolation.
Fig. 6 A perspective view of the guitar element in isolation in an alternative embodiment of a hybrid instrument according to the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENT
The preferred embodiment of the hybrid instrument according to the present invention is depicted in Fig. 1 and Fig. 2 denoted generally by the numeral 1. Hybrid instrument 1 consists of two main elements: a modified acoustic guitar, denoted 2, and a modified resonator banjo, denoted 3.
Referring to Fig. 3 and Fig. 4, guitar 2 is adapted with a shoulder cut-out within which, in hybrid instrument 1., a section of the body and resonator of banjo 3 is embedded. To minimize the overall size of hybrid instrument 1, the cut-out cavity extends into the body of the guitar part-way as deeply as it is possible without appreciably degrading the acoustical qualities of the guitar. It has been found that a cut-out cavity which extends as far as, or slightly beyond the soundhole perimeter still yields satisfactory results.
The cut-out cavity is defined by arcuate line 2.1, cut through and along soundboard 2.2, straight lines 2.3, cut through and perpendicularly to soundboard 2.2 partway along rib 2.4, and contoured line 2.5, cut through and along the remaining section of rib 2.4 underlying the cut-out cavity. Arcuate line 2.1 has a curve radius identical to the outer radius of the sidewall of the resonator of banjo 3; cut lines 2.3 extend to such a depth that banjo 3 is set, in hybrid instrument 1, with its soundboard substantially coplanar with that of the guitar; cut line 2.5 is contoured congruently with the curvature of the back of the resonator of banjo 3, so that the remaining section of rib 2.4 underlying the cut-out cavity has a height profile which, in hybrid instrument 1, allows it to continuously abut the back of the resonator.

- 4 -As will be appreciated by the skilled artisan, banjo 3 may be set with its soundboard offset from the plane of soundboard 2.2 of guitar 2, if such positioning is believed to offer superior playability, structure, or aesthetics, by altering the depth of cut lines 2.3 accordingly.
A concave sidewall segment, denoted 2.6, is fitted and bonded to the edge of the cut-out cavity along soundboard 2.2 and, vertically, along rib 2.4. Sidewall segment 2.6 closes the opening in rib 2.4 created by the cut-out cavity, and provides an attachment surface, in hybrid instrument 11, onto which the embedded section of the resonator sidewall of banjo 3 is bonded or bolted.
In the preferred embodiment, sidewall 2.6 is set, prior to installation, with a permanent curvature which substantially corresponds in radius to that of the cut-out cavity. Using a bending iiron jig is one, well-known technique by which such adaptation may be achieved. Pre-setting sidewall 2.6, at least approximately, to the needed bonding curvature eliminates post-installation stress, which may, in time, compromise its bonding to guitar 2 and banjo 3.
A plurality of radial apertures, collectively denoted 2.7, is disposed in sidewall segment 2.6, which, in hybrid instrument 1, lie in registration with a corresponding set of apertures in the resonator of banjo 3 (discussed hereinafter). Registering apertures 2.7 and 3.2 effectively enlarge the sound box of guitar 2 and banjo 3, in hybrid instrument 1, thus enhancing their tone.
It will be clear to those skilled in the art that sidewall 2.6 may be constructed of various types of solid or laminate wood in a range of thicknesses. It may be of planiform geometry, provided it can withstand the flexing necessary for installation.
To compensate for the slight structural weakening of the body of guitar 2 caused by the shoulder cut-out, an extensible truss member, denoted 2.8, is used to span the guitar body longitudinally, and brace head block 2.10 against tail block 2.11. Truss member 2.8 comprises two metal tubes, each threaded at one end thereof, and an elongated barrel nut 2.9, by which the two tubes are adjustably connected. Head block 2.10 and tail block 2.11 are each adapted with a shallow circular depression of such diameter that it may tightly receive an end section of the respective tube of truss member 2.8. During construction of hybrid instrument 1, truss member ?2.8 is first set with its two tubes screwed approximately halfway into barrel nut 2.9¨their threaded ends abutting. One end of truss member 2.8 is then inserted into one of the aforesaid block depressions, and the two tubes unscrewed with respect to barrel nut 2.9 to drive the opposite end into the depression in the opposite block, and bear forcefully upon it.

- 5 -As will be apparent to the skilled technician, solid wood or aluminum rods may be used instead of metallic tubes. Alternative, equally effective configurations of truss member 2.8 are possible, such as (but not limited to) telescopically engaged tubes, or a single rod/tube lodged at one end thereof in one of the aforesaid block depressions, and carrying an elongated barrel nut at the other end, where the barrel nut itself is lodged in the opposite block's depression.
Referring to Fig. 5, banjo 3 is of the type known as a resonator banjo. In hybrid instrument 1, as described above, a section of the body and resonator of banjo 3 is embedded within the shoulder cut-out of guitar 2. The embedded sidewall section of the resonator, denoted generally 3.1, is bonded (or bolted) to sidewall segment 2.6 of guitar 2, so that the necks of the two instruments are oriented similarly¨their planes of symmetry substantially parallel. Resonator section 3.1 is adapted with a plurality of apertures, collectively denoted 3.2, which are disposed coincidentally with the aforementioned corresponding set of apertures 2.7 in sidewall segment 2.6 of guitar 2. Apertures 3.2 are sized to maximize acoustic communication between the bodies of guitar 2 and banjo 3 without compromising the structural integrity of either instrument.
The embodiment of the foregoing description provides back support for banjo 3, which solidifies its mounting to guitar 2. Keeping the back of guitar 2 intact, however, limits the overall height of banjo 3 (body and resonator) to approximately that of guitar 2. In an alternative embodiment of hybrid instrument 1, guitar 2', depicted in Fig. 6, is adapted with a cut-out cavity, which extends throughout its body¨soundboard through back. This open-back arrangement permits a wider choice of banjo types to be used, as well as other string instruments having an outer sidewall which is perpendicular to their soundboard (to serve as a mounting platform), such as, but not limited to a mandolin or a ukulele. Sidewall 2.6', in this embodiment, spans the full body height of guitar 2', and apertures 2.7' are disposed at such height that when in registration with the corresponding apertures of the embedded instrument, the soundboards of the two instruments are coplanar.
It is to be understood that the forgoing description of the preferred embodiments of the present invention and the accompanying drawings are intended to better elucidate the invention by way of examples, and not in any way to narrow its purview or the scope of the appended claims to the embodiments exemplified.

- 6 -

Claims

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE PROPERTY OR PRIVILEGE
IS
CLAIMED ARE DEFINED AS FOLLOWS:

1. A hybrid string musical instrument comprising:
(a) an acoustic host guitar comprising:
(i) a cut-out cavity, having a cross-section that is delineated by an outer line segment, which is contoured congruently with a shoulder and/or side edge of the soundboard of said guitar, and by a complementary inner line segment, which is contoured congruently with the sidewall section of the resonator of a string instrument appended thereto which is embedded therein, which cavity extending perpendicularly through the guitar soundboard and partway into its body to such a variable depth that the remaining underlying rib section assumes a height profile permitting continuous abutment with the back of said embedded appendant instrument;
(ii) a sidewall segment that is fitted and affixed to the cut-out edge in the soundboard, and the contiguous rib edges;
(b) an appendant acoustic string instrument of a body height comparable to, or smaller than that of said host guitar, having an outer sidewall which is perpendicular to its soundboard, selected from the group consisting of a banjo, a ukulele, and a mandolin;
wherein said appendant instrument is embedded, in part, within said cut-out cavity of said host guitar-the embedded section of said perpendicular sidewall thereof affixed to said fitted sidewall segment of the guitar-the rib section of the guitar underlying the cut-out cavity being in continuous abutment with the back of the appendant instrument, the soundboards of the two instruments being substantially coplanar, and the planes of symmetry of their necks substantially parallel.

2. A hybrid string musical instrument comprising:
(a) an acoustic host guitar comprising:
(i) a cut-out cavity, having a cross-section that is delineated by an outer line segment, which is contoured congruently with a shoulder and/or side edge of the soundboard of said guitar, and by a complementary inner line segment, which is contoured congruently with the sidewall section of the resonator of a string instrument appended thereto which is embedded therein, which cavity extending perpendicularly and coextensively throughout the guitar body;
(ii) a sidewall segment that is fitted and affixed to the cut-out edge in the soundboard, rib, and back of the guitar;
(b) an acoustic appendant string instrument of a body height comparable to, or smaller than that of said guitar, having an outer sidewall which is perpendicular to its soundboard, selected from the group consisting of a banjo, a ukulele, and a mandolin;
wherein said appendant instrument is embedded, in part, within said cut-out cavity of said host guitar¨the embedded section of said perpendicular sidewall thereof affixed to said fitted sidewall segment of the guitar¨the soundboards of the two instruments being substantially coplanar, and the planes of symmetry of their necks substantially parallel.

3. The hybrid musical instrument defined in claim 1 or 2, wherein said fitted sidewall segment of said host guitar and the section of said perpendicular sidewall of said appendant instrument that is affixed thereto having a plurality of registering apertures, thereby to permit acoustic communication between the two instruments.

4. The hybrid musical instrument defined in claim 1, 2, or 3, wherein said host guitar further comprises an extensible truss member, which spans the guitar body longitudinally, one end thereof lodged in a diametrically congruent depression prepared in the head block of the guitar, while the other end lodged in a similar depression prepared in the tail block thereof, whereby the head block is braced against the tail block by the spanning truss member.

5. A method of combining an acoustic guitar with a second acoustic string instrument, while preserving the distinctive tone of each instrument, comprising the steps of:
(a) providing an ordinary acoustic guitar;
(b) providing a second, ordinary acoustic string instrument having a body height comparable to or less than that of said guitar, and having an outer sidewall that is perpendicular to the soundboard of said guitar, selected from the group consisting of a banjo, a ukulele, and a mandolin;
(c) excising a section from said guitar, whose profile is delineated by an outer line segment that is contoured congruently with a shoulder and/or side edge of the soundboard, and by a complementary inner line segment that is contoured congruently with a section of said perpendicular sidewall of said second instrument that is to be embedded therein, which excision yielding a cavity that extends perpendicularly through the guitar soundboard and part-way into its body to such a variable depth that the remaining underlying rib section continuously abuts the back of the second instrument when embedded within the cavity with its soundboard coplanar with that of the guitar;
(d) fitting a sidewall segment to the cut-out edge in the soundboard and the contiguous rib edges of said guitar, and affixing it thereto;
(e) embedding said second instrument within said cut-out cavity of said guitar by affixing a section of said perpendicular sidewall thereof to said fitted sidewall segment of the guitar, so that the back of the second instrument is set in continuous abutment with the upper edge of the rib section of the guitar underlying the cut-out cavity¨the soundboards of the two instruments thus being substantially coplanar, and so that the plane of symmetry of its neck substantially parallels that of the guitar.

6. A method of combining an acoustic guitar with a second acoustic string instrument, while preserving the distinctive tone of each instrument, comprising the steps of:
(a) providing an ordinary acoustic guitar;
(b) providing a second, ordinary acoustic string instrument having a body height comparable to or less than that of said guitar, and having an outer sidewall that is perpendicular to the soundboard thereof, selected from the group consisting of a banjo, a ukulele, and a mandolin;
(c) excising a section from said guitar whose profile is delineated by an outer line segment that is contoured congruently with a shoulder and/or side edge of the soundboard of said guitar, and by a complementary inner line segment that is contoured congruently with a section of said perpendicular sidewall of said second string instrument that is to be embedded therein, which excision yielding a cavity that extends perpendicularly and coextensively throughout the guitar body;
(d) fitting a sidewall segment to the cut-out edge in the soundboard , rib and back of the guitar, and affixing it thereto;
(e) embedding said second instrument within said cut-out cavity of said guitar by affixing a section of said perpendicular sidewall thereof to said fitted sidewall segment of the guitar, so that the soundboards of the two instruments are substantially coplanar and the plane of symmetry of their necks substantially parallel.

7. The method of combining an acoustic guitar with a second acoustic string instrument defined in claim 5 or 6, further comprising the step of adapting said sidewall segment of the guitar and the section of said perpendicular sidewall of the second instrument that is affixed thereto with a plurality of registering apertures, thereby to permit acoustic communication between the two instruments.

8. The method of combining an acoustic guitar with a second acoustic string instrument defined in claim 5, 6, or 7, further comprising the step of providing an extensible truss member, and lodging a section of each end thereof within a diametrically congruent depression¨one bored in the head block of the guitar, the other in its tail block¨whereby said head block is braced against said tail block by the spanning truss member.