[0001] This invention relates to an improved electric guitar and is more especially directed
at providing an electric guitar which can optionally be used as an acoustic or amplified
acoustic guitar.
[0002] Traditionally for proper operation of an electric guitar, especially at high volumes,
the electric guitar has been constructed with a solid body to which electromagnetic
pickups have been mounted for sensing vibrations of the strings to produce a signal
which can be amplified as the instrument output. While very popular and of considerable
use for certain of the more popular types of modern music, such guitars cannot produce
any substantial degree of audible sound if used without the electrical pickup and
amplification and also do not provide the tone and musical qualities required of a
conventional acoustic guitar which is used for playing more traditional and classical
types of guitar music. Attempts have been made to amplify the music obtained from
acoustic guitars, which have a thin-walled hollow body, by mounting. a transducer
to the face or some other portion of the body in order to sense vibrations of that
body portion and produce an electric signal which can be amplified. However, this
solution is by no means fully satisfactory in that feedback and other problems can
arise, especially when a substantial degree of amplification is being used, causing
a distortion of the output.
[0003] The present invention is directed at providing a guitar which has the more beneficial
characteristics of both the amplified acoustic and conventional electric guitars and
yet which can also be used without any electrical amplification whatsoever to produce
a direct sound of good quality when the player requires, as for example when playing
in a confined space or when practising.
[0004] According to the present invention there is provided an electric guitar comprising
a hollow body with a neck rigidly attached thereto for tensioning strings attached
to a bridge carried on the front face of the body, said body comprising a rigid back
and sides defining the rear and sides of an internal cavity and a flexible front table
covering the cavity and to which the bridge is secured, an aperture being provided
through said table with an electric pickup securely mounted to the rigid back of the
body within the cavity projecting through the aperture to a location for cooperation
with the guitar strings. Preferably, one pickup, the lead pickup, is provided closely
adjacent the bridge with a second, rhythm, pickup being provided between the first
pickup and the neck. Preferably the second pickup can be provided projecting from
a portion of the table rigidly secured to the metal of the body so that the vibrating
part of the table which is used when the guitar is in its acoustic mode is that portion
of the table which covers a cavity through which is rigidly secured the first, lead,
pickup to project through the aperture in the table. A transducer for allowing the
guitar to be used to provide an output similar to that of an amplified acoustic guitar
can be secured to the undersurface of the flexible table within the cavity in the
body. As well as conventional controls for controlling the volume and tone of the
lead and rhythm pickups an additional switch may be provided on the front of the guitar
for controlling whether the guitar is being used in its electric or amplified acoustic
mode.
[0005] In order to obtain proper vibration of the table over the cavity to provide good
acoustic properties to the guitar when used in its acoustic mode, it is desirable
that the cover be made of a fairly resilient material, for example spruce, and also
be provided with suitable stiffening on its rear side by a system of spaced bracing.
The bridge can then be relatively massive, being secured through the table to the
bracing, with the result that the strings of the instrument are adequately supported
for use in electric mode and provide a good quality sound vibration to the vibrating
table in the acoustic mode of the guitar,
[0006] The invention will be further described, by way of example, with reference to the
accompanying drawings, in which:
Figure 1 is a plan view of a guitar embodying the invention;
Figure 2 is a diagrammatic plan view of the instrument with the top or table removed
showing the internal cavity;
Figure 3 is a diagrammatic side elevation view of the guitar with the stringing and
bridge omitted; and
Figure 4 is a view of the table from below.
[0007] Referring to the drawings, in Fig. 1 there is shown a guitar having a body from which
projects a neck 11 provided with the usual peg head 10. Strings are tensioned from
the peg head over a fret board on the neck 11 to a bridge 16 mounted on the front
table 23 of the guitar body. Projecting from the guitar body are a rhythm pickup 12
and a lead pickup 13 for sensing vibrations of the strings when the guitar is being
used in its electric mode. Also mounted on the front table 23 of the guitar are the
various controls illustrated as a three position pickup selector switch 17 for use
when the guitar is in its electric mode, the switch being movable between three positions
in which either the lead pickup 13 only, both pickups or the rhythm pickup 12 only
are in operation. A second switch 14 is actuatable between positions to control whether
the guitar is in its electric or its amplified acoustic mode.
[0008] Knobs 19 and 21 are volume control knobs operable respectively when the guitar is
in its amplified acoustic and electric modes. The knob 18 is a tone control for the
rhythm pickup and it also has a push-pull switch to control a conventional variable
coil tap arrangement for the rhythm pickup. The knob 20 serves a similar function
for controlling operation of the lead pickup.
[0009] While these particular control arrangements have been indicated it will be appreciated
that these may be varied as convenient, for example a common volume control could
be used for both the amplified acoustic and the electric modes.
[0010] As should be appreciated from Fig. 2, the body of the guitar has a substantially
rigid and massive back and sides 32 surrounding an internal cavity 24. These portions
of the body are sufficiently solid and rigid to act in a similar manner to the rigid
body of a conventional electric guitar. Provided in the cavity 24 a mounting block
25 is shown rigidly attached to the back of the guitar while the body is also shown
as comprising a recess 33 for receipt of the rhythm pickup. An acoustic pre-amplifier
31 is shown mounted in the cavity secured to the rigid side wall thereof.
[0011] The general internal arrangement of the guitar body can be appreciated from Fig.
3, where the cavity 24 with the mounting block 25 is visible with the lead pickup
13 projecting through an aperture 15 in the table 23. The rhythm pickup 12 is mounted
in the aperture 33 in the body to project through an aperture 28 in the front or table
23. It will thus be appreciated that the rhythm pickup 12 projects from a rigidly
supported, non-vibrating, portion of the table 23.
[0012] In order to provide good sound qualities to the vibrating portion of the table 23
covering the cavity 24, a preferred material for the table is spruce. In order to
obtain good acoustic properties it is preferred for the bridge 16 to be made fairly
massively of solid metal and secured in position by bolts 28 which pass through the
table 23 and engage a main piece 27 of bracing secured to the underneath of the table
23 within the cavity 24 as shown in Fig. 4. Radiating outwardly from the main piece
27 of the bracing towards the side wall 32 of the body are arms 26. Also secured to
the underside of the table 23 is a transducer 30 which is activated when the guitar
is used in its amplified acoustic mode.
[0013] Generally, with the construction as shown, it has been found that the electric guitar
is of sufficiently rigid construction to operate successfully as a conventional electric
guitar and yet it can be simply switched so as to deactivate both the pickups and
activate the transducer 30 and then be used to provide an output at least comparable
with that obtained from an amplified acoustic guitar. With no electric amplification
at all a substantial and adequate volume output can still be obtained simply in a
normal acoustic mode using the cavity 24 as a sound box with the vibrating carefully
braced table 23 of flexible wood thereabove.
[0014] While for normal high quality purposes it will be expected that the body of the guitar
will be made principally of wood, other materials, for example reinforced plastics,
may be used with appropriate design changes from the construction exemplified in the
drawings.
[0015] Also, while a fret board has been referred to above it is preferred that, instead,
a pitchboard as described in British patent specification no. 1511840 be used.
1. An electric guitar comprising a hollow body with a neck 11 rigidly projecting therefrom
carrying means for tensioning strings attached to a bridge (16) carried on the front
face of the body, characterised in that said body comprises a rigid back and sides
(32) defining the rear and sides of an internal cavity (24) and a flexible front table
(23) covering the cavity and to which the bridge is secured, an aperture (15) being
provided through said table with an electric pickup (13) securely mounted (at 25)
to the rigid back of the body within the cavity (24) projecting through the aperture
to a location for cooperation with the guitar strings.
2. An electric guitar according to claim 1, characterised in that the pickup (13)
is closely adjacent the bridge (16).
3. An electric guitar according to claim 1 or 2, characterised in that a second pickup
(12) is provided projecting from a portion of the table (13) rigidly secured to the
back (32) of the body at a location (33) between the first pickup (13) and the neck
(11).
4. An electric guitar according to any preceding claim, characterised in that a transducer
(30) is secured to the flexible table (23) whereby the guitar may be used as an amplified
acoustic guitar.
5. An electric guitar according to any preceding claim, characterised in that the
underside of the table (23) within the cavity (24) has bracing (26,27) secured thereto
to stiffen the table.
6. An electric guitar according to claim 5, characterised in that the bridge (16)
is substantially massive and secured through the table (13) to said bracing (26,27).
7. An electric guitar according to claim 6, characterised in that the bracing comprises
a main piece (27) beneath the bridge (16) and to which the bridge is attached and
arms (26) radiating from the main piece (27) towards the side wall of the guitar body.
8. An electric guitar according to any preceding claim, characterised in that a switch
(14) is provided for selective operation of the guitar as an electric guitar or as
an amplified acoustic guitar.
9. An electric guitar according to claim 8, characterised in that the switch (14)
is provided on the front table (23) together with a switch (17) for selecting either
one or both of separate lead and rhythm pickups (12,13), means (19,21) for controlling
the output volume and means (18,20) for controlling the tone from the pickups.