Note: Descriptions are shown in the official language in which they were submitted.
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DESCRIPTION
FIELD OF INVENTION
This invention is in the field of electronic transducer systems or pickups for
musical
instruments, applied specifically to acoustic and electric bowed instruments,
violins, violas and
cellos.
PRIOR ART
No prior art can be found which discloses the present invention. No patents,
no publications
and no known application discloses the method or apparatus of the present
invention.
The prior art has produced several types of effective transducer systems for
bowed/stringed
instruments, however, none of them offer a bridge replacement pickup system
using an active
hum-cancelling rotational coil transducer configuration with an on-board
active pre-
amplification circuit on a bowed instrument. All coil based transducer
pickups, hum-cancelling
or otherwise, are not used in a bridge replacement configuration on a bowed
instrument. All
other bridge replacement systems involve other transducer technologies such as
piezo
technology, and/or include components made from wood. All other transducer
pickups for
bowed instruments require a physical modification to the instrument, or in
many cases the
construction of a custom instrument in order to accommodate the design of the
transducer.
The present invention does not require any such modification(s).
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1A shows drawings of the complete, assembled pickup/bridge, covered and
uncovered and
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the battery/output module
FIG. 1B shows the complete invention mounted onto an acoustic violin
FIG. 2A shows a full assembly drawing of components to identify all parts to
be described and
their relationships to each other
FIG. 2B is a schematic drawing of the pickup apparatus
FIG. 2C shows a schematic drawing of the battery/output module
FIG. 2D shows a cross section detail of the pickup bridge, transducers,
bobbins and coils
BACKGROUND OF THE INVENTION
Violin amplification methods are known and have been heavily experimented with
by musicians
for several decades. A pickup device is a transducer that captures mechanical
vibrations from
stringed instruments such as the electric guitar or electric violin, and
converts them to an
electrical signal that is amplified, recorded, or broadcast.
For example, in the following United States of America patents:
1939: Musical Instrument - F.H. Kislingbury. (2171430)
1948: Pick Up Unit for Instruments - C. Leo Fender. (2455575)
1961: Electric Violin, and Electromagnetic Pickup Therefor - C. Leo Fender.
(3003382)
1963: Electrical stringed instrument- Ampeg Company Inc. (US3244791)
1971: Electromagnetic pickup for a stringed musical instrument - Joe D Ellis.
(US3600496)
1980: Musical instrument transducer - Fishman Lawrence R. (US4356754)
1986: For a stringed instrument having a bridge - Fishman Lawrence R.
(US4785704)
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1992: Electric Guitar/Violin - Robert Schlink. (5085115)
1996: Humbucking pickup for electric guitar. (5525750 A)
PICKUPS:
The magnetic pickup or "passive pickup" consists of a permanent magnet with a
core of
magnetic material, wrapped with a coil of several thousand turns of fine
enameled copper wire.
The humbucker is a type of pickup that uses two coils wound opposite of each
other to cancel
out the interference picked up by coil pickups.
ACTIVE PICKUPS:
Active pickups are transducer pickups that require an electrical source of
energy to operate and
include an electronic preamp circuit giving a much higher possible output.
They typically have a
wider dynamic range than passive pickups, which gives them the capability of
producing sounds
with higher fidelity and a characteristic clarity.
THE VIOLIN BRIDGE:
Typically made from maple wood, the violin bridge suspends the strings above a
bowed
instrument under great tension. Exact fitting of a violin bridge is critical
to the setup of the
instrument. A proper violin bridge establishes correct string height and
spacing for playability.
Current violin bridges are made from maple wood and are cut to fit each violin
by a luthier.
Bowed instruments form their sound at the bridge. The bridge is a conduit for
the strings'
vibration, transferring it to the body of the instrument which acts as an
acoustic sound
resonator.
OVERVIEW
This violin pickup is installed onto the instrument by removing the
traditional wooden violin
bridge and replacing it with the current invention: the pickup/bridge
assembly, which is to be
held in place by string tension alone. The Pickup can be adjusted for string
height and
playability by raising or lowering the pickup on it's base. The battery/output
module is then
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installed at the edge of the instrument near the chin rest and they are
connected with wires.
When the instrument is played, the bridge saddle vibrates rotationally under
direct contact
with the strings. Two magnetically charged steel core pieces are attracted to
the bridge and are
affected by it's vibration, causing fluctuations in their magnetic fields.
Each steel core is wound
by copper coils in a classic hum-cancelling configuration and are in place to
accept these
fluctuations and electromagnetically generate an audio signal. This signal
then passes through
an onboard pre-amplification circuit powered by a 9V DC battery power supply.
The signal then
passes through to the instrument amplifier or PA system connected to the
instrument.
All magnetic coil transducers are designed to read the changes in the magnetic
field of a
magnet as it is reacts to the string that is always suspended above it. This
pickup's design and
function differs from the traditional concept in that the magnetic field is
changed due to the
rotational movement of a metallic bridge saddle itself as vibrations are
transferred to it from
the strings through direct contact. This method becomes necessary with bowed
instruments
where the majority of vibration and sound production takes place at the
bridge, itself. The bow
generates friction causing vibrational sound, but it also mutes most of the
strings' resonance
which greatly reduces the amount of signal that is possible with suspension
(non-contact)
method pickups.
Other bridge replacement pickups for bowed instruments harness this vibration
without
modifying this relationship of 'string-to-instrument' vibrational
transmission. This bridge pickup
system is different from previous bridge replacement pickups in that it
intercepts these
vibrations, harnessing the strings' full potential on any bowed instrument,
acoustic or electric.
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DETAILED DESCRIPTION
FIG. 1A
The bowed instrument bridge pickup apparatus 1 with cover 2, the bowed
instrument pickup
apparatus uncovered with components exposed 3, and the battery/output module
4.
FIG. 18
The complete invention mounted onto a violin
FIG. 2A
The Pickup
This image shows a schematic breakdown of the pickup apparatus in orthographic
view. The
bridge 4 is formed by a strip of steel, iron, or other hard material
containing steel, with a curved
arch top 6 and a threaded non-magnetic brass shaft protruding from its bottom
5. The top edge
forms a bezier curve 6 that is characteristic of the top of a bowed
instrument's wooden bridge.
This is where the strings make contact. The threaded brass shaft extends below
to penetrate a
threaded brass nut 7, which is fixed to a brass base 8. The base is
horizontally supported by two
channels running lengthwise along each side 9. The PC circuit board carrying a
preamp SMD
circuit 10 fits between these two channels on the underside of the brass base
8 with the SMD
electronic components facing down. Sandwiched between the bridge 4 and brass
base 8 are
two transducers. Two rectangular steel blocks 12 form the center or core of
each transducer.
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Each block is housed by a polymer bobbin 11 which is rectangular in shape with
an upper plate
14 and lower plate 15 and separated at the center by a thin sleeve 16 which
tightly fits each
steel/iron block 12 and acts as a barrier between the copper coils 13 and
steel/iron block 12 to
prevent electrical shorting. Each bobbin 11 holds several thousand windings of
thin enameled
copper wire 13. One bobbin is wound clockwise, and the other bobbin is wound
counterclockwise, characteristic of a typical hum-cancelling arrangement. Both
bobbins rest
directly above a solitary polymer base 17 with two through holes 18 sized to
fit two thin
magnets 19 that exactly line up to the center of each bobbin 12. All of the
above mentioned
apparatus is secured by four mounting screws, one at each corner 20. A polymer
casing 35
snugly fits over the entire apparatus with a hole at the top of the cover to
allow the threaded
brass shaft to protrude.
The Mounting System
This apparatus is suspended above the violin by a contoured footing 21. The
footing is bezier
curved 22 to match the curvature of the violin's arched top. A threaded nut is
fixed to the top
of the curved base at the apex of the arch 23. The pickup bridge's protruding
bolt 5 engages the
threaded nut 23 and operates to finely adjust the height of the apparatus. Two
thin layers of
padding 24 are fixed to the underside of footing as a barrier against the
delicate wood surface
of a violin. This makes up the mechanism for the mounting, raising and
lowering of the
apparatus for fine adjustment in string height.
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FIG. 2C
The Battery Compartment and Output box
A two conductor shielded cable 25 is connected from the pickup's onboard
circuit 10 to an
external polymer box 26 which is sized to fit one 9V battery 31, a 1/4 inch
female output
connector 27 side by side, and a volume potentiometer 32. Both the 9V battery
compartment
opening and output jack face the same direction in the battery/output module.
Most of the
battery compartment is elevated off the surface of the violin to avoid making
contact with the
violin itself 28. A short foot extends below the module at the front edge
where it makes contact
with the violin top 29. Here, clamps commonly used for holding a violin chin
rest are used in
this design, mounted to holes in the front of the box 30. These clamps hold
the object
downwards, firmly, to the instrument's surface.
FIG. 2D
Cross Section
This to scale schematic image represents a cross section of the bridge and
coil transducers in
profile . The steel cores 12 are inserted into bobbins 11 which are wound with
fine enameled
copper wire 13. Each of the transducer coils' windings of enameled copper
wires' ends are
soldered to metal lugs 33 at the center of the device acting as electrical
terminals which extend
through the polymer base 17, brass base 8, and penetrates the PC circuit board
where contacts
are made to active circuit below. A gap 34 is left between the bobbins/cores
and the bridge
above 4. This allows for unimpeded microphonics in the transduction of the
bridge's vibrations.
