US 4,378,722 AGranted

Magnetic pickup for stringed musical instruments

OwnerDavid A. Isaksoninventor

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Abstract

An improved pickup system for stringed musical instruments, adaptable to all types of stringed instruments, in which strings pass through the hollow central portion of coils and the magnetic field within coil windings is perpendicular to the windings and parallel to the string axes. The described embodiments include an individual coil encompassing each string and a magnetic field reversed in polarity in portions of a coil oppositely disposed to a string. Magnetic elements provide an enclosed magnetic field limiting pickup response to a short, defined segment of string near an instrument's bridge. Described acoustic pickup embodiments are mounted directly to the bridge and interrupt the circle of acoustic feedback. Violin family pickup embodiments provide preferential sensing of string motions parallel to the string plane and adjustability of string response. The pickup system is designed to provide efficient and precise translation of string harmonic motions and thus reproduce the overall tonal characteristics of a stringed musical instrument.

Claims15

Dependent claims

In devices for sensing vibrational motions of tuned strings and producing thereby an electrical signal corresponding to the relative harmonic emphasis of a stringed musical instrument, a magnetic pickup comprised of:

a. coil windings of insulative conductive wire,
b. a magnetically susceptible linear string segment of each string of a musical instrument,
c. magnetic means for providing a magnetic field within each said linear string segment and portions of said coil windings,
wherein portions of a coil are disposed proximate each said linear string segment, two said portions of a coil being oppositely disposed to the axis of each said linear string segment, the axes of the coil wires in each said oppositely disposed portion of coil being substantially perpendicular to the axis of the proximate said linear string segment, said magnetic means providing a magnetic field within a portion of coil windings disposed proximate each said linear string segment, the overall north to south direction of said magnetic field within each said portion of coil windings being substantially parallel to the axis of the proximate said linear string segment and perpendicular to the axes of the coil wires in said portions of coil windings, whereby magnetic "lines of force" are disposed perpendicularly to and caused to move perpendicularly through said proximately disposed coil wires at two opposite points in each elliptical oscillation of a vibrating said linear string segment, angular motions at one said point on the ellipse causing a peak positive impulse at a coil lead while motions at the opposite point cause a peak negative impulse at the same said coil lead and the remaining composite of angular motions complete the translation of elliptical motion to a linear electrical wave form, said magnetic pickup further including means for stably positioning said coil windings and said magnetic means relative to the quiescent axes of said linear string segments of said musical instrument, and means for electrically connecting the leads of said coil windings to appropriate signal preamplification and amplification devices.

1 more element

A magnetic pickup for stringed musical instruments comprised of coil windings of insulative conductive wire and magnetic material, said magnetic material including permanent magnet material, wherein sectors of a coil of said coil windings are disposed oppositely to the axis of each string of a musical instrument and proximate a linear string segment of each said string, said linear string segments containing magnetically active material, each said coil sector being disposed between a proximate said linear string segment on one side and portions of magnetic material on an opposite side, said permanent magnet material having a north to south line of polar orientation substantially parallel to the quiescent axis of said proximate linear string segment and having reversed direction of polarity in said coil sectors which are oppositely disposed to a said linear string segment, portions of said magnetic material being also disposed proximate two end surfaces of each said disposed coil sector, each said disposed coil sector being substantially housed on three sides by magnetic material and disposed proximate a said linear string segment on a fourth side, whereby portions of said magnetic material form two confronting pairs with opposite polarity oppositely disposed proximate each said linear string segment thereby providing a magnetic field to said linear string segments and simultaneously form confronting pairs proximate each end of said oppositely disposed coil sectors thereby providing a magnetic field within said coil sectors, transverse vibrational motion of a said linear string segment in a given direction causing corresponding and simultaneous motion of said magnetic field within both said proximate coil sectors and an electrical impulse generated in one said sector is additive to the electrical impulse simultaneously generated in the oppositely disposed said sector, said magnetic pickup further including means for stably positioning said coil windings and said magnetic material relative to said linear string segments of a musical instrument, and means for electrically connecting the leads of said coil windings to appropriate signal preamplification and amplification devices.

Dependencies are inferred from the claim text.