US 3509264 A
Description (OCR text may contain errors)
A. J. GREEN 3,509,264
ELECTRIC DRUM OR OTHER PERCUSSION INSTRUMENT" April 28, 1970 v Filed Dec.
U Q @Q PREMIPLIFIER mvENroR Allen .1 Green BY ATTORNEY United States Patent 3,509,264 ELECTRIC DRUM OR OTHER PERCUSSION INSTRUMENT Allen J. Green, 1514 44th St., Brooklyn, N.Y. 11219 Filed Dec. 29, 1967, Ser. No. 694,451 Int. Cl. Gh 3/00, 1/00; G10d 13/02 U.S. Cl. 84-1.15 10 Claims ABSTRACT OF THE DISCLOSURE The electric pickup for the instrument has two relatively movable parts, a coil and a magnet. One part is secured by epoxy cement to, and vibrates with, a vibratory member such as the skin of a drum or the disc of a cymbal. The other part is secured to a relatively fixed element of the instrument. In use, the weak signal induced in the coil is led to a preamplifier and amplified.
This invention relates to the means foramplifying the sounds of certain musical instruments such as drums, cymbals, gongs, bells and other percussion instruments.
The noise resulting from mechanical impact of the striking element upon the vibratory element of the instrument would, especially if amplified, in many instances interfere with the sound produced by the mere vibration of the vibratory element such as a drum skin, a cymbal disc or gong disc, or the campanulate element .of a bell. The frequency of the desired sound waves to be produced by the instrument may also be altered or distorted. Furthermore, the force of such impact, as well as the vibration of the instrument, tend to loosen and ultimately detach any pickup part attached by any means to the vibratory element.
It has been found, that any pickup part applied to a drum skin should have minimum weight and should be so attached that loosening and detachment thereof under the forces of use, does not occur. The pickup should also screen out mechanical noises but should faithfully reproduce and amplify the pure tone of the vibratory element. The output signal of the pickup may-properly be quite weak, since known preamplifiers to which the signal may be led, usually accept a low impedance input.
The pickup of the present invention meets all the requirements above outlined and in addition has few parts, is simple, inexpensive, not likely to get out of order, and easily attached to percussion instruments of various types.
The various objects of the invention will be clear from the above and from the description which follows and from the drawings, in which- FIG. 1 is a top plan of one type of a conventional drum to which the invention has been applied, part of the drum skin being omitted to reveal the underlying parts.
FIG. 2 is a fragmentary elevational view of the drum partly in section and showing the connection to a pre* amplifier.
FIG. 3 is an enlarged fragmentary vertical sectional view of the drum and pickup therefor, the arrows showing the general direction of the vibratory movement of the drum skin.
FIG. 4 is a partial verticalsectional view of a loosely mounted cymbal, showing a modified form of the pickup.
FIG. 5 is a similar fragmentary view of a firmly mounted cymbal and pickup therefor.
In general, the pickup converts the percussion instrument to a sound amplifying device akin to a microphone, thereby permitting direct amplification for recording purposes or for the entertainment of large audiences without the need for external microphones and relatively expensive pickup installations. The pickup comprises magnet P 64 Ice 3,509 2 means preferably in the form of a permanent magnet and coil means of various possible forms and arrangements but secured firmly, one of the means to a vibratory element of the instrument and the other means to a fixed part. The coil means is arranged in inductive relation to the magnet means and in sufficient spaced relation thereto toprevent contact thereof in use when the vibratory element is struck with the maximum force customarily used when playing the instrument. Similarly, since the coil means preferably has a ferric core and would be attracted by and retained by the magnet means against retraction to the proper operative position of the coil means, the spacing between the two means and the strength of the magnet means should be such as to avoid such retention.
In the practical embodiment of the invention shown in FIGS. 1-3, the drum 10 may vary greatly in type and in size, but the same pickup 11 may be used despite such variations. To the tightened drum skin 12, which conventionally constitutes the vibratory element of the drum, is suitably secured the coil 13, the skin being of suflicient area and wide enough to permit such attachment. It will beunderstood however, that in the case of other percussion instruments having vibratory elements of substantial width, rigidity and strength, the relatively heavy magnetic means of the pickup instead of the coil means may be fixed to the vibratory element in such a manner as .to vibrate as a unit therewith, as in FIGS. 4 and 5 wherein the magnet is affixed to the cymbal disc.
For the purpose of illustration, the drum skin 12 has been shown as clamped to the drumside or cylinder by means of a clamping ring 14, but it should be understood that the construction of the drum is of no significance in the operation of the pickup, provided that'the drum hasa vibratory element and a relatively fixed element as in most percussion instruments.
To construct a coil structure substantially impervious to mechanical shock resulting from use of the instrument, fine enamelled wire is preferably wound in a number of layers, such as three, around a ferriccore 16. Strip material of rectangular cross section, and known as transformer leaf, has been found satisfactory for the core. Between the layers of wire turns is interposed a layer of suitable dielectric or insulating strong plastic cementsuch as epoxy resinous cement or adhesive which bonds the core, the turns and layers of wire together against possible dislocation and unwinding under the stresses resulting from percussion. The plastic quick setting epoxy resin and hardener sold under the trademark Duro by The Woodhill Chemical Corporation of Cleveland, Ohio, has been found to be adequate for the purpose. The same epoxy plastic cement is preferably used for encapsulation not only of the coil and its core to fill all interstices and spaces therein but also for encapsulation of the coil leads to the shielded cable 17 which connect the coil to a suitable pin plug receptacle 18. Said receptacle is fixed to the drum side in any suitable manner and conductors extend therefrom to a preamplifier 19.
As has been indicated, it is highly advisable in View of the severe mechanical forces inherent in the operation of the drum and which tend to loosen the coil, that suitable means be employed to affix and strongly hold the coil to the drum skin. Such means should also result in a rigid attachment of the coil in a manner to transmit faithfully the sound vibrations of the skin to the coil without being so excessively thick as to distort the drum tones or to transmit unwanted sounds such as the sound of impact of the striker such as a drum stick, upon theskin. By bending the core member 16 into an L-shaped form, the flange or leg 20* thereof outstanding from the core proper of the coil, becomes an attaching bracket member and may readily be secured to the under face of the drum skin Patented Apr. 28, 1970' by means of a patch 21 of substantial area of epoxy cement of the type above mentioned and approximately inch thick thereby to suspend the coil from the skin. The patch extends past the leg 20 on both sides and covers an area of about one inch square as best seen in FIG. 1.
The magnet 22 constitutes the remainder of the pickup and is secured to a relatively fixed part of the drum such as the drum side 23, against which the skin is clamped. While any suitable means may be employed to fix the magnet in place, a layer 24 of the epoxy cement mentioned above is preferred. The gap between the pole of the magnet and the coil 13 is preferably about inch for small drums. It will be understood that said gap lessens when the skin is depressed by a blow, and that the coil consequently swings somewhat closer to the magnet at that time, but not enough to be drawn into contact with the magnet and to stick thereto against retraction on the return of the skin to its normal position. As seen in FIG. 3, the skin vibrates vertically when struck, so that the coil vibrates therewith and with its core 16 as a unit and in the plane of said core and in the magnetic field to induce the desired signal.
In the form of the invention shown in FIG. 4, the cymbal disc 25 is provided with a central aperture 26 larger in diameter than that of the reduced extension 27 passing through the aperture and projecting from the end portion of the relatively fixed disc-supporting rod 28. The disc normally rests on the shoulder 29 loosely at the junction of the extension 27 with the remainder of the support rod. The nut 30 on the extension adjustably limits the upward movement of the disc under impact. As shown, the coil 31 is fixedly mounted on the upper part of the rod 28 in the field of the annular magnet 32, said rod constituting the core of the coil and being integrated with the disc support. Any suitable means may secure the magnet to the disc 25 concentrically of the coil 31, but as shown, a layer 33 of epoxy cement is used for that purpose. The magnet therefore vibrates with the disc as a unit and relatively to the core 28 to induce the required signal.
In FIG. 5, a central aperture in the disc is of about the diameter of the threaded extension 27, and the nut 30 holds the cymbal disc firmly against the shoulder 29. Obviously, the pickup may be applied to cymbals of various constructions, as well as to other percussion instruments, so long as the general principles of the invention are followed. The magnet may be attached to a relatively fixed part of the instrument or to the wide vibratory part, while the coil is attached to the other of the two parts and in the magnetic field, care being taken to so arrange the coil and the magnet that a sufliciently large gap is provided between the coil and the magnet ,and that the attachment thereof, by whatever means, though preferably by epoxy resin, is strong and durable.
While certain specific forms of the invention have herein been shown and described, various obvious changes may be made therein and which need not be detailed, without departing from the spirit of the invention defined by the appended claims.
1. The combination with a percussion musical instrument such as a drum, cymbal, gong, bell or the like, said instrument being provided with a relatively wide vibratory percussion element adapted to be struck directly and repeatedly with a striker and with a fixed element fixed relatively to the percussion element, of
a pickup for the instrument adapted effectively to resist damage and displacement under the blows of said striker, said pickup comprising magnet means fixed to one of said elements, and coil means having a winding and a metallic core bonded to said winding, said coil means being fixed to the other of said elements in inductive relation to the magnet means, whereby on movement of one of said means relatively to the other when the percussion element is struck, an electric signal is generated in the coil means.
2. The combination of claim 1, the magnet means being completely outside of the coil means and in sufficient spaced relation thereto to prevent mutual contact thereof in use and also to prevent magnetic retention of the coil means by the magnet means on maximum movement of the percussion element under a severe blow and consequent substantial relative movement of the coil means and the magnet means toward each other.
3. The combination of claim 1, a layer of epoxy cement interposed between and firmly securing one of said means to the inner surface of the percussion element and encapsulation of epoxy cement completely encasing the coil means including said core, the core passing completely through the winding.
4. The combination of claim 1, the magnet means being a permanent magnet, the core of the coil means being an L-shaped strip, one leg of the core carrying the winding, the other leg being bare and encapsulated in epoxy cement and secured thereby to the inner surface of the percussion element.
5. The combination of claim 1, the instrument being a cymbal including a cymbal disc, one of said means being annular and secured to the inner face of the disc and surrounding the other of said means, the other of said means being secured to the fixed element concentrically of the annular means.
6. The combination of claim 1, the instrument being a drum, the magnet means being a permanent magnet arranged completely outside of the coil means, the percussion element being the skin of the drum, the entire coil means including said core being affixed directly to the inner face of the skin by a layer of epoxy cement approximately inch thick, the coil means being encapsulated in epoxy cement to fill all spaces therein and being movable as a unit with the skin relatively to the magnet when the skin is struck.
7. The combination of claim 4, the winding and the core of the coil means being encapsulated in epoxy cement, and the bare leg of the core supporting said coil means in substantial spaced relation to and beyond the magnet.
8. The combination of claim 1, the instrument being a drum, the percussion element being the skin of the drum, the magnet means being a permanent magnet, the coil means having an L-shaped ferric core, one leg of the core carrying the coil the other leg being bare and encapsulated in adhesive means and secured thereby to the inner surface of the skin between the center of the skin and the side of the drum in sulficient spaced relation to the coil means to prevent magnetic retention of the coil means in use of the drum, the thickness of the adhesive means for the bare leg of the core being insufiicient to interfere with the vibration of the skin.
9. The combination of claim 5, said one of said means being the magnet means, and the other of said means being the coil means, the fixed element constituting a support for the disc and also the core of the coil means.
10. For use in a percussion musical instrument provided with a vibratory percussion element of substantial length, width and area having a surface exposed to a forcible blow by a striker and also having a relatively fixed supporting element for the percussion element,
a pickup comprising a coil encapsulated in epoxy cement and having a combined metallic core and support for the coil bonded thereto, said core passing completely through the coil and being adapted for integration with a selected one of said elements to affix the coil directly to said element, and a magnet completely outside of and in sufiicient spaced relation to the coil and the core to prevent magnetic retention of the coil by said 6 magnet, said magnet being adapted to be 86- 2,988,946 6/1961 Ritchie 841.15 cured to the other of said elements by epoxy 3,018,680 1/1962 Paul 841.15 X
HERMAN KARL SAALBACH, Primary Examiner References Cited 5 T. J. VEZEAU, Assistant Examiner UNITED STATES PATENTS 2,900,453 8/1959 Cammack s4- 411x 2,938,420 5/1960 Kunz s4 1.15 s4 1.01, 411, 462