Electronic Drum With Vibration Isolating Head

The present invention relates to an electronic drum.

In a conventional electronic drum, a drum head or a pad is struck by a stick, and a vibration caused thereby is converted into an electrical signal. A musical tone (electronic tone) generating operation of an electronic tone source apparatus (such as a PCM tone source or an FM tone source) is controlled by waveform information of the electrical signal (striking position as a function of time, tone volume, and the like), thereby generating an electronic tone from a loudspeaker. In particular, the electronic drum must satisfy the following requirements: even if any portion of the drum head or pad is struck, the output (i.e., sensitivity) from a pickup device must be uniform; a change in signal in accordance with a change in striking force coincides with feeling of a performer; and a stick feeling must resemble that of an acoustic drum. Therefore, the material of the drum head and its mounting structure determine the performance of the electronic drum. Various drum heads have beer proposed, and for example, Japanese Utility Model Publication No. 59-39753, Japanese Utility Model Laid-Open Nos. 55-97792 and 58-113070 are known.

However, in an electronic percussion disclosed in Japanese Utility Model Publication No. 59-39753, outer peripheral portions of two vibration films are bonded to each other, and a cushion member and a pickup device are arranged between the vibration films to constitute a drum head. Therefore, a means for supporting and tensing the drum head is necessary as in an acoustic drum, resulting in a complicated structure and poor handling. In addition, sensitivity variation occurs depending on striking positions. In an electronic percussion disclosed in Japanese Utility Model Laid-Open No. 55-97792, a reception member is disposed in an opening of a cylindrical body, a cushion material is placed on the reception member, and the cushion material is covered with a striking film. However, with this electronic percussion, the striking film must be supported and tensed at a predetermined tensile force. Therefore, the structure is complicated, and sensitivity variation occurs as in the above mentioned electronic percussion.

In a snare drum trainer disclosed in Japanese Utility Model Laid-Open No. 58-113070, a foamed member is disposed on the surface of a base, and a dummy head is adhered thereon. With this structure, although good stick feeling can be obtained, it is nothing but a trainer, and cannot be satisfactorily used for performance.

As another conventional apparatus, the following electronic drum is known. More specifically, as shown in FIG. 4, a drum head 1 is tensed on a cylindrical body 2 by a known support/tension means 3, and a cushion member 5 is arranged between the drum head 1 and an intermediate plate 4. A dynamic loudspeaker 6 as a microphone is mounted on the lower surface of the intermediate plate 4. With this electronic drum, stick feeling can resemble that of the acoustic drum. However, since the electronic drum of this type has poor high-frequency characteristics, a delicate stick work cannot be easily detected. In addition, since the loudspeaker 6 has a large thickness, the thickness of the drum is inevitably increased. It is therefore difficult to realize a low-profile electronic drum.

It is an object of the present invention to provide an electronic drum which has a simple structure, and can eliminate a sensitivity variation depending on striking positions, and has good stick feeling.

In order to achieve the above object, there is provided an electronic drum comprising: a head portion to be struck by a performer; an annular frame arranged to generally surround the head portion; a vibration plate, arranged to be in tight contact with a lower surface of the head portion, for vibrating in response to the performer's strike of the head portion; a pickup device, mounted on the vibration plate, for detecting the vibration of the vibration plate; vibration preventing means, inserted between the head portion and the annular frame, for preventing the vibration from being transmitted to the annular frame, wherein the head portion and the vibration preventing means are integrally formed of a flexible material; and a sound device connected to the pickup device for sounding in response to the detected vibration.

FIG. 1 is a longitudinal sectional view showing an electronic drum according to an embodiment of the present invention;

FIG. 2 is a partially cutaway plan view of the electronic drum shown in FIG. 1;

FIG. 3 is a partial sectional view of an electronic drum according to a modification of the embodiment shown in FIG. 1; and

FIG. 4 is a sectional view showing a conventional electronic drum.

An embodiment of the present invention will now be described with reference to the accompanying drawings.

FIGS. 1 and 2 show an electronic drum according to an embodiment of the present invention. Referring to FIGS. 1 and 2, an electronic drum 10 comprises a substantially circular instrument case 11 with a shallow bottom. The case 11 has an upper opening. The instrument case 11 is formed of a plastic or metal plate. A portion the periphery of the case 11 projects in the radial direction in a substantially trapezoidal shape, thus constituting a mounting portion 13 for an instrument support rod 12 of an instrument stand (not shown). The rod 12 normally has a polygonal shape, and facilitates fixing by a bolt (to be described later). A metal holder 14 for fixing the electronic drum 10 to the rod 12 is arranged and fixed inside the mounting portion 13. The holder 14 has a rod insertion hole 15 receiving the rod 12, and a tightening bolt 16 for pressing the rod 12 against the inner surface of the insertion hole 15 and fixing it. A hole 17 is formed in the mounting portion 13 in correspondence with the rod insertion hole 15. Note that a nut is threadably engaged with and fixed to the distal end of the bolt 16, and that the outer surface of the nut is covered with a washer which is partially fixed to the holder 14, so that the rod 12 is fixed by the bolt 16 through the washer.

A substantially annular frame 20 of a metal such as aluminum which is cut and open at the mounting portion 13 is fitted in the inner surface of the upper opening of the instrument case 11 and is fixed thereto by a plurality of set screws 21. The holder 14 is fixed to the inner surface of the open end portion of the annular frame 20 by a plurality of set screws 22. A pad cover 25 formed of a flexible material such as rubber is covered on the upper opening portion of the instrument case 11, and covers the opening portion and the holder 14. A fitting holder 27 having a substantially inverted U shape is integrally formed on the peripheral portion of the pad cover 25, and is fitted on the end of opening of the instrument case 11 and the annular frame 20 from the above. A vibration plate 29 has a smaller diameter than an inner diameter of the annular frame 20 and a proper thickness and is formed of a synthetic resin, wood, or the like. The vibration plate 29 is fixed to the inner surface of a head portion 28 which is struck by a stick. The head portion 28 in tight contact with the vibration plate 29 has a thin boundary portion or vibration preventing portion 25a on its peripheral portion so as to prevent transmission of its vibration to the surrounding portion when it is struck and so as to be supported by the surrounding portion. Therefore, the head portion 28 is spatially separated from other portions and hence, has a floating structure. A bolt insertion hole 30 through which the tightening bolt 16 extends is formed in the head portion 28 in correspondence with the tightening bolt 16 for the pad cover 25. A first pickup device 33 for picking up the vibration of the vibration plate 29 and converting it into an electrical signal is fixed to a proper portion of the lower surface of the vibration plate 29. A lead wire 34 of the pickup device 33 is connected to a jack 35 extending through the wall of the instrument case 11. The jack 35 is connected to a sound means through wires. The sound means produces a drum sound when the head portion 28 is struck by the stick.

A second pickup device 36 is mounted on the lower surface of the holder 14 through a cushion 37. The second pickup device 36 is arranged to detect a vibration of the holder 14 upon a rim shot, and is connected to another jack (not shown) by a lead wire 38. In this case, the second pickup device 36 need not always be mounted on the holder 14 but may be fixed to the inner surface of the instrument case 11 through the cushion 37 to detect the vibration of the case 11 upon a rim shot.

In the electronic drum 10 with the above structure, the head portion 28 of the pad cover 25 has the complete floating structure, and is vibrated together with the vibration plate 29 upon striking. Since the head portion 28 is coupled to the surrounding portion other than the head portion 28 through only the vibration preventing portion 25a, the striking vibration is satisfactorily transmitted to the entire vibration plate 29 in tight contact with the head portion 28 and is averaged. Therefore, the vibration preventing portion 25a can cause the head portion 28 to be spatially separated from the surrounding portion, and hence, can prevent a striking vibration from being transmitted to an external portion from the vibration preventing portion 25a. Since the floating structure is adopted, a stick feeling resembling striking of a drum head of an acoustic drum can be obtained. In addition, when the peripheral edge portion of the pad cover 25, i.e., the fitting holder 27 is struck, the vibration caused thereby is transmitted to the cushion member 37 through the instrument case 11 and the holder 14, and is detected by the second pickup device 36. The detected vibration is converted into an electrical signal, and can be positively produced as a rim shot tone.

In the case of a drum, a plurality of pads are often used. When the head portion 28 of the pad cover 25 adopts the floating structure, if one pad is struck, other pads are not influenced thereby, and tone separation can be improved.

The present invention is not limited to the above embodiment, and various applications and modifications may be made within spirit of the invention. FIG. 3 shows a modification of the present invention. The same reference numerals in this modification denote the parts having the same functions as in FIG. 1. Referring to FIG. 3, a large number of recesses 40 are formed along the circumferential direction of a peripheral edge portion 27a of the pad cover 25 placed on the annular frame 20. With these recesses 40, the contacting area between the peripheral edge portion 27a and the annular frame 20 is reduced, so that a performer can obtain a soft rim-shot touch, thereby improving the stick feeling. Head portion 28 may also include annular rib 28a at its outer periphery.

As described above, in the electronic drum of the present invention, an upper opening of the instrument case is covered by a pad cover of a flexible material, the head portion of the cover has a floating structure, and a vibration plate having a pickup device is mounted on the lower surface of the head portion. Therefore, a striking vibration transmitted to the vibration plate through the pad cover can be averaged by the vibration of the head portion, and a sensitivity variation depending on the striking positions can be eliminated and prevented. In addition, a stick feeling can be controlled by changing the thickness and hardness of the pad cover or the hardness of the vibration plate.