Methods and apparatus for vibrato effects in keyboard percussion musical instruments

#Embodiments of the present invention generally relate to keyboard percussion instruments, such as vibraphones and marimbas. In particular one or more embodiments relate to methods and apparatus to control and modulate vibrato effects in keyboard percussion instruments.

#Keyboard percussion instruments, such as vibraphones and marimbas, are musical instruments that have tone bars and are played upon by musicians with mallets. Keyboard percussion instruments of the type played on by hand-held mallets fall into two distinct categories. non-resonator instruments such as the glockenspiel (orchestra bells) and chimes (tubular bells); and resonated instruments such as the marimba, xylophone and vibraphone (“vibes”).

#Resonated instruments such as the vibraphone have resonators, usually a tube, acoustically coupled with a tone bar. The resonators of keyboard percussion instruments serve to amplify the sound of the tone bar above. Instruments of this genre that have long ringing aluminum or steel bars, such as the vibraphone and glockenspiel, often have a dampening system to allow the player to control the ring time of the bar, usually through the operation of a foot pedal. This pedal operates similarly to the sustain pedal of a piano. Pressing the pedal removes the damper bar from the keyboard; releasing the pedal allows it to return to its former dampening position, usually by means of a spring mechanism.

#FIG. 1 shows a prior art vibrato mechanism with rotating pulsar disks;

#FIGS. 2a, 2b and 2c show prior art pulsar disks in different positions;

#FIG. 3 shows a tube cover in accordance with an embodiment of the present invention;

#Before describing several exemplary embodiments of the invention, it is to be understood that the invention is not limited to the details of construction or process steps set forth in the following description. The invention is capable of other embodiments and of being practiced or being carried out in various ways.

#Embodiments of the present invention are principally illustrated by examples using keyboard percussion instruments that customarily have resonator tubes, although other instruments may also benefit from aspects of the present invention, and these benefits are fully contemplated. In accordance with one aspect of the present invention, one element of the improved keyboard percussion instrument pertains to an improved method of producing the vibrato effect. In one embodiment as shown in diagram in FIG. 3, the motorized spinning disks mounted on a shaft are replaced by one or more rectangular flat panels 501 that can cover or expose the underlying resonator, for instance tube 502 by reciprocating movement perpendicular to the plane of the length of the tube. The possible movement direction of a plate 501 is indicated by arrows 503 and 504.

#Several methods will now be provided in accordance with different aspects of the present invention. In a typical application of a keyboard percussion instrument in which there are two ranks of bars and tubes (sharps and naturals), the plates can move in parallel motion or in contrary motion. FIG. 4 diagrammatically depicts a single plate for each set of tubes. In such an arrangement, there may not be room for a sufficiently sized plate in the limited space available in the high register of commonly constructed instruments. Accordingly, in the embodiment shown in FIG. 4, the panel 601 that covers the open end 608 of resonator tubes 602 is formed with a relieved or scalloped edge 605, which fits between and under each support 610 for the tone bars 612. The direction of movement of the plate 601 is identified by arrows 603 and 604. This scalloped or relieved vibrato plate shape provides additional coverage area so that the open end of each resonator can be both fully covered and fully exposed by the reciprocating motion of a plate.