Abstract: A variable control device accessory for a music synthesizer having a horizontally disposed keyboard. The device is positioned in front of the keyboard. It has a plurality of movable bars, at least of one of which is capable of being pivotally and slidably moved by the wrist of a player while all the others are only slidable. The bars modulate selected light beams focussed on light responsive mechanisms to produce variably dependent analog signals as inputs to the music synthesizer.

Abstract: A music synthesizer has a pivotable and slidable bar mounted in front of the keyboard of the synthesizer, the bar disposed generally parallel thereto whereby a wrist of a player may cause the bar either to pivot about an external hinge or pivot, or to slide about an axis of the bar. An actuating member is provided which responds to motion of the bar to mechanically operate potentiometers of the synthesizer to provide variably positioned dependent analog signals as inputs to the synthesizer.