Flex-a-tone for Hire
A modern instrument, the flexatone provides that "tickyticktickytockytockytockyticky" sound that has found such a good home in film music. The instrument consists of a small piece of spring steel that is fixed at one end and is encompassed by a steel outer frame. Connected to the part of the spring steel nearest the fixed end are two other strips of spring steel, one either side of the plate. On each end of the strips there is fixed a little ball of wood. If the player grasps the flexatone in one hand the thumb is naturally in the position to move the spring steel plate. If this is done while inverting the flexatone 90 degrees and moving it backwards and forwards in a sideways motion, this incredible effect can be produced. Many film and TV composers use this effect extensively as the instrument can heighten tension and is generally present just before the murderer is uncovered.
Khachaturian - Piano concerto