1. A KEYBOARD KEY TRANSDUCER ASSEMBLY COMPRISING A MANUALLY OPERATED KEY ELEMENT ADAPTED TO BE RECEIVED BY A KEYBOARD, A SUBSTANTIALLY FLAT CRYSTAL SECTION HAVING A PORTION THEREOF HELD RIGID TO FORM A CANTILEVER CONDUCTING MEANS COUPLED TO OPPOSITE SIDES OF SAID CRYSTAL, MECHANICAL STRIKING MEANS COUPLED TO SAID MANUALLY OPERATED KEY ELEMENT FOR TRANSMITTING A TRANSIENT FORCE TO AN EXPOSED SURFACE OF SAID CRYSTAL IN RESPONSE TO OPERATION OF SAID KEY ELEMENT IN ORDER TO PRODUCE A VOLTAGE PULSE ACROSS SAID ELECTRICAL CONDUCTING MEANS.