AUDIO-VISUAL TEACHING DEVICE AND METHOD FOR INSTRUCTION IN THE OPERATION OF KEYBOARD CONTROLLED INSTRUMENTS

摘要

An apparatus for teaching the operation of a keyboard instrument comprises audio and visual components actuated respectively by voice signals and cueing signals both recorded at audio frequencies on a single "track" of magnetic medium. The cueing signals are superimposed on an audio inhibit signal of a preselected frequency which may or may not be within audio range and which is effective through a filter network to switch the apparatus from an audio mode to a visual mode in advance of the cueing signals and to maintain the apparatus in the visual mode during decoding of the cueing signals. Alternatively, cueing signals of brief duration are used to trigger a latching circuit to hold a visual indicator activated while further audio instructions are reproduced, and a subsequent cueing signal serves to unlatch the circuit to terminate the visual indication.