Abstract: A make-break contact assembly useful in the art of musical education comprises switch means and is mounted upon expandible strap means intended to encircle the head of a student to pass adjacent to the chin area and lower jaw and to be responsive to jaw movements to expand or contract the strap means to precipitate the make contact and break contact electrical states of the contact assembly, respectively, selectively indicative of a proper jaw position resulting in proper mouth-playing orientation or an improper jaw position resulting in improper mouth-playing orientation, and visual signalling differentiating between proper and improper jaw positions.