Free aerophone
DEFINITION
An instrument classified as an aerophone and produces sound by freely using air as the primary vibrating means. As opposed to a normal aerophone where typically the performer's breath provides the air source as a column, free aerophones such as the bull-roarer, set the air into vibration by simply spinning the instrument through the air. Thus, in free aerophones, the air is not confined to the instrument or to an air column within the instrument.See Accordion, Harmonica, Harmonium, Sheng.