Acoustic coupling between oral tract and diatonic harmonica: Recent observations

The diatonic harmonica is arguably one of the most ‘‘vocal’’ of all reed instruments. Due to the relatively short distance, thus tight coupling, between the player’s oral cavity and the instrument, relatively subtle changes in the oral tract may effect dramatic modulations of both frequency and spectral content of the sound produced. Over the past several years we have endeavored to improve the understanding of this interaction, as well as the coupling between reeds of a given cell. This presentation will discuss our most recent observations. Benchtop experiments were conducted by laser vibrometer to measure the simultaneous motion of the reeds. Studies on human subjects were based on x‐ray, ultrasonographic, and laryngoscopic imaging of players while sounding notes on the harmonica. Evidence of torsional instability has been observed, and analyzed by subsequent computational fluid dynamics simulation.