ACOUSTICAL AND PHYSICAL DYNAMICS OF THE DIATONIC HARMONICA

The harmonica is arguably the most widely played instrument in the wor ld, yet there is a surprising paucity of published studies of its acou stics or physical dynamics. The typical diatonic harmonica and the phy sical forces involved in its natural function are described, and simpl e observations of the harp's functions are reported. The speaking of t he reeds, naturally, when producing a bend, and when speaking as an ov erblow or overdraw is discussed and investigated by simple stopping of the reeds, by videostroboscopic analysis, and by recording vibration of the reeds with displacement gauges. The reeds of the ten hole harmo nica can be made to vibrate at varying frequencies depending on the si ze and shape of the player's vocal tract. Three different modes of spe aking from each hole and its pair of reeds are revealed and studied: f irst, naturally in a closing mode, either blown or drawn; second, as a bend, either blown or drawn, with pitch in the interval between the t wo notes in the hole; and third, as an overblow or overdraw in an open ing mode with a pitch outside the interval between the two natural not es of the hole. This dynamic interaction allows the player to speak wi th the instrument perhaps as with no other. (C) 1998 Acoustical Societ y of America.