Speaker
Description
The Dan Bau (in Vietnamese: Đàn Bầu) is a Vietnamese monochord zither that is played by exciting the harmonics of the string by 1) dampening the string at a position of an antinode with the ulnar side of the palm, followed by 2) plucking the string in an upwards motion with a long plectrum while 3) releasing the dampening. Changing the tension of the string by inflecting the bending rod on which the string is mounted allows the Dan Bau performer to play pitches outside the harmonic series of the string and to add ornamentation. We investigated the relationship between the force applied to the bending rod, its horizontal displacement and the resulting pitch. To this end, we used a manual XY translation stage to inflect the bending rod. A load cell mounted on the translation stage measured the force applied to it. We recorded the sound of the Đàn Bầu after bending it in 5 mm steps in both directions along its axis. Excitation is accomplished using a pluck mounted on a linear guide. We found that the force needed to alter the pitch varies with the bending direction. Due to physical constraints, a player would need less force to decrease the pitch by a certain interval than to increase the pitch, which introduces an asymmetry in playing technique with the bending rod. These results may inform the development of new digital musical instruments that borrow from the gestural repertoire of the Dan Bau.