| Popis: |
The acoustical properties of the ancient Carnatic drum, the mridangam, have been studied, including instruments of traditional design as well as instruments with a newly designed mounting method for the drumheads. The mridangam is comprised of three primary parts: The tonal head (valanthalai), the bass head (thoppi), and the central shell (katta), to which the two heads are traditionally fastened by leather rope. The new design is proposed as a convenient and practical way to mount and tune the drumheads. Measurements were made on drums with the drumheads mounted in the traditional way, and then repeated with the heads remounted using the new design. For measurements of the modes and mode frequencies of the drumheads, the modes were excited by a mechanical vibrator and vibration of the drumhead was measured using a laser vibrometer system. The frequencies of the first few modes of the tonal head were found, as expected, to be tuned to be approximately harmonic. Measurements of drumhead vibration and sound spectra were also made when the drumhead was excited by a skilled player using standard strokes. Some effects of coupling between the two drumheads were studied. [Work supported by the Kalamazoo College HHMI Undergraduate Research Program.] |
