Junehee Yoo

Publication Date

2005

Document Type

Dissertation/Thesis

First Advisor

Rossing, Thomas D., 1929-

Degree Name

Ph.D. (Doctor of Philosophy)

Legacy Department

Department of Physics

LCSH

Percussion instruments--Korea--Acoustics

Abstract

The pyeongyeong and the pyeonjong have long been cherished as standard instruments in Korean court music. Pyeongyeong is a set of sixteen L-shaped chime stones and pyeonjong is a set of sixteen oval chime bells. To figure out the acoustical properties of the pyeongyeong and the pyeonjong, the vibrational modes are obtained by using FFT analyzers, accelerometer scanning, TV holography, and impact hammer testing. Especially to test the geometry effects on the tuning, the finite element method is introduced. The pyeongyeong covers one and one third octave from 528.6 Hz to 1262.8 Hz. The nominal frequency of the first stone, whangjong, is 528.6 Hz which is 17.6 cents higher than 523.25 Hz, the frequency of the C5 note in the A440 tempered scale. The second mode is tuned to about 1.5 times the nominal frequency, which means the second partial is tuned to be a perfect fifth above the nominal. The third mode is tuned to about 2.3 times the nominal frequency. Mode shapes of a gyeong from three different methods agree with each other. In most cases, the modes seem to be combinations of bending and torsional motion. The calculated results by using the finite element method show that the ratio frequencies of higher modes rise as the vertex angle of a gyeong changes from 90 degrees to 180 degrees. The curvatures of the baseline affect the tuning of the stone, but the effects are smaller than those of the vertex angle. The geometry of the gyeong affects the tuning of the stone. The pyeonjong covers one and one third octave from 267.95 Hz to 634.74 Hz. The nominal frequency of the first bell, whangiong , is 267.95 Hz. The second mode (i.e. (2,0)[sub b]) is tuned to about 1.09 times the nominal frequency (i.e. (2,0)ₐ) mode. The third mode (i.e. (3,0)[sub b]) is tuned to about 2.62 times the nominal frequency. The fourth mode (3,0), is tuned 2.72 times the nominal frequency, a perfect fourth plus 39 cents above the octave. Mode shapes of the bells, determined by electronic TV holography, are described by m, the number of nodal meridians and n, the number of nodal circles. Like Chinese two-tone bells, the bells in pyeonjong have "a" and "b" modes with the same (m, n) designation. The mode shapes agree very well with the results from former studies.

Comments

Includes bibliographical references (pages [206]-211).

Extent

xviii, 228 pages (some color pages)

Language

eng

Publisher

Northern Illinois University

Rights Statement

In Copyright

Rights Statement 2

NIU theses are protected by copyright. They may be viewed from Huskie Commons for any purpose, but reproduction or distribution in any format is prohibited without the written permission of the authors.

Media Type

Text

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