Author

Jianming Tsai

Publication Date

1991

Document Type

Dissertation/Thesis

First Advisor

Rossing, Thomas D., 1929-

Degree Name

M.S. (Master of Science)

Department

Department of Physics

LCSH

Music--Acoustics and physics||Yang chʻin

Abstract

The yangqin is a Chinese hammered dulcimer with a trapezoidal soundboard. The soundboard, which is crowned to a height of 4 cm in the center, is supported by 7 unequally-spaced transverse ribs. Vibrational modes of the soundboard in the frequency range 100 - 7 00 Hz have been studied by impact modal analysis as well as by scanning with an accelerometer as the soundboard is driven by a small shaker. Nodal lines tend to follow the stiff transverse ribs. Modal shapes indicate that the transverse stiffness is substantially greater than the longitudinal stiffness in the braced soundboard. The impedance at most points on the bass bridges shows a maximum around 100 Hz and then falls off at roughly 6 dB/octave. The impedance on the treble bridges, on the other hand, reaches a broad maximum around 2 kHz and falls off quite slowly with frequency, at least up to 5 kHz. Experimental values of mode frequencies fit well to the analytical ones obtained by considering the trapezoidal ratio and the curvature effect. The soundboard boundary conditions are somewhat complicated by the frame. They appear to be close to simply-supported edges at the lower frequencies and close to clamped edges at high frequencies.

Comments

Includes bibliographical references (pages [72]-74).

Extent

ix, 74 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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