UBC Undergraduate Research

The effects of violin varnish on the acoustic properties of Picea Engelmannii Hudoba de Badyn, Mathias


Acoustic spectral analysis was performed on plates of Picea Engelmannii (Engelmann Spruce) before and after application of one of 3 types of varnish. The first overtone of each sample was driven through tapping by hand, and analyzed through a Fast Fourier Transform algorithm. The resulting acoustic spectrum was used to determine the frequency, quality factor Ǫ, attenuation rate and damping coefficient ζ changes as a result of the varnish application. A colophony-linseed oil and shellac-spirit varnish, and polyester lacquer were tested. A formula for predicting frequency shift based on mass and thickness of varnish added was determined, and varying trends of Q, α and ζ were reported. Wave propagation and the plate mechanics were analyzed.

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Attribution-NonCommercial-NoDerivatives 4.0 International