Estimation of a violin source/filter model
James W. Beauchamp, Ashwin K. Vijayakumar · The Journal of the Acoustical Society of America · 2015
The source/filter model is often mentioned in the acoustics and signal processing literature (e.g., Gold and Morgan, Speech and Audio Signal Processing, Wiley) but has seldom been implemented for musical instrument sounds. An exception was by Mathews and Kohut, (“Electronic simulation of violin resonances,” J. Acoust. Soc. Am. 53(6) (1973)). In this study, we attempt to separate source harmonic amplitudes from a violin filter characteristic using harmonic tracking analysis of glide tones performed in an anechoic chamber. Assuming that the violin bridge/body constitutes a linear system, if string force harmonics are constant over pitch, they should sweep out frequency responses that only differ by constant amplitude ratios over their overlap regions. Departures from constant ratio behavior can be interpreted in terms of source spectra that change with fundamental frequency. Interpretation and detailed results of this analysis are given.