Nonlinear Modeling and Synthesis of the Kantele – a Traditional Finnish String Instrument

Vesa Välimäki, Matti Karjalainen, Tero Tolonen, and Cumhur Erkut

Helsinki University of Technology, Laboratory of Acoustics and Audio Signal Processing, P.O. Box 3000, FIN-02015 HUT, Espoo, Finland

E-mail: vesa.valimaki@hut.fi, matti.karjalainen@hut.fi, tero.tolonen@hut.fi, cumhur.erkut@hut.fi

ABSTRACT

We apply a recently developed nonlinear string synthesis algorithm to modeling and synthesis of the kantele, which is a plucked string instrument used in traditional Finnish music for the past few thousand years. The new model combines formerly proposed linear plucked-string models with recent nonlinear extensions. As a result, a dual-polarization nonlinear model is obtained where the difference in the effective string length in two polarizations is accounted for, together with effects caused by the yielding termination of kantele strings and tension modulation. Calibration of model parameters is discussed. The model is also applicable to physical modeling of other plucked string instruments.

Keywords: audio signal processing, physical modeling of musical instruments, sound synthesis, musical acoustics, vibrating string, waveguide modeling

This paper was published in the Proceedings of the 1999 International Computer Music Conference, pp. 220-223, Beijing, China, Oct. 22-27, 1999.

• The complete paper in PostScript format (261 kB)
• The complete paper in PDF format (63 kB)
• Sound Example 1: The difference in the length of the delay lines of the two models can be estimated based on the beating of kantele tones. We analyzed the envelope of the first harmonic of recorded kantele tones, and extracted the beating frequency by fitting a sine wave using the least squares method. We use an average of two cases, a horizontal and a vertical pluck. This method yields a good estimate of the difference of the two polarizations.
• Sound Example 2: The output signal of the horizontal string model.
• Sound Example 3: The output signal of the vertical string model.
• Sound Example 4: Tension Modulation Driving Force output.
• Sound Example 5: Dual-mode kantele string model output, including the tension modulation driving force.

This URL: http://www.acoustics.hut.fi/~vpv/publications/icmc99.htm
Last modified: December 31, 1999
Author: Vesa Välimäki