Performance expression synthesis for bowed-string instruments using ``Expression Mark Functions'
Yuma Koizumi, Katunobu Itou · Proceedings of meetings on acoustics · 2012
This paper proposes a method to synthesize the performance expression of bowed-string instruments using transfer functions for expression marks. ``Expression mark functions' are estimated from recorded performance sounds using string motion spectra and filtering the instruments' resonance properties. Bowed-string motion forms a triangular wave called the Helmholtz motion and can be determined from the bowed-string position. Deviations in waveform of expression performance are estimated by non-negative matrix factorization. The resonance properties of instruments are measured as time-stretched-pulse responses using a ``direct-drive speaker.' Expression mark functions are extracted by decomposing the actual performance sound using these data. To evaluate the synthesized sound quality, it is compared using expression mark functions and wavetable synthesis method. For all expression marks, almost all audience members could recognize changes in tone. MOS for ``dolce' and ``marcato' were scored 4.0.