Physical Model of the Chinese Yehu for Sound Synthesis
The yehu is a Chinese bowed string instrument featuring a resonator carved from a coconut shell, a seashell-based bridge, and two silk strings. This paper proposes a physical model of the yehu and reports on simulations using a finite-difference scheme with measurement-based physical characterization. The proposed model consists of two stiff strings coupled at the bridge, a bow with elastic bow hairs, a stopping finger, and a modal model of the bridge. A non-iterative solver based on energy quadratization is used to model the finger–string contact force, while an iterative solver is used for elasto-plastic bow-string friction force. The bridge-body model is based on a modal characterization obtained from the measured bridge admittance. The measured radiation transfer function is represented as a bank of parallel second-order filters and is applied to the simulated bridge force to incorporate body radiation characteristics. Finally, computational performance tests are conducted, showing that the proposed model is capable of real-time computation.