The Ruan and the Yueqin

1. The Ruan and the Yueqin Measurement and analysis of sound radiation patterns of the Chinese Ruan and the Yueqin Florian Pfeifle // Musicological Institute // University of Hamburg

2. Overview Ruan Yueqin

3. Overview Ruan Yueqin • Round resonance body • Round resonance body

4. Overview Ruan Yueqin • Round resonance body • Sound holes • Round resonance body • One small sound hole

5. Overview Ruan Yueqin • Round resonance body • Sound holes • Bridge • Round resonance body • One small sound hole • Strings coupled to body

6. Overview Ruan Yueqin • Round resonance body • Sound holes • Bridge • Round resonance body • One small sound hole • Strings coupled to body Different timbre!

7. Overview Ruan Yueqin • Round resonance body • Sound holes • Bridge • Round resonance body • One small sound hole • Strings coupled to body Different timbre!

8. Methods Measurement Modeling Pseudo-Spectral Finite Difference Scheme [Fornberg, 1996] Time-stepping with NVS-Algorithm Whole instrument geometries are modeled • Minimal Energy Method [Bader, JASA 2010] • Reconstruction of the sound radiation • All instruments are measured with a 11x11 microphone Array • All depicted sound radiation are the result of a single measurement (a knock, or a string)

9. Ruan Measurements

10. Spectrum of the back-plate

11. Spectrum of the back-plate 325 Hz Lighter color = higher sound pressure level

12. Spectrum of the back-plate 456 Hz

13. Spectrum of the back-plate 702 Hz

14. Spectrum of the back-plate 1015 Hz

15. Spectrum of the front-plate Helmholtz Frequency (extended Rayleigh notation):

16. Spectrum of the front-plate 317 Hz

17. Spectrum of the front-plate 336 Hz

18. Spectrum of the front-plate 406 Hz

19. Spectrum of the front-plate 451 Hz

20. Spectrum of the front-plate 817 Hz

21. Spectrum of the front-plate 578 Hz

22. Spectrum of the front-plate 656 Hz

23. Spectrum of the front-plate 1037 Hz

24. Air modes // One sound hole closed

25. Air modes // One sound hole closed

26. Ruan Intermediate Results • Two peaks in the spectrum are air modes • Characteristic modes appear twice in the spectrum: • Front-plate radiation only

27. Ruan Intermediate Results • Two peaks in the spectrum are air modes • Characteristic modes appear twice in the spectrum as: • Coupled air-front-plate radiation

28. First vs. second string

29. First vs. second string fundamental 96,8Hz 148Hz

30. First vs. second string first partial

31. First vs. second string third partial

32. Yueqin Measurements

33. Spectrum of the front plate

34. Spectrum of the front plate 233 Hz

35. Spectrum of the front plate 379 Hz 420 Hz

36. Spectrum of the front plate 530 Hz 684 Hz 1048 Hz

37. Intermediate Results • The fundamental frequency of the Yueqins front-plate is lower • Spectrum of the Yueqin is “smoother” • The Helmholz of the Ruan plays a crucial role in the sound radiation • Other air modes of the Ruan are important too

38. Ruan and Yueqin Simulation

39. Model of the Ruan without soundholes

40. Model of the Ruan with sound holes

41. Model of the Yueqin

42. Yueqin simulated sounds • Yueqin without hole • Yueqin without air • Yueqin with hole • Yueqin with hole and frets

43. Results • The difference in timbre is linked to the presence of the front holes • The air volume not only influences the sound radiation but also the vibrational behavior of the front-plate • The position of the bridge influences the excited spectrum on the front-plate

44. Further Work • Research the effect of the air volume and the sound hole of the Yueqin • Research the interaction between the air and the front-plate • Research and refine the boundary conditions for both front-plates

45. Further Work • Research the effect of the air volume and the sound hole of the Yueqin • Research the interaction between the air and the front-plate • Research and refine the boundary conditions for both front-plates Questions // Remarks?