This document discusses coordination of complex bowing movements in violin performance. A study examined perception and production of bowing patterns involving bow changes and string crossings. A coordination model was proposed using two parameters: relative phase between bowing directions and normalized string crossing range. A perception experiment found violinists preferred a phase difference with string crossings timed earlier than bow changes. A motion capture study of violinists found their bowing coordination agreed with perceptual preferences, though individual differences existed. The coordination model provided insight into complex bowing gestures in violin performance.

1. Perception and production of
complex bowing movements in
violin performance
Erwin Schoonderwaldt
Matthias Demoucron
Eckart Altenmüller
Marc Leman

2. Overview
• Basic introduction
• Coordination model of complex bowing
gestures
• Studies
– Perception experiment
– Mocap experiment
• Conclusions

3. Bow force
Bow-bridge distance
Bowing gestures
• Control of sound by means of main bowing
parameters

4. Bowing gestures
• Control of sound by means of main bowing
parameters
• Timing
• Anticipation
• Expression

5. Bowing gestures
• Physical constraints
– Excitation mechanism (stick-slip interaction
between bow and string)
– Instrument response (playability)
– Geometry of the instrument (e.g., playing
different strings)
• Biomechanical and physiological constraints
• Musical constraints

6. Complex bowing gestures

7. Complex bowing gestures
• Working definition:
Bowing gestures involving bow changes
and string crossings

8. Complex bowing gestures
• Working definition:
Bowing gestures involving bow changes
and string crossings
• Repetitive bowing patterns
– Circles: played across two strings
– Figure-of-eight: played across three strings

9. Two movement components
Radial component
(Bowing direction)

10. Two movement components
Radial component
(Bowing direction)
Tangential component
(String crossings)

11. String crossing
Radial component
(Bowing direction)
Tangential component
(String crossings)

12. Aims
• To study the coordination between bow
changes and string crossings
– Relative timing controlled via relative phase
between radial and tangential movement
components
• Auditory-motor interaction
– Relation between auditory perception and motor
behavior

13. Coordination model
Bow velocity
Bow force
Inclination Bow change
0
0
String 1 (old)
String 2 (new)
String crossing
Time

14. Coordination model
Bow velocity
Bow force
Inclination
Bow change
0
0
String 1 (old)
String 2 (new)
String crossing
Time
Relative phase
φ

15. Coordination model
Bow velocity
Bow force
Inclination
0
0
String 1 (old)
String 2 (new)
String crossing
String-crossing
range
Bow change
Time

16. Coordination model
• Two main parameters
– Relative phase φ between bow velocity and bow
inclination movements
– Normalized string crossing range r
(string crossing range / inclination extent)
r
φ2D coordination
space
bow change outside
string crossing range

17. Trade off
Bow velocity
Bow force
Inclination
0
0
String 1 (old)
String 2 (new)
String crossing
Build-up of bow force
Time
Quality of
main attack

18. Trade off
Bow velocity
Bow force
Inclination
0
0
String 1 (old)
String 2 (new)
String crossing
New string when entering
the string-crossing region
Time
False attacks
(Type I)

19. Trade off
Bow velocity
Bow force
Inclination
0
0
String 1 (old)
String 2 (new)
String crossing
Old string at bow change
Time
False attacks
(Type II)

20. Trade off
• Perceptual quality of transition
– Quality of main attack
– False attacks (two types)
– Remaining string vibrations on „old“ string
(ringing)
• No obvious optimal solution

21. Trade off
• Perceptual quality of transition
– Quality of main attack
– False attacks (two types)
– Remaining string vibrations on „old“ string
(ringing)
• No obvious optimal solution
 Perceptual experiment

22. Perceptual experiment
• Coordination model implemented in a virtual
violin (physical model, Max/MSP)
• Live control of coordination parameters using
simple sliders
• Bowing patterns across 2 strings

23. Perceptual experiment
• 16 participants (experienced string players)
• Variety of stimuli (8)
– 2 note patterns
– Three string combinations
– Forte and piano
• 4 conditions (1D and 2D sliders)

24. Perceptual experiment

25. Results

26. Results
95% conf. int. per bin
fixed r conditions

27. Summary
• Clear phase difference
– String crossing timed earlier than bow changes
• Weak increase of phase difference with range
• Optimum coordination???
– r about 0.3
– φ about 15 deg

29. Back to performance
• Motion capture experiment
– 22 violinists (advanced amateurs, majoring
students, established professionals)
– Repetitive bowing patterns (variety conditions)
• Feature extraction
– Bowing parameters, bow angles rel. to violin
– Relative phase (Hilbert transform)
– String-crossing features

30. Example
Counter-clockwise
Clockwise

31. Results

32. Results

33. Conclusions
• Coordination in complex bowing patterns
– Large general agreement between perception and
performance (phase and range parameters)

34. Conclusions
• Coordination in complex bowing patterns
– Large general agreement between perception and
performance (phase and range parameters)
 Complex bowing trajectories emerge from
auditory-motor interaction

35. Conclusions
• Coordination in complex bowing patterns
– Large general agreement between perception and
performance (phase and range parameters)
• Performance
– No clear distinction between levels of expertise
– Large individual differences

36. Conclusions
• Coordination in complex bowing patterns
– Large general agreement between perception and
performance (phase and range parameters)
• Performance
– No clear distinction between levels of expertise
– Large individual differences
• Coordination model
– Additional degrees of freedom in performance

37. Acknowledgments
More information:
http://www.bowing3d.info
schoondw@gmail.com
Many thanks to:
Lambert Chen
Marta Beauchamp & Liming Wu
Alexander von Humboldt Stiftung