1. Perception and production ofcomplex bowing movements inviolin performanceErwin SchoonderwaldtMatthias DemoucronEckart AltenmllerMarc Leman

2. Overview Basic introduction Coordination model of complex bowinggestures Studies Perception experiment Mocap experiment Conclusions 3. Bow forceBow-bridge distanceBowing gestures Control of sound by means of main bowingparameters 4. Bowing gestures Control of sound by means of main bowingparameters Timing Anticipation Expression 5. Bowing gestures Physical constraints Excitation mechanism (stick-slip interactionbetween bow and string) Instrument response (playability) Geometry of the instrument (e.g., playingdifferent strings) Biomechanical and physiological constraints Musical constraints 6. Complex bowing gestures 7. Complex bowing gestures Working definition:Bowing gestures involving bow changesand string crossings 8. Complex bowing gestures Working definition:Bowing gestures involving bow changesand string crossings Repetitive bowing patterns Circles: played across two strings Figure-of-eight: played across three strings 9. Two movement componentsRadial component(Bowing direction) 10. Two movement componentsRadial component(Bowing direction)Tangential component(String crossings) 11. String crossingRadial component(Bowing direction)Tangential component(String crossings) 12. Aims To study the coordination between bowchanges and string crossings Relative timing controlled via relative phasebetween radial and tangential movementcomponents Auditory-motor interaction Relation between auditory perception and motorbehavior 13. Coordination modelBow velocityBow forceInclination Bow change00String 1 (old)String 2 (new)String crossingTime 14. Coordination modelBow velocityBow forceInclinationBow change00String 1 (old)String 2 (new)String crossingTimeRelative phase 15. Coordination modelBow velocityBow forceInclination00String 1 (old)String 2 (new)String crossingString-crossingrangeBow changeTime 16. Coordination model Two main parameters Relative phase between bow velocity and bowinclination movements Normalized string crossing range r(string crossing range / inclination extent)r2D coordinationspacebow change outsidestring crossing range 17. Trade offBow velocityBow forceInclination00String 1 (old)String 2 (new)String crossingBuild-up of bow forceTimeQuality ofmain attack 18. Trade offBow velocityBow forceInclination00String 1 (old)String 2 (new)String crossingNew string when enteringthe string-crossing regionTimeFalse attacks(Type I) 19. Trade offBow velocityBow forceInclination00String 1 (old)String 2 (new)String crossingOld string at bow changeTimeFalse 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 virtualviolin (physical model, Max/MSP) Live control of coordination parameters usingsimple 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. Results95% conf. int. per binfixed 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 about 15 deg 28. Back to performance Motion capture experiment 22 violinists (advanced amateurs, majoringstudents, established professionals) Repetitive bowing patterns (variety conditions) Feature extraction Bowing parameters, bow angles rel. to violin Relative phase (Hilbert transform) String-crossing features 29. ExampleCounter-clockwiseClockwise 30. Results 31. Results 32. Conclusions Coordination in complex bowing patterns Large general agreement between perception andperformance (phase and range parameters) 33. Conclusions Coordination in complex bowing patterns Large general agreement between perception andperformance (phase and range parameters) Complex bowing trajectories emerge fromauditory-motor interaction 34. Conclusions Coordination in complex bowing patterns Large general agreement between perception andperformance (phase and range parameters) Performance No clear distinction between levels of expertise Large individual differences 35. Conclusions Coordination in complex bowing patterns Large general agreement between perception andperformance (phase and range parameters) Performance No clear distinction between levels of expertise Large individual differences Coordination model Additional degrees of freedom in performance 36. AcknowledgmentsMore information:http://www.bowing3d.infoschoondw@gmail.comMany thanks to:Lambert ChenMarta Beauchamp & Liming WuAlexander von Humboldt Stiftung