The Influence of Multiple Variables on Torsion in the Bowed E-String

  • Robert Wilkins University of Western Australia
  • Hongmei Sun University of Western Australia
  • Jie Pan University of Western Australia


This research is an empirical exploration of the torsional vibration in the bowed violin E-string
that is the cause of the E-string whistle. Multiple measurements are taken directly from the
violin string with a laser vibrometer. Evidence is presented that shows bow velocity as an
essential part of a multi-variable explanation. Other variables include forced resonances in the
E-string coupled from notes bowed on the A-string that influence the start-up of torsional
vibration and natural frequencies of the transverse vibration in the A-string and E-string that are
coincident and/or non-coincident with the natural frequency of torsion. An explanation is given
concerning the bowing features of torsion that effectively block the normal Helmholtz resonance
in the open E-string and allow both forced and natural E-string frequencies that have coincident
harmonics with the torsion frequency to phase-lock with torsion and couple in super-position.

Author Biographies

Robert Wilkins, University of Western Australia

Robert Wilkins learned the violin from the age of ten. He has played in amateur orchestras for more than thirty-five years and together with his wife, a cellist, organizes a string orchestra. He made his first violin in 1985 after close association with the late Dr Carleen Hutchins and in the workshop of the late M. Peabody of Boston. Since then he has made 53 violins, violas and cellos. He has a diploma in electrical theory and practice, a BA (Experimental Research Psychology), LTh, Dip.ThS. (Theology), M.Ed, and Ph.D. (Cognitive Psychology). For more than twenty years Wilkins taught at Curtin University of Technology. His specialties include research and measurement, and the development of cognition. He has authored two textbooks and published forty journal articles on a diverse range of topics in education, cognitive psychology, philosophy and more recently, violin acoustics. He is a member of the Australian Rationalist Society. His interest in violin acoustics is pursued through the auspices of the UWA School of Mechanical Engineering, Center for Vibration, Dynamics and Acoustics where he is an honorary research associate and co-supervisor for students doing theses in violin related projects.

Hongmei Sun, University of Western Australia

Hongmei Sun is a research officer in the Centre for Acoustics, Dynamics and Vibration at the school of Mechanical and Engineering, University of Western Australia. Over the past 16 years, she has obtained substantial experience in the areas of acoustics and vibration. She is in the final stage of a Ph.D. and has been involved in many research projects in the area of room acoustics, industrial noise control and music acoustics. She has conducted experimental studies and supervised final year students on a wide variety of projects including some involving the violin and cello.

Jie Pan, University of Western Australia

Jie Pan is a Winthrop professor in the School of Mechanical Engineering, University of Western Australia, where he is also the Director for the Centre for Acoustics, Dynamics and Vibration. Over the last 20 years, he has been working on many projects in the area of room acoustics, active noise control and structural acoustics. Music acoustics is a special interest. He has developed expertise in the acoustical mechanisms of bells, flutes and string instruments. Pan's teaching covers control and mechatronics, advanced control, vibration and signal processing, and acoustical engineering.