Dynamics & Vibration Research Group
Mechanics, Materials, and Design
Acoustics of the Violin
The violin has been an intriguing problem to scientists for the last century and more.
Why is there such an enormous price differential between the best and worst violins, when they are apparently
very similar wooden boxes? Work has been done on this subject in Cambridge for the last 25 years. The large
questions still cannot be answered with confidence, but great progress has been made on understanding some
aspects of the problem, and the jigsaw is gradually being filled in.
A major aim of bowed-string research is to understand why one violin may be perceived as "easier to play" than another. Theoretical models of the bowed string have developed to the level where they are believed to include all the main physical effects. These models can now be used in systematic simulation studies, to address questions such as:
Studies of wood, varnish and other treatment methods have also grown out of collaboration with instrument makers. We have obtained from violin restorers some small fragments of old instruments, and these have been compared in the Scanning Electron Microscope with samples from contemporary makers. Forensic studies of this nature have provided data about historical practices of wood selection and treatment. One particular clear conclusion concerned "ponding" of wood. If softwood is stored for a few weeks in water, bacterial action can lead to greater porosity of the cellular structure, which in turn allows deeper penetration by varnish or other wood treatments. It had been suggested that this practice might have been followed by the classical makers, perhaps thereby achieving some desirable modification of wood properties. The evidence was unequivocal: classical Italian makers did not pond their wood. No examples of bacterial degradation were found in any sample examined.
Project Details
Work has focused on three particular aspects of violin physics: (1) the motion of a string excited by bowing; (2) the vibration and damping behaviour of the violin body; and (3) the material properties of the wood and coatings applied to it.A major aim of bowed-string research is to understand why one violin may be perceived as "easier to play" than another. Theoretical models of the bowed string have developed to the level where they are believed to include all the main physical effects. These models can now be used in systematic simulation studies, to address questions such as:
- For a given bow gesture, which of the various possible regimes of string vibration actually occurs, and how long is the initial transient?
- How should the model parameters be chosen so as to maximise the likelihood of obtaining the "correct" string motion, known as the Helmholtz motion?
Studies of wood, varnish and other treatment methods have also grown out of collaboration with instrument makers. We have obtained from violin restorers some small fragments of old instruments, and these have been compared in the Scanning Electron Microscope with samples from contemporary makers. Forensic studies of this nature have provided data about historical practices of wood selection and treatment. One particular clear conclusion concerned "ponding" of wood. If softwood is stored for a few weeks in water, bacterial action can lead to greater porosity of the cellular structure, which in turn allows deeper penetration by varnish or other wood treatments. It had been suggested that this practice might have been followed by the classical makers, perhaps thereby achieving some desirable modification of wood properties. The evidence was unequivocal: classical Italian makers did not pond their wood. No examples of bacterial degradation were found in any sample examined.
Relevant/Recent Publications
- McIntyre ME, Schumacher RT, Woodhouse J. 'On the oscillations of musical instruments', J. Acoustical Society of America,74, 1325-1345, (1983).
- Barlow CY, Woodhouse J. 'Of old wood and varnish: peering into the can of worms', J. Catgut Acoustical SocietySeries II, 1(4), 2-9, (1989).
- Barlow CY, Woodhouse J. 'Bordered pits in spruce from old Italian violins', Journal of Microscopy,160, 203-211, (1990).
- Woodhouse J. 'On the playability of violins: Part 1 Reflection functions', Acustica,78, 125-136, (1993).
- Woodhouse J. 'On the playability of violins: Part 2 Minimum bow force and transients',Acustica,78, 137-153, (1993).
- Kahle E, Woodhouse J. 'The influence of cell geometry on the elasticity of softwood', J. Mater. Sci.,29, 1250-1259, (1994).
- Schumacher RT, Woodhouse J. 'The transient behaviour of models of bowed-string motion', Chaos,5, 509-523, (1995).
- Pitteroff R, Woodhouse J. 'Mechanics of the contact area between a violin bow and a string Part I: reflection and transmission behavoiur', Acustica/Acta Acustica,84, 543-562, (1998).
- Pitteroff R, Woodhouse J. 'Mechanics of the contact area between a violin bow and a string Part II: simulating the bowed string', Acustica/Acta Acustica,84, 744-757, (1998).
- Pitteroff R, Woodhouse J. 'Mechanics of the contact area between a violin bow and a string Part III: parameter dependence', Acustica/Acta Acustica,84, 929-946, (1998).
- Woodhouse J. 'The acoustics of "AO-BO mode matching" in the violin', Acustica/Acta Acustica,84, 947-956, (1998).
Principal Investigator & Researchers
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