Violin Resonances
C. L. Caldwell · The Journal of the Acoustical Society of America · 1963
A fruitful method of studying the action of the violin is to consider it as a system of generators (the strings) and resonators (the body). The body has many resonances, some being caused by the air inside, others being caused by the wood. These two sets of resonances were separated. A tiny microphone was placed inside a violin, which was then buried in sand to dampen the wood resonances. The F holes were kept clear. The violin was placed in a swept-frequency sound field. This gave the air resonances alone. In addition to the main Helmholtz resonance, others were found, together with notches in response due to standing waves. Next, a magnetic driver and a pickup were attached to the violin, which was placed in a vacuum system. This yielded the wood resonances alone. The peaks became more prominent in the absence of radiation resistance. Finally, the total response of the violin was obtained in air, using the magnetic driver and both the microphone and the magnetic pickup. Since the pickup does not respond to the main air resonance, interactions between the two sets of resonances are weak.