On the "Bridge Hill" of the Violin

Many excellent violins show a broad peak of response in the vicinity of 2.5 kHz, a feature which has been called the "bridge hill". It is demonstrated using simplified theoretical models that this feature arises from a combination of an in-plane resonance of the bridge and an averaged version of the response of the violin body at the bridge-foot positions. Using a technique from statistical vibration analysis, it is possible to extract the "skeleton" of the bridge hill in a very clear form. Parameter studies are then presented which reveal how the bridge hill is affected, in some cases with great sensitivity, by the properties of the bridge and body. The results seem to account for behaviour seen in earlier experimental studies, and they have direct relevance to violin makers for guiding the adjustment of bridges to achieve desired tonal quality.