Acoustics of the violin as a function of its parts

Abstract

During the last 20 years, Carleen Hutchins has successfully developed methods for testing and tuning of free top and back plates with Chladni patterns. Her methods have been successfully used by other makers in Sweden too. For the engineer/physicist, it is, however, difficult to understand how and how much of the quality of a violin is predicted by the free‐plate tuning. Therefore, data from KTH experiments have been used to investigate relations between free plates and assembled violins. Eigenmodes of free top and back plates have been calculated and measured. Effects of thinning the top plate free and in an assembled violin have also been investigated. Comparison of the frequency of the main resonance of the violin (T1 at about 500 Hz with mainly the top plate vibrating along the bass bar side) is affected somewhat similarly to thinnings of the ring mode of the free plate (i.e., it is most sensitive to off‐center thinnings and it should be a balance in stiffness along and across). Thus the present result is qualitatively in agreement with that of Dr. Hutchins—the ring mode of the free plate is the most important for tuning. Recent playing tests imply, however, that the lengthwise stiffness of the top plate is more important than the one across. [Work together with Luleå Technical University, L. Frydén, Stockholm, L and B. Niewczyk, Poznan.]