Paul S. Veneklasen & Associates, 1711 16th St., Santa Monica, CA 90404
Univ. of Wales College of Cardiff, P. O. Box 913, Cardiff CF2 3YB, UK
Some of the research undertaken by the Cardiff group to try to establish relationships between the classical guitar's construction and its acoustical output are reviewed. Real instruments have been studied using techniques such as holographic interferometry, and the structural vibrations and associated radiation fields have been modeled using finite-element analysis and boundary-element methods. Primitive psychoacoustical tests have established that radiated frequency components of plucked notes are important in recognizing individual instruments. Large amounts of data, collected over the years, have clearly demonstrated that there are no simple relationships between the modal properties of instruments and their estimated ``quality.'' Similar conclusions have, of course, been drawn by other workers in this field. Recently, the authors have concentrated more on determining the precise role played by individual modes in coupling the strings to the body and in radiating energy to the surrounding air; it is felt that this sort of detail is more indicative of the instrument's final acoustical action. These investigations emphasize the importance of the precise shapes of modes, particularly in the vicinity of the bridge. A discussion of the ways in which the luthier can fine-tune mode shapes and hence maintain control during instrument manufacture is included.