Free Plate Tuning, Part One: Theory

by Alan Carruth

Originally published in American Lutherie #28, 1991 and Big Red Book of American Lutherie Volume 3, 2004

See also,
Free Plate Tuning, Part Two: Violins by Alan Carruth
Free Plate Tuning, Part Three: Guitars by Alan Carruth



I started learning free plate tuning on violins and violas more than ten years ago from Carleen Hutchins. For those who have not had the pleasure of her acquaintance, Carleen is one of the founders of the Catgut Acoustical Society and its permanent secretary. She is an able scientist, a great teacher, a fine luthier, and a self-confessed mediocre violist. While working with physicist Frederick Saunders almost thirty years ago she helped rediscover and update the old Chladni method of visualizing the vibrations of plates. Her subsequent research, using Chladni patterns as a window into the differences between good and poor violins earned her a silver medal from the Acoustical Society of America.

Violin makers have traditionally used some variant of “tap tone” tuning to guide them in working out the final graduations of the top and back plates. Although the technique seems simple and organic on the face of it, it is in fact very complex. It takes a long time, as well as a good ear and a lot of talent, to learn to tune plates by tap tone. Even those who are good at it don’t always succeed. Felix Savart, back in the 19th century, tried to adapt Chladni’s method to research on violin acoustics, but the technology wasn’t there. Now we have the means, and as we gain more understanding of how the instruments work, we also gain more control over the sound.

And it doesn’t only work on violins. Fred Dickens, Graham Caldersmith, and Gila Eban have all done major work in applying the principles of violin acoustics to guitar construction. Of course, there are differences and it takes time and effort to sort them out, but physics is physics, or, as a friend of mine said, “it all comes down to F=mA in the end.” I have found these techniques to be useful, and sharing useful techniques is what the Guild is all about.