Jeffrey R. Elliott Open Harmonic Bar Classical Guitar

by Jeffrey R. Elliott

Originally published in American Lutherie #127, 2016



The earliest example I know of a guitar with an open harmonic bar was made by Antonio de Torres in 1856 (“La Leona,” FE 04). Originally as a design element used in conjunction with a tornavoz (seldom used today, it has faded into obscurity), the open harmonic bar has survived separately as an essential feature in some top-bracing designs, and many of history’s most noted makers have tried their version of it, although infrequently. The most successful example, in my opinion, was Julian Bream’s 1973 José Romanillos guitar, which inspired me to try it. However, the historic design has a serious inherent structural risk, and if underbuilt, the guitar can also be so overly responsive that the fundamental becomes clouded. For many years I wondered if I could adapt the design so that it avoided both the structural and sonic risks yet still produced the sound I was after, and in early 1990 I produced this design.

I believe the design allows the surfaces of the waist and upper bout to work in concert with the lower bout, so that the entire top responds more fully, and all at once. Based on a symmetrical layout, I redefined the design and made the following changes: 1) created apertures in all three harmonic bars and extended them to 1CM from the periphery and left them solid for their central 10CM of length; 2) dropped the cutoff bars altogether, and extended the fans to 15MM from the periphery; 3) installed a soundhole reinforcement ring and extended the outer two fans on both sides into it; 4) used only one upper bout strut on each side, and at an angle to the top’s grain; 5) widened the bridge patch 3MM both in front and behind; 6) made both the soundhole and fingerboard supports .5MM thicker; 7) graded the fan bracing as per the plan specifications, concentrating stiffness and mass in the center, and gradually loosening toward the periphery in a symmetrical pattern; 8) scalloped the surface of the end block that meets the top so that it continued the same spatial contact of the corner blocks; and 9) while I believe these changes have both expanded and refined the design, the most crucial addition was the .5MM-thick relief pads just under the harmonic-bar openings, let in 2MM on their ends. In over twenty-six years, none of my guitars have cracked under those openings, which has been the main structural risk with earlier open-bar designs; nor do they inhibit the purpose of opening the harmonic bars in the first place.