Savart Journal

science and technology of stringed musical instruments

Frequency Response Evaluation of Acoustic Guitar Modifications

D.P. Hess


This paper investigates the effect of various modifications to an acoustic steel string guitar on low frequency dynamics and sound pressure level. Modifications include string tension, sound-hole area and depth, bridge pin mass, top plate mass, stiffness and damping. Frequency response measurements are provided for all modifications considered. A lumped parameter model is found to capture the changes in measured frequency response and sound pressure level remarkably well. The measurements and model results are found to be consistent with player and listener perceptions in most cases. Results from a parametric study identify a unique combination of physical parameter adjustments for broadband increase in sound level. In addition, a technique for obtaining low-frequency free-field sound pressure without the need for an anechoic chamber is successfully applied to the acoustic guitar. This technique uses near-field, time-selective impulse response sound pressure measurements to determine the low-frequency free-field sound pressure.

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Article published Jul 5, 2013.
This article has been accessed 14371 times since publication.


The Savart Journal is published in collaboration with the Guild of American Luthiers.

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D.P. Hess
Department of Mechanical Engineering University of South Florida Tampa, Florida
United States

D.P. Hess is a Professor of Mechanical Engineering at the University of South Florida. He received his Ph.D. from the State University of New York at Buffalo in 1991. His interests and contributions are in the areas of vibrations, tribology, acoustics, controls, and fasteners. He is a recipient of both the NSF Presidential and Career awards and numerous other grants from NSF, NASA and industry for work in these areas.