Selecting Guitar Wood Based on Material Properties, Part Two

by Trevor Gore

Originally published in American Lutherie #119, 2014

see also,
Selecting Guitar Wood Based on Material Properties, Part One by Trevor Gore



Braces in a guitar serve two main purposes: to limit the soundboard’s deflection due to the bending moment applied by the static string loads, and to control how the soundboard subdivides into separate vibrating areas. How the second matter is handled is arbitrary, depending on the acoustical preferences of the builder, but the first matter is nonnegotiable if the instrument is to survive the applied string loads. So our concern here is principally with the first matter.

Spruce has been the wood of choice for guitar braces for over a hundred years and a relatively simple analysis will demonstrate why this is the case. To illustrate the point, a possible alternative wood, in this case western red cedar, has been chosen for comparative purposes. The significant material properties are tabulated below (Table 1), these values being for specific samples that I tested.