A technique used by luthiers for shaping the braces mounted to the underside of an acoustic guitar’s top, typically by shaving away wood in the middle of the brace. Martin used this technique for their famous vintage “Pre-war” guitars built prior to 1944. (From 1945-1976, Martin used “straight” top braces, and since 1977 has offered guitars with both straight and scalloped braces.) There main reason luthiers scallop braces is to reduce brace mass for better top flexibility. The result is more bass response – some players like this, some don’t. Today many manufacturers offer scalloped bracing on some or all of their guitar models.