Voiced and Scalloped Braces
In the 50's & 60's, acoustic
guitars were built for strength to make it through the warranty period
unfortunately these guitars didn't always sound so good. If an acoustic
guitar is braced too heavily, it will sound dead. If an acoustic guitar
is braced a little too lightly, it may sound good for a while but then
pull itself apart. The trick is to find the perfect size braces that
sound good but are strong enough to last a lifetime or two.
An ordinary brace is straight with tapered ends. On early Martin guitars before 1944, the tops of the braces were hand shaved. The top edge of the brace was shaped sort of like the silouette of a suspension bridge. To make a long story short, Martin quit doing this because customers complained about the belly of the guitars bulging which wasn't necessarily bad.
Certain guitar manufacturers like Martin & Guild are beginning to use scalloped bracing again because those older Martin guitars are the holy grail nowdays. They have a wonderful distinctive sound.
In the finest instruments, the top (soundboard) and braces are "voiced". The luthier listens to how the wood sounds when tapped and then shaves the braces until it sounds just right.
If you buy a guitar with scalloped bracing, follow the manufacturers recommendations about string gauges. Some scalloped braced guitars should NOT have Medium or Heavy Gauge strings installed because the braces can't handle the extra tension. If in doubt, use light gauge strings.
Scalloped Bracing Inside My Guild Guitar Looking Into the Soundhole.
Notice the curve upward going to the right where wood has been removed...
Bob, Gman ( o )==#