Le Grande Arche
Most steel string guitars use about 12 braces
for the top and 4 heavy braces for the back. These braces are absolutely
necessary to give the thin top and back enough strength to withstand
the 700N force from the strings.
Yamaha Guitar - Examples of bracing
Archtops only use 2 braces for the top
and no braces at all for the back. From the 700N string tension only
about 150N will be converted to down pressure on the Archtop Bridge. The
way the string force acts on an archtop top is completely different
from the way they act on steel string top. Two braces, a little arch
of about ¾” (19mm) and a thickness of the top of ¼”(6mm) is enough to
deal with the down pressure of 150N on the bridge.
Archtops are
inspired on the violin family, the sound post is skipped but the whole
concept is pretty much the same. A good example of natural evaluation. I
always have my doubt about the arched top on the . It
doesn’t give any structural advantage, it makes it much more expensive
to produce and maybe most important “it looks so dammed good!” The
picture shows the back of my Avant-garde top model archtop. Glossy,
shiny and arched.
