Observations on Top Bracing
Since my kit’s guitar top died the death of a thousand dry climates I have to re-create the top piece (I’ve already mentioned that, I know). But as I was studying up on the bracing I kept running into the arc that is on the bottom of the X-brace. I kept wondering, “But do I need a radiased dish to place the top into?” And the answer? No. The reason is this: the bracing material is flexible and as the luthier shapes the pieces to the brace template the slight curve will be small enough [12' to 30' radius] that the go bar deck [which is another topic for discussion] will press the flexible braces down to the flat top and when the go-bars are removed the slight curvature of the braces will be picked up by the whole top. This creates tension for resonance as well as creating a shape that (as I understand it) will direct the sound internal to the acoustic guitar through the sound hole.
Bracing is amazing to me from an engineering perspective. My dad was a civil engineer (now a pastor, the past tense is not to indicate his passing) and so I grew up with some moderate exposure to things like structural engineering and since we lived in Nevada and California earthquakes were part of that discussion. The whole point of bracing is to keep the wood in tact as it handles the abuses thrown at the guitar body parts. This isn’t a surprise, but it’s important to recognize it’s job is to handle vibration and keep it down. Except that the top and back make more awesome sounds when the (right) vibration is up! So, bracing is rather interesting because the patterns that are out there help structurally, but do impact tone and resonance. I’m not an expert on bracing yet, but I do hope to become one.