Since the beginning of time (we do not count time before guitars were invented!), builders and players have argued about which bracing scheme produces the loudest and most balanced tone. To this day, one can readily find threads on on-line forums with topics like “Shaving Braces for better sound”, “X-bracing vs. Fan bracing” etc.. In developing RainSongs we were forced to research this issue in deciding how to construct our instruments.
The first generation of RainSongs (1995 – 1998) were built using the popular X-bracing (steel strings) and fan bracing (nylon strings) schemes, the braces being constructed out of carbon (of course!). While these instruments had exceptional plugged-in sound, we wanted to pursue a louder acoustic sound with a fuller bass response. Our efforts to make the bracing lighter resulted in marginal improvement. So it was back to the drawing board to evaluate the role of bracing in guitar soundboards and to find a solution that took advantage of the unique materials that we used to build our guitars.
The sound-box of a guitar functions similar to a stereo speaker, the soundboard being analogous to the cone of the speaker. For the best sound, the speaker cone needs to be light and stiff. Wooden guitar builders have always known that thinner and lighter soundboards made of solid wood tend to produce the loudest and most resonant instruments. But thin sheets of wood by themselves possess neither the stiffness necessary to sustain vibrations nor the strength to support string tension. Enter bracing.
The purpose of bracing is to provide soundboards stiffness and strength. The challenge is to balance the required stiffness and strength with the weight of the braces themselves. The bracing pattern needs to cover enough surface area on the soundboard so that the entire soundboard is stiff. The braces need to be strong enough to handle the string tension. However, the weight of the braces need to be minimized to keep the soundboard from being “overbuilt” and hence dead sounding. The pursuit of these conflicting goals have lead to several empirically derived bracing patterns over the years. While treading the fine line between excellent sound and imploding soundboards, guitar builders tend to slightly overbuild soundboards to be on the safe side. The practice of “shaving” braces leads to better sound due to reduced bracing weight, until the strength of the bracing system is compromised … at which time the soundboard cracks. In steel string guitars, the X-bracing scheme is widely accepted as the best compromise for effectively transmitting string vibration energy from the bridge to most locations on the soundboard while adding the minimum amount of weight to the system. However, the fact remains that this is still a “compromise”.
Ideally, a guitar soundboard would be stiff over the entire surface, strong enough to handle string tension and yet be light enough to result in a sonically responsive system. In 1999, RainSong invented Projection Tuned LayeringTM
, a patented process that took advantage of composite materials to achieve these goals while completely eliminating Projection Tuned LayeringTM
bracing. Carbon fiber is a very light material that weight-for-weight is stronger than steel. uses minimal amounts of Carbon Fiber and other composite materials to produce a soundboard that is stiff across the entire soundboard surface. String vibration energy is transmitted over the entire sounboard surface, as opposed to being transmitted along braces to locally stiff areas of the soundboard. Moreover, RainSong soundboards weigh a small fraction of a braced wooden soundboard. The result, a guitar with greater acoustic volume and clean, detailed tone.
Our experience at RainSong has shown us that the correct question is not “Which Bracing Pattern?” but “To Brace or Not To Brace?” And the answer to this question is abundantly clear. Projection Tuned LayeringTM accomplishes the ultimate purpose that bracing systems were designed to but not completely able to achieve – a uniformly stiff, strong and light soundboard.