Lighter Bracing For A Bigger Sound
The inspiration for my new modified X-brace system came from noticing the steel girders on a bridge during a drive through the Texas hill country. The beams supporting the structure had holes in them!
As luck would have it, one of my clients at the time was an engineer employed by the state to design bridges. In answer to my questions, he gave me a quick lesson in how structural beams work. He briefly explained the theory of beam deflection, and how the support beams do their job.
The structure ensuring the integrity of the bridge must be both strong and light. The holes in the beams reduce their weight -- without changing their strength! Naturally, this increases their strength-to-weight ratio. A little research confirmed that this concept is basic in the design of support structures where weight is important -- aircraft construction, bridges, race cars, bicycles, and roofs to cover large areas.
Five or six years ago, I built a first experimental guitar in which I applied this theory to the bracing system. First, I took a standard fan brace, placed it between two supports, and hung a weight from its center. I measured the deflection in the brace caused by the weight.
Then I started drilling holes in the brace, in patterns based on those of the support systems I'd been studying. After drilling each hole, I put the weight back on, and measured again. In this way, I was able to determine when the deflection increased, showing that the brace was becoming weaker. Finally, I made a dreadnaught, and drilled patterns of holes in all but the two fingerboard braces.
A few weeks later, as I put strings on the guitar for the first time, I wondered if I had done something really stupid.
But to my amazement, the instrument was fabulous! It performed just as I had hoped and expected. Lightening the structure caused the soundboard to move with less applied energy, and to move for a longer time -- without affecting its strength! This causes the instrument to have more volume and sustain than it would have with ordinary bracing.
I kept that guitar for a year, to monitor its ability to withstand string tension. At the end of that year, it showed no signs of any failure in structural integrity, and it has remained stable to this day. The sound of this guitar still impresses those who hear it. It is owned by a man in Killeen, Texas, and I still see it often.
Since building that prototype, I have spent many hours developing and refining the process. I've also enlisted the aid of some "smart friends". One of them, Dr. Woods, is a teacher of math and physics at the University of Texas, who had worked in a nearby guitar factory to satisfy his curiosity about how guitars work. When I told him of my idea, he agreed that the result would be an instrument that is more sensitive to string vibration, and that the vibrations would decay more slowly.
Guitars made with this technique literally "speak for themselves". Since I made it available as an option in October, 2000, almost every client who has had the chance to hear one of these instruments has asked me to use the modified X-bracing on their new guitar.
In such a traditional craft as mine, it's risky to do something new and a bit different. Some may think it's "just a gimmick". But this bracing system is based, not only on sound scientific principles, but on years of experience with many different kinds of structural supports.
Does it work on guitars?
Take the time to listen to one of these guitars, and let your ears be the judge.