While tonewoods get lots of attention, and rightfully so, many players overlook how bracing affects the sound of an acoustic guitar.
The acoustic guitar’s top plays a big role in creating your sound. Much like a speaker cone, your guitar top is essentially pumping the air — turning vibrations from the strings into pressure waves that eventually reach your ears. If you strum a chord on your acoustic and press down on the top, stopping the main engine, you will hear this for yourself.
The bracing on your soundboard helps control the manner in which it vibrates. A guitar top without bracing would vibrate chaotically, and wouldn’t produce the rich, warm tone you’re looking for. The bracing shapes the way a top will vibrate and gives the guitar its voice.
This is really important! It’s what makes a Guild sound like a Guild or a Breedlove sound like a Breedlove! Subtle differences in bracing can affect a guitar’s voice as much or more than the wood it’s crafted from. Many luthiers spend hours fine tuning their bracing, shaving and sanding each piece to produce a design that really allows the top to resonate in just the right way.
Let’s look at the most common bracing patterns. Note that many guitar manufacturers have their own unique version of the designs.
Ladder bracing is simple and old school, with straight bars reinforcing the soundboard. Many old guitars, and I mean really old, have ladder bracing. Before luthiers really understood what was possible, they needed a way to support the tension placed on the soundboard by the strings. Ladder bracing was an obvious solution, but it was also problematic: Ladder-braced tops rarely lasted more than five years before they warped and had to be thrown away.
Some players associate the “boxy” sound of ladder bracing with old blues recordings and, in an effort to emulate that sound, will look for a guitar with that bracing. Ladder bracing is still the standard for traditional archtop guitars, as their thicker tops don’t need the extra support and benefit from the extra freedom to vibrate.
X Pattern Bracing
Today, the standard “X” shaped bracing pattern is by far the most common for steel string guitars. It was invented by Martin in the 1920s, and it creates a classic sound. There are many variations on the “X” pattern, but visually the X will stand out in most designs. There is a lot of debate among luthiers on the advantages of various forms of X bracing. For a more detailed look at Martin’s bracing patterns click here.
Classical and other nylon stringed guitars will most often use fan bracing. Because the nylon strings create less tension, less support is needed in bracing the soundboard. This allows luthiers to use a lighter bracing style and a thinner top as well. Fan bracing on a steel stringed instrument just wouldn’t provide the necessary support.
Hybrid Bracing Patterns
Jean Larrivee was one of the first luthiers to try combining Martin’s X bracing pattern with the fan bracing patterns of nylon string guitars. The design uses an elongated X and tone bars running at about a 45 degree angle. Today a much refined version of this bracing pattern is used to create their distinctive sound. Hybrid bracing is also used in many higher end PRS acoustics.
Regardless of the pattern, many custom guitars feature scalloped bracing — a design in which the wood is scooped out near the ends of the brace. By scalloping the braces and removing excess material, each brace still provides the necessary support while allowing the top to vibrate more freely. In turn, this allows for larger frequencies to escape the sound hole and produce more low end.
If you’re in the market for an acoustic guitar, it’s helpful to know the basics of how these instruments work. While you may like the sound of a maple guitar, each brand will have a unique voice, even when the same tonewoods are used.
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