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Tone Tip: Acoustic Tonewoods

Dave Hunter | 09.10.2008

1937 L-00I have focused a lot of scrutiny in past installments of Gibson Tone Tips on the woods used to construct electric guitars, but this time out let’s shine the light on a breed of instrument where you can really hear the wood at work: the acoustic flat-top guitar. Wood type and body shape/style really are the determining factors in the voice of any flat-top, all of which coalesce successfully or otherwise according to the skill with which the construction has been rendered, with some significant influence from other factors such as the type and pattern of the top bracing. For this discussion I’m considering only guitars made entirely from solid woods, meaning there’s no laminated or plywood in the top, back, or sides.

The majority of any flat-top’s tonal character is produced by the top of the guitar (also called the soundboard), although the wood used for the back and sides—and even the neck and fingerboard, to some extent—also contribute to its sound. Spruce is the most traditional wood for flat-top soundboards. It’s a strong, light, straight-grained wood with a sweet, well-rounded voice and a good high-end response. Different varieties of spruce are used in guitar-making, the most common being Sitka spruce, which leans a bit toward a brighter tonality when compared to the rarer Englemann spruce, for example, which is often heard to be a bit mellower and warmer. Adirondack spruce from upstate New York is also used in some up-market models, such as Gibson’s Legends Series 1937 L-00. This scarce, costly wood is known for its rich, mature, and well-balanced voice, and is considered a deluxe option by makers that use it.

Another popular, although lesser-used, top wood is cedar, generally acquired as western red cedar. This is a slightly softer wood than spruce, with a somewhat darker hue to it, but it still has an excellent strength-to-flexibility ratio. Cedar has been a favorite top wood for nylon-string classical guitars for years, but is preferred by some steel-string flat-top players too, especially when its slightly warmer, smoother sound and easy, immediate response suit the music and the playing style. All quality tonewoods used in acoustic guitar making require some breaking in—a playing-in period—and as a result, the guitars made with them will improve some with age and use. Cedar, however, seems to need less playing-in than some other woods, and expresses something closer to its ultimate voice a little earlier in the guitar’s life. You’ll find a solid cedar top on the Epiphone Masterbilt EF-500RCCE steel string and EN-546CE classical. Some makers have also used solid mahogany in their soundboards, usually in lower-tier models which tend to have mahogany backs and sides too, and koa has occasionally been employed as well, particularly in Hawaiian-style acoustic instruments intended to be played on the lap with a steel slide.

Rosewood is often thought of as the king of tonewood for back and sides, and it contributes to a deep, full voice with bountiful warmth and dimension. It’s probably fair to say that, for some guitarists, its rich red-brown color and appealing grain are almost as desirable as its tonal properties, and it has generally been considered a wood of middle and upper-tier instruments. Some big bodied flat-tops that generate enough of these sonics from their top woods and constructional factors, however, might not require the added depth that rosewood provides, and in fact might be better served with mahogany backs and sides. A more affordable wood, mahogany’s bright, tight sound and excellent presence make it a fantastic choice, regardless of cost, for plenty of guitar designs. Lesser seen in the work of other makers, but a staple of big-bodied Gibson flat-tops in particular, maple offers a voice that is bright, full, and cutting, with great projection and sustain. This is the wood of the back and sides of the best known of Gibson’s mighty SJ-200 True Vintage, or J-185 True Vintage, classic front-of-stage flat-top for rhythm work and big, cutting riffs. Render the same design with rosewood back and sides, as with the SJ-300 Rosewood Modern Classic, and you up the richness and depth, while maintaining excellent volume and projection.

There’s a cornucopia of tonewoods out there to test and taste. Check out the range of combinations available, and you’ll be amazed at how the voices of different guitars can vary accordingly.