Guitars, like people, come in all shapes, sizes and colors. Also much like people, when you look beneath the surface, they’re all made of the same stuff: In this case, wood, metal, plastic and curves.
For all the bewildering variation you may encounter in the wide world of guitars, there are but a manageable handful of variables that have a significant effect on tone. Because of this, getting deeply familiar with the basic anatomy of a guitar can simplify choices in the very best sense.
But getting to know what guitars are made of can have the opposite effect as well: You may some day find yourself playing two instruments that look similar but sound and feel like different beasts. Knowing what a guitar is made of can enhance your appreciation of the subtle differences that give each instrument its personality. In this way, a little knowledge around the anatomy of a guitar can also make the world of tone seem more complex, more interesting and engaging.
The Body: Wood Shapes Tone
Although it seems intuitive that wood could be a major factor in the sound of an acoustic instrument, people are often surprised to some to find out that the cut of wood that goes into an electric guitar can have a significant impact on its tone.
The strings of an electric don’t put out very much sound until you hook up to an amplifier, but even in the face of this limited acoustic power, the wood body of a guitar certainly shapes the way those strings vibrate. Different types of wood accentuate different frequencies and play a role in increasing either sustain or “snap.” These are differences that can be measured and heard blind. And most of it comes down to finding a workable balance between mass, density and rigidity.
The majority of high-quality Fender electrics are made from Alder, a popular North American tonewood. It’s lightweight, but also fairly stiff and rigid, with tight pores that run in long, slightly curving lines. Historically, it’s one of the most popular tonewoods for electrics with “bolt-on” necks, and its tone contributes the bright, tight sound of many Fender-style guitars.
But alder isn’t the only wood used for the body of these instruments. Only slightly more expensive are guitars made from the “Swamp Ash” of the eastern and central United States. These trees (not to be confused with the harder “northern” ash) grow well in humid regions and have developed a strong, rigid structure that’s interspersed with enormous, soft and open pores, arranged in a swirling grain pattern.
When compared to alder, guitars made from a good cut of “southern” ash might sound just a bit smoother and more open, with a bell-like top end, and supple lows. It’s a bit more “creamy” and resonant, but gone is a bit of alder’s authoritative bark and spunky bite, thanks to some subtle filtering of midrange frequencies.
Cheaper (and perhaps less visually appealing) than either of these is Basswood. Its extreme light weight, small pores and soft texture conspire to soften both the highest highs and the lowest lows, making it more midrangey and forward than alder, although with a slightly more subdued upper mids and top-end.
These woods may do just fine for Fender-style guitars with bolt-on necks, but “set-neck” electrics of the Gibson style are most often made out of a tonewood with some of the softest top-end around: Mahogany.
Mahogany is an open-pored wood, like swamp ash, but unlike swamp ash, its structure and density is fairly uniform. This leads to great sustain, slightly compressed mids and a dark upper-register, making it one of the thickest-sounding foundations available. It’s also beautiful looking wood in its own right, ranging in color from light mocha to deep chocolate when finished.
There are plenty of guitars that are made from solid mahogany and nothing but: Gibson SGs and the Les Paul Custom and “Studio” models (ironically not often the best pick as a default Les Paul to have in the studio) are particularly dark and throaty thanks in large part to their all-mahogany construction.
To compensate for this dark character, many Les Pauls, PRS guitars, and other luxury models add a thin piece of Hard Maple as a “cap”, which covers the entire face of the guitar.
Maple is not only an attractive wood (it often contains eye-catching natural “flame” patterns) but it can significantly alter the tone as well. Although this cap is rarely over 1/2” thick, it’s extremely hard and massive, adding plenty of sparkling highs and assertive upper midrange articulation to what might otherwise be a thick, almost murky-sounding instrument.
Makers of acoustic guitars often take a similar approach. Here, the most common wood for the face or “soundboard” is Spruce, which is stiff and bright. Meanwhile, the back and sides of an acoustic will often be made of mahogany, such as with the Gibson J45. Rosewood is another common choice for back and sides, and it’s found in acoustic guitars like the Martin D28 and D35. Although rosewood may be slightly more expensive, its added weight and rigidity provide tight, deep lows and a shimmering top end that can make a mahogany-backed acoustic sound dusty and homespun by comparison.
On classical guitars, rosewood is a common choice for the body, while the top is often made out of cedar, which which has some of the properties of spruce with a bit of a darker tone. You’ll occasionally find more exotic woods used in acoustics, such as Koa or Walnut, and now and then you may find an acoustic with tight, bright-sounding maple back sides – such as the Gibson J-200 or the Taylor 610.
Check Your Neck: Construction and Fingerboards
The wood of the body isn’t the only part that matters. Neck woods can have a significant impact as well. Fender-style guitars have a “bolt-on” neck, meaning it’s literally screwed onto the body. The neck itself is often made of maple, which is one of the strongest woods around, contributing to the tank-like resiliency of these guitars. It also contributes to the tone: The sheer mass and rigidity of maple, along with the bolt-on construction, limits sustain, adding to the percussive, snappy sound of this type of guitar.