Tonewood is the term generally used to designate wood with recognized and consistent acoustic qualities when used in the making of musical instruments. The type of wood used on stringed instruments, such as a guitar, is a much debated factor contributing to its tone.
It is rare that a musical instrument is made entirely of a single kind of wood. Since sound is generated through vibration, the instrument's primary wood is selected for the particular characteristics of its vibration. In parts of the instrument not responsible for generating tone, woods are selected for other reasons: a hard wood for the fingerboard, an easily-worked wood for decoration, etc. No wood is inherently a "tonewood", the distinction is in the use of the wood.
There are a variety of different tonewoods to choose from. Below are descriptions of the general tonal properties of some of the most widely used tonewoods for acoustic guitar making. While it is possible to construct an acoustic guitar with a single tonewood, it is common to employ two different tonewoods: one variety for the back and sides, and one for the sounding board, or "top".
Back and sides
- Brazilian Rosewood (Dalbergia nigra), Brazil. Sometimes called "jacaranda", this species of genuine rosewood ranges in color from brick red to violet, with spidery black streaks known as spiderwebbing. The wood smells like roses when freshly cut. Brazilian rosewood is endangered and on the CITES convention list. Hence it is more costly and difficult to obtain than other tonewoods. It is extremely sonically reflective, producing full, deep basses and brilliant trebles. Brazilian rosewood is occasionally available in very limited quantities for custom or special limited edition instruments only. Brazilian rosewood harvested from stumps of areas which were cut years ago is available. However, this wood is almost always slab-cut which makes it more vulnerable to humidity and temperature changes. The grain patterns in stump wood is also very irregular, which adds to further instability. The Martin guitar company switched from Brazilian rosewood back and sides to Indian rosewood in 1969 due to higher prices and scarcer supplies. Several Martin guitars made in 1970 from Brazilian rosewood have been documented and are widely believed to be guitars started in 1969 but finished the following year.
- East Indian Rosewood (Dalbergia latifolia and Dalbergia sissoo) emcompasses 2 different species from India. East Indian rosewood is resinous, and generally more stable than most other rosewood species. Currently, the Indian government controls export of this timber. Dalbergia latifolia tends to be harvested from Tea plantations where it is used as a shade tree whereas Dalbergia sissoo is harvested from forested areas. Both are tonally similar being reflective and producing a deep warm projective bass response. Although latifolia and sisso can differ in appearance, distinguishing processed (i.e. sanded and lacquered) East Indian rosewood from Brazilian is difficult but not impossible. Brazilian rosewood can display distinct visual features not found on East Indian rosewood such as spiderwebbing.
- Dalbergia latifolia is typically richly grained with dark purple, red, and brown color.
- Dalbergia sissoo is similar to latifolia except the shades tend more towards red than purple. This species can also display crimson streaks in the wood.
- Genuine or Honduran Mahogany (Swietenia macrophylla) from South America. Yellowish brown to reddish brown in color, Genuine or "Amazon" mahogany is very stable. Mahogany is lighter in weight than rosewood, koa, or maple. In spite of its weight, mahogany yields a strong loud sound with a quick response and an emphasis on warm, round midrange.
- Figured Mahogany. This beautiful and rare (often quilted) variety of genuine mahogany occurs in a very small percentage of mahogany trees. Though more difficult to bend, figured mahogany shares the same tonal properties of the unfigured mahogany.
- Cuban Mahogany (Swietenia mahogani) from the Caribbean. Cuban mahogany is very similar to mahogany from mainland South America in appearance except it tends towards reddish brown in color. Cuban mahogany is denser than Swietenia macrophylla and the texture is much finer. Woodworkers often compare Cuban mahogany to silk and Honduran mahogany to burlap. The tone is similar to Honduran Mahogany with, some feel, a better treble response.
- European Flamed Maple (Acer campestre) from Germany. Curly, flamed, tiger-striped, or "Fiddleback" maple refers to the characteristic alternating hard and soft rippling which runs perpendicular to the grain in some rarer maple trees. This particular species of European maple is very hard and reflective, producing a loud powerful projective sound.
- Western Hard Rock Maple (Acer campestre) from Northern America. It is very similar to European maple, although the figure in the wood can be different. "Birdseye" maple is usually from Canada. After figured European maple became less available for the instrument-making industry, companies like Fender and Gibson started using more maple from Canada for their necks and tops. The difference between European (or Eastern) and Western maple can sometimes be identified by small streaks of minerals found only in European maple.
- Koa (Acacia koa) from Hawaii. Golden brown color with dark streaks and a lustrous sheen. Koa wood occasionally develops a curly or flamed figure. Regardless of any figuring, koa seems to have a bass response that is slightly less than that of rosewood and treble response that is slightly less than that of mahogany. The result is a very equally balanced instrument.
- Walnut. Imparts the bright "woody" tone of mahogany when played lightly, with much of the punchiness and power of rosewood when you dig in. When properly braced, a walnut-backed guitar can have a unique warmth and tonal depth. This is a dark brown, highly figured specialty wood which is grown in a wide variety of locations.
- Morado (Machaerium scleroxylon) from Bolivia. Also known as Bolivian or Santos "rosewood", or palisander, morado ranges in color from a light violet brown to reddish brown with occasional olive and black streaks. Finer in texture than most rosewoods, morado is a close visual substitute for East Indian rosewood, and has very similar tonal properties.
- Myrtlewood from North America. The best way to describe Myrtlewood is that it has the powerful voice of rosewood coupled with all the clarity, brightness and balance of maple. Myrtlewood can be found in the coastal mountain regions of northern California and southern Oregon. With coloration anywhere from an elegant whitish/straight grained look (a blonde mahogany), to yellow/green with flame, the tonal personality of Myrtlewood is consistent.
- Striped Ebony from New Guinea. Deeper and richer sounding than East Indian Rosewood, many would characterize striped ebony as very similar to Brazilian rosewood. It is dense, has similar reflective properties to Brazilian, and it also has a high specific gravity. It has a striking, distinctive vertical stripe pattern, variegated dark brown, black and green. It makes a truly exceptional twelve-string. Striped ebony comes from New Guinea, is exclusively government controlled, and is not an endangered species.
- Cherry (Prunus spp.). With a density and reflectivity approaching that of maple, cherry produces a rich, projective midrange and balance without favoring the bass or treble frequencies.
- Alder (Alnus spp.). It has a full and rich sound with a fat low end and nice cutting mids, and good overall warmth and sustain. It has less bite and lesser highs than ash. Alder is the most common body woods used by Fender Musical Instruments Corporation, and is usually found in Stratocasters.
- White Ash. It exhibits a "snappy" loud tone with a bright edge, but with a warm bass and long sustain. It is more aggressive sounding than alder. Ash is considered as the "traditional" Fender Telecaster body wood. The tonal character of ash is surprisingly loud and bright, with a strong midrange and a crisp bass. Ash is not used very often for acoustic guitars.
- Poplar (Populus spp.). One of the softer hardwoods, nicely resonant with a meaty tone. This wood is being used by many electric guitar manufacturers as a substitute for alder as it is quite similar in tone.
- Basswood. The principal wood used on most Japanese made instruments since it is the best available tonewood in Asia, although customer demand made the Japanese builders turn more to ash since 2004. It is a very light wood but it also isn't very sturdy and has no real grain. Its tonal response is very similar to alder.
- Sitka Spruce (Picea sitchensis) from North-West Canada & Alaska. Sitka spruce is the primary topwood for Martin and Gibson acoustic guitars. It is chosen because of its consistent quality as well as its straight uniform grain, longevity, and tensile strength. Tonally, Sitka spruce is extremely vibrant providing an ideal "diaphragm" for transmission of sound on any size and style of stringed instrument.
- Bear Claw Sitka Spruce. Not a separate species, but a relatively rare configuration of Sitka Spruce. The wood is randomly figured, due to genetic or environmental factors, to look like a bear has clawed across the grain of the wood. Once discarded by guitar manufacturers, this particular variety is now highly coveted for its unique patterns. From the Pacific Northwest.
- Engelmann Spruce (Picea engelmannii) from North America. Engelmann spruce is prized for its similarity in color to European (German) White spruce as well as its extreme lightness in weight which seems to produce a slightly louder and more projective or "open" sound than Sitka spruce. Engelmann spruce grows in the alpine elevations of the American Rocky Mountains and the Pacific Cascades. It is considerably more limited in supply than Sitka spruce, and therefore mainly used for top of the range acoustic guitars, such as in Yamaha's highest offerings.
- Adirondack Spruce aka Red Spruce. This legendary wood that Martin used for its tops throughout its golden years came from the East Coast, from the Southern Mountains into New England and upper New York State. Called both Appalachian and Adirondack spruce, it has a creamy white color. Similar to Sitka, Adirondack responds well to either a light or firm touch. It has more overall resonance than Sitka. Interesting grain color variations make this another visually desirable top. Adirondack has been unavailable since the mid-1940s. Virgin growth has been (fortunately) preserved in national parks; the rest is all second growth, plentiful but too small to be usable for guitar tops until recently. Guitar makers have started finding second growth of at least 100 years old that is big enough to be used for tops again. Adirondack is, like Alpine spruce, very expensive and mainly used for top of the range acoustic guitars.
- German Spruce from Europe. The "ringiest" of all spruce species. Extremely clear and bell like, with the versatility of Sitka. Exceptional sound for light to very firm techniques. Very white in color.
- Western Red Cedar (Thuja plicata) from Western Canada and the Pacific Northwest of the United States. Western Red Cedar has long been used as a soundboard material by classical guitar makers for its vibrance and clarity of sound. It is extremely light in weight compared to spruce, and the tonal result is generally a slightly louder, more open response. Balanced, warm and rich with bright trebles. What is most characteristic of Red Cedar is that it sounds broken-in, even when new. Exceptional sound for light to very firm techniques. Coloration runs from light (almost as light as Sitka) to a very dark reddish-brown.
- Redwood from North America. It has more richness in the bass than cedar. Redwood responds to subtle playing with a crisp balanced sound. The bass response is particularly round and full with a piano-like crispness. Lacquer and glue do not bond quite as well as the spruces. Because of this (as with cedar), some Luthiers (Goodall) recommend light gauge strings only on guitars with these tops. Originally from Northern California, many luthiers (i.e. Breedlove) get redwood from recycled lumber and timber salvage.
- Western Larch (Larix occidentalis) from North America. Western larch has clearly marked annual rings and a fine uniform texture. Larch is harder and stronger than most conifers including spruce. It bears a close visual resemblance to Sitka spruce and due to its increased stiffness, it is an appropriate choice for scalloped braced models yielding a projective and crisp response.
- Koa (Acacia koa) from Hawaii. Historically, koa tops have appeared primarily on small bodied Hawaiian guitars and ukuleles, although recent koa dreadnoughts and custom guitars have been popular. Koa produces a predominately bright treble response with less volume than spruce, but the slight loss in volume is overshadowed by the extreme beauty of the grain. Koa tops are available on special order and custom instruments.
- Genuine Mahogany (Swietenia macrophylla) from Brazil. Mahogany was first introduced as a topwood in 1922 on the lesser expensive guitars. Tonally, mahogany is less projective than spruce, producing a subdued response that is crisp and delicate with emphasis on the midrange. Mahogany tops are usually available only custom instruments, but has recently become a standard top in the Baby
- Walnut (Juglans spp.). Using a highly figured walnut for a top wood, matched with walnut back and sides, was a first of the Breedlove company but is now offered by Taylor Guitars and others. Rich, warm bass with plenty of crispness on the mid and treble side is typical of an all-walnut guitar. Walnut offers the beauty and visual impact of an all-koa guitar, but at a much lower price. Coloration is dark brown with a lot of figure and flame.