The Role of Wood in Guitar Construction
By William Lewis
When it comes to guitars, there are a ton of variables when tone is concerned. You have pickups,
strings, picks, cables, tubes, amps, speakers, EQ, etc. All of those are very important when it
comes to your tone and should not be overlooked. There is one thing, however, I feel is often
overlooked when choosing a guitar. I have time and time again heard a player say, “This guitar just
isn’t doing it for me. I’ve changed the pickups and strings and it still just isn’t right.”
While it may be true that a guitar just won’t suit some players no matter what changes that player makes, there is an even more important thing that you must consider before you buy a guitar. Something that determines the tone of the instrument before a pickup is even set into the body. That determining factor is the wood the instrument is constructed of. Every wood is different in terms of weight and tonal character and that has an impact on your tone.
Adding a top wood onto a guitar can even have an affect on the overall tone of the instrument. The fretboard material, or lack of material, will also come into play. It can be very confusing trying to sort it all out. But, the more you know about your potential purchase, the happier you’ll be with your new guitar.
I’m going to cover a lot of information in this article. I’m going to cover the different types of woods, the tone of the wood, different figuring (spalted, flame, quilted, burled, etc.), the difference between a top and a veneer, and other relevant information to the topic. Let’s start with a general overview of the different woods.
There are two main types of Maple in the guitar world. One would be Hard Maple (Acer saccharum), the other Western, AKA Soft Maple (Acer macrophyllum). As you would imagine, the Hard Maple would rate at about a 10 on the scale. It’s the brightest wood you can get for a guitar. The Soft Maple would rate about an 8 or so. It’s bright, but not so much as hard.
Hard Maple is what you find in guitar necks. Soft Maple is used for bodies and tops only. It does not have the structural integrity to be used as a neck material. Both are rather easy to finish and work well with a variety of finishes.
Basswood — Tilia americana
Basswood is a lightweight wood that would rate about a 4 on the scale. It really has a strong midrange tone, which is why guitarists such as Joe Satriani, Steve Vai, and others like basswood bodied guitars so much. It allows you to be heard in a band setting. Even though Basswood is closed grain, it takes a lot of finish in. It’s also quite soft, so a good polyurethane finish is best to protect the wood from damage. It really has no defining figure, aside from the occasional mineral streaks of red, black, or green.
It is found from Maine to Minnesota and down south to West Virginia and Iowa. If you’re so inclined, you can actually eat the leaves from this tree.
Walnut — Juglans nigra
Walnut is found from Canada down into Texas. It’s also known by the name Black Walnut as well. It has also been grown in Europe, under more controlled conditions for its wood. It is an open grained wood. You typically see this wood either finished in an oil based finish, such as tung oil, or a clear gloss or satin. The color and figuring of this wood is very nice. If you wanted a solid color, you might go with either Hard Ash or Soft Maple, as they don’t have nearly attractive a grain and the tone of walnut would be right between those two.
Walnut is brighter sounding, 7 on the scale. It’s bright, but not like Hard Maple. It also tends to be a bit lighter too, even though it’s a heavy on the wood scale.
With Rosewood, we’re looking at the same situation as with mahogany. There is a genuine genus and others that aren’t. I’m going to cover a few of those here.
Dalbergia baronii — Madagascar Rosewood. Threatened by habitat loss and is on the Red List of Endangered Species.
Dalbergia latifolia — East Indian Rosewood. Grown in India, but illegal to export wild grown due to rarity. It is very highly prized for it’s strength and high density, but that also lends to its cost. Since it is grown in limited quantities due to slow growth and in plantations, supply is low while demand remains high. This is typically the wood you see in bodies. It is oily, which is hard to finish. It is typically a clear finish due to the natural beauty of the wood. It is also very heavy and many players will chamber the body. It rates at about a 2 on the scale. It’s similar to mahogany, but with a smoother treble response.
Dalbergia nigra — Brazillian Rosewood. This particular species of rosewood has nicer figuring than others in its genus. However, since 1992 it has been illegal for trade. What this means is nothing after the date of the trade ban is legal. However, any wood harvested before that time with correct documentation is legal for trade, but highly expensive.
Dalbergia melanoxylon — Grenadilla. This type of rosewood is not yet endangered, but due to low germination and poor conservation, supplies are dwindling. No word yet about possible trade restrictions. Gibson started using this type of rosewood for their guitars around 2010.
Alder — Species Alnus rubra - AKA Red Alder
Alder is most commonly seen in the Northwestern US. This particular species is the largest of the alder trees in North America. Most of you likely know alder from Fender guitars. I was actually able to email Fender about when they switched to alder and why. Leo simply was attempting to keep costs down when he made the switch to alder from ash. Ash takes a lot more time to finish because it is an open grain wood.
Alder would sit at about a 5 on a scale of warm to bright. It’s not overly bright, nor is it overly warm. It has a very balanced tone when we consider the bass, middle, and treble characteristics of the wood. This wood also grants a bit more room in choosing of pickups, as you can use a bassy pickup and it won’t be overbearing. Contrasting that, you can go with a brighter pickup and still have it sound good. Alder is a closed grain wood, meaning it is very easy and quick to finish. Typically, alder is seen with a solid finish. There really isn’t much in the way of figuring on this type of wood so a natural finish would be very plain. While that isn’t a bad thing, most manufacturers simply go with a solid color.
There are a few different types of mahogany to go over here. Each one is fairly similar in tone to the other, but it’s important to note each since different ones are used. However, their tone and finishing stays the same with each species. There are three species in the genus Swietenia and these are considered the true mahogany woods. I’ve listed these three below.
Swietenia mahagoni — species of mahogany found in Florida, Jamaica, Cuba, The Bahamas, and other areas in the Caribbean Sea area. It is actually protected in Florida and from my studies is said to be the species where mahogany originally was sourced from. This species was used in the 1500s for both ships and furniture, as well as other uses in instruments of the period. This wood is covered under the Lacey Act as well, meaning its history must be documented. This species is rare due to past harvesting. It is rare to see this in a modern guitar body due it its protections and rarity. It’s also not seen because of the paper trail that would be required of the instrument.
Swietenia macrophylla — species of mahogany found in Central and South America. You could find this species in Peru, Mexico, Honduras, and Brazil. This species falls under a few different names. You might have heard of Honduran Mahogany and this is the exact same thing. One very important thing to note is that in its native environments it is protected. It may be permitted to be grown on a farm, but I haven’t turned up any evidence of that. The interesting thing to note is that this species is still used in most mahogany trade today. How? Plantations. This species has been transplanted into Asian countries, including India, Fiji, and the Philippines. By growing it here, the plant can grow as it would in its native environment, but trade is not restricted. Most mahogany today comes from sources such as these.
Swietenia humilis — this is the smallest mahogany species out of the three species of the Swietenia genus. It is typically found in Central America, stretching from Mexico to El Salvador. It is protected, but not entirely illegal to use in a production sense. It’s interesting to note that this species has been used for medicinal purposes and also has a poison in the seeds and bark as well.
Out of those, only one is really used by most manufacturers. The Honduran mahogany is the likeliest one, being that it is cultivated in areas of the Pacific. Humilis may be used, but I haven’t been able to turn up any evidence of that. Mahagoni isn’t used because it would be too costly given the rarity and the Lacey Act adds a further complication as well.
There is one further species of mahogany that is seen today in guitar construction and it is still freely traded on the open market:
African Mahogany — Species khaya ivorensis. It is one of the few woods considered to be a mahogany without being in the Swietenia genus. This species is endangered by habitat loss, so it may very well be placed on a protected list in the future. For now however, it is openly traded. I’v e seen nothing that hints at restriction yet, but it’s worth mentioning because one day it will likely be restricted.
The following is an umbrella of mahogany in general. There simply isn’t enough difference in each to warrant different descriptions and the species we see today are indeed nearly identical in both grain type, weight, and tone.
Mahogany would fall at about a 2 or so on the tone scale. It’s very warm and that makes the wood sound very rich. It shares the same easy-to-finish type of grain that alder has, making it easy for manufacturers. Where mahogany is slightly different though is that in addition to being easy to finish, it’s also a wood you can put a clear or transparent finish one. Mahogany has a nice brown color that looks very nice when finished in a clear gloss or satin. With a transparent finish, the mahogany has a nice wood grain that looks very good with basic transparent colors. Colors such as light blue, red, blonde, yellow, and light green look very nice on mahogany.
We have two main types of ash, Northern Hard and Swamp.
Northern Hard (Species fraxinus americana) is found in the Eastern half of the US and extends up into Nova Scotia. It is very hard and quite dense. It is an open grain wood and requires more time to finish as well as more finish to fill in the pores.
Swamp ash (Species fraxinus pennsylvanica) is actually located in the same places you would find Northern Hard ash, and is practically identical. This is rather confusing, as you might be wondering why two different names for the same wood? Swamp ash is actually a rare name for the wood. It’s more commonly known as Green or Red ash. Swamp ash is referring to ash pulled out from the water of a swamp. This yields a lighter wood due to its more porous nature. It, like Northern Hard ash, is difficult to finish.
Both species look very good with a clear or transparent finish due to the nice grain of the wood. Northern Hard would be about a 7 or so on our scale of warm/bright while Green Ash would be about a 6 or so. Swamp ash is a little less bright than the Hard simply due to it being more porous in nature, allowing for a lighter wood. Ash is just a bit brighter than alder overall.
Flamed maple figuring comes from a distortion of the wood fibers. Sometimes you might hear that the flame comes from the grain. This isn’t true. Usually, the flame is perpendicular to the grain of the wood. A flame figure occurs in other woods as well, such as koa and walnut, but is most common in maple.
Quilted maple comes from an actual grain distortion. It’s seen when you flat saw a particular piece. Quilted pieces tend to cost more than flamed maple piece. Quilted pieces of high quality are rare and reserved for more expensive guitars. Most of your cheaper guitars that offer a quilt will simply be a veneer, not an actual piece. Nothing at all is wrong with a veneer, but it won’t have the tonal impact of an actual top.
Burled maple comes from the Acer Saccharum (aka sugar maple). This figuring comes from a tree that has undergone a lot of stress. The stress can take the form of mold or insect invasion, an injury to the tree in some form, a virus, or even certain types of fungus. You might have seen a tree with a burl if you’ve ever seen a tree that had a trunk that looked ballooned out. That is one sign of a burl. A good bit of burls are found under the ground. So you wouldn’t see those until the tree falls over due to nature or man.
Burled wood is expensive due to rarity and it’s look. People like how it looks, there isn’t a huge supply, and that drives the price up. It’s also hard to work with since the grain is usually not uniform in one direction. So care must be taken so it doesn’t chip or break. Redwood trees also have burls, but these are far harder to get given the size of the trees. One last type of burl that usually isn’t seen in guitars is from the Padauk tree. It, like the others, is rare and is seen more in furniture and veneers.
Birdseye and burl are often confused with each other. Birdseye differs in two ways. One is that the birdseye lacks the knots that you find in burled wood. Two, the cause of the figuring is as of right now undecided. It is likely due to the specific area the tree is found. Anomolies in the soil or water, a specific virus or fungus, or even a genetic mutation. This figuring is common in two areas of the US, the Great Lakes and smaller areas of the Rocky Mountains.
Spalted woods come typically from a fungus. The trees do not have to be dead or dying for this to occur, as living trees have been found to contain a spalting in them. However, it is more common to find it in a dead or dying tree. Unlike other figures, there are three things that can be included into the definition of a spalted wood.
One thing is the coloration of the wood, called pigmentation. This is caused by the invasive fungus changing the color of the wood. The color depends on the concentration of the invasive colony in that area. White rot is when the fungus consumes lignin. This makes the wood more porous and light. This is the opposite of the crumbling brown rot that has a bad smell and is really worthless in wood in terms of guitar manufacture. Both pigmentation and white rot weaken the wood.
The final characteristic is zone lines. These are interesting because these are typically lines of defense set up by the fungus to protect what it has found. It may also simply be a fungus just outlining its position. This characteristic doesn’t weaken the wood, unlike the other two. The fungus causing it does, however.
The conditions that allow spalting to happen are fairly uniform. The wood must be slightly saturated with water, 15% up to about 20%. Too much water will not allow a fungus to grow, so woods submerged in water will not see this occur. Typically, these fungus like warmer weather. Warmer weather allows for faster growth of the colony, with faster growth between about 70 and 90 degrees Fahrenheit. One single type of fungus in a wood will often spalt it faster than having two or more colonies in the same wood. The reason for this is because one can go about unrestricted, but add in more colonies and they will begin to notice the other and concentrate on that fungus as well.
Difference between solid top and veneer
Most cheaper guitars out there use a veneer on top if they have a figured top. What that means is that instead of an actual substantial piece, they cut the wood very thin. This gives the guitar a nice appearance, but doesn’t impact the tone enough you hear. An actual wood top can vary from 1/4“ to about 1/2“ thick. This will have an effect on the tone that is enough to hear. Really, a veneer isn’t a bad thing to have. It’s not like fake photo top. A veneer is a real piece, just cut very thin for cost purposes.
Types of finish
Today, we typically see a couple of different kinds of finishes. Most common on instruments today is the standard polyurethane finish. Poly finishes are easy to apply, making them a staple in the industry today. Some companies even put the actual color in between the layers of clear coat. That gives the color some dimension. It more often than not has a gloss top coat. Sometimes you do find a satin finish, more typically on acoustic guitars. I’ve seen a few Schecter guitars that use a satin finish and most custom shops offer this as an option. Polyester is used on cheaper guitars because it is even cheaper than polyurethane. It is a resin based finish, so it’s very deadening to the tone of the guitar. This may be why people have a prejudice against agathis wood, most of those guitars are low end and use a polyester finish.
You also have nitrocellulose, which is a plant based finish. Nitro is much thinner than a poly finish and it doesn’t gum up the wood pores. It can be either polished or in a satin type look. It is often said to be better than a poly finish.
The whole debate over finish comes down to one thing, the thickness of that finish. If a thinner poly were used, the guitar in turn would have a more resonant tone. This is really the heart of that debate. Nitro isn’t better, it’s simply applied in a better way by being a thinner finish. If poly were applied thinner, it’s likely this debate would be moot.
Nitro is more easily repaired though. Poly is repairable, but the process is a bit more involved. I’ve heard a myth that it’s not. It simply takes a skilled repair person to do so. The real tone killer on a guitar is the filler that is added to hide the wood seams. That will deaden the tone like nothing else.
I’ve done fairly extensive research about the different materials used in guitar hardware. Between chrome, nickel, black power coating, black nickel, and gold there really is no discernable difference in tone. I actually posed this question to Gibson, Fender, Ibanez, and Warmoth along with my own research. Each company said that the tone is, if anything, affected in such a small way as to be unnoticeable given other tonal characteristics of the guitar. My research has said that it would only be a factor if the hardware were made entirely of the metal in question. So if a bridge were solid gold or nickel instead of a plated material it would have a more pronounced affect.
That brings me to the Floyd Rose blocks. If you haven’t seen these, they are solid pieces of aluminum or titanium. These do in fact have an effect on the tone of the guitar.
What really matters more is the density of the material. Quality components will have more weight to them. This can increase the sustain you get from the instrument. This effect is more noticed on bridges. Some people have said the tone is warmer with heavier pieces of hardware, but not enough evidence is present to either confirm or deny that right now.
As of late, I’ve seen a few articles and speculation on forums that wood is not a factor in tone at all. Consider this, different woods resonate differently due to differences in density. These differences allow us to hear different tones out of a giving wood. How can wood sound the same if in fact each species is different and not the same density? That is my argument to that idea. To say there is no difference is ignorant. The change in tone will be noticeable from wood to wood, but you must also consider all the other factors that go into the guitar. Thickness of the finish, hardware quality, pickups, cables, tubes, amp circuitry, and the speaker in that amp are all adding bits to the tone.
I can see why people would say there is no difference given all the added colors, but if you listen to a guitar, you can pick out those differences. Every piece of wood, even from the same tree can have a different tone. When considering a guitar, be it production or custom shop, consider all the variables that will be in your tone. If you take the time to research your gear, you can better choose a guitar to go for a specific tone and know what tonal qualities a guitar will have given the wood used. In turn, you’ll end up with an instrument that you will really be happy with. If you’re spending your hard earned dollars on it, you really should get exactly what you want.