At Eastman Strings, we put a lot of emphasis on the quality of the craftsmanship of our instruments. Of equal importance in the outcome of a violin maker’s efforts is the quality of the materials used to make the instruments. For nearly every part of a bowed stringed instrument, “material” means “wood.”

The term tonewood is used when talking about the woods that make up the body of the instrument, as opposed to the fittings. The category of tonewood is subdivided into two sub-categories: soft wood for the tops, and hard wood for the backs, ribs (sides), necks, and scrolls.

If you’ve ever bumped your knee on a table leg, or hit your head on a door jamb, you probably think that all wood is hard! Still, there are variations in hardness among different types of wood. Instrument tops are made of what we call soft wood, and in virtually all cases, this means spruce. Pine and some other evergreens, such as cedar, are also softwood trees, and their wood is occasionally used in instrument making as well. But the vast majority of instrument tops are made of spruce. This wood is used because it tends to have straight, even grain structure, and when it is carved to the right shape and thickness, it is very resonant, a quality needed for good sounding instruments.

Examples of tonewood clockwise from top left: plain maple, flamed maple, plain poplar (cut on the slab) and flamed Lombardy poplar. Note that the colors of these samples derive from the instruments' varnish, not the color of the wood itself.

The hard tonewood for the backs, ribs, necks, and scrolls is usually maple. Again, there are alternatives, such as poplar, birch, pear wood, and so on, but maple is the standard. The Golden Age Italian masters made fairly frequent use of poplar for cello and viola backs, and at Eastman Strings, we use both Canadian poplar and highly flamed Italian Lombardy poplar for some models. The rest of our models are made of maple. These hard woods are used because of their structural strength, and in the case of the backs, because they can reflect sound, giving the instruments good tonal projection.

One characteristic of maple is that some trees have wood with beautiful figures in it. Because these figures seem to shimmer and move when the light angle changes or the wood moves, they are often called “flame.” Not all maple wood has flame, and flame can be found in different amounts in different pieces of wood. People have long valued the beautiful appearance of flamed maple, and because of its rarity and higher cost when compared to plain maple, flamed maple is usually used for the building of more expensive instruments. Flamed maple does not necessarily sound any better than plain maple, but over the centuries, the tradition of reserving the prettier wood for the more carefully crafted instruments has resulted in a general belief that instruments with flamed maple backs and ribs are better instruments. German makers of the last century created model designations among which the amount of flame in the maple was a distinguishing factor. This tradition is the basis for the way many workshops today, including Eastman Strings’ Beijing and European workshops, allocate their wood and differentiate their models.

The way wood is cut and seasoned has a lot to do with whether it will make good tonewood. There are two basic ways to cut a log into pieces of wood for making instruments. The wood resulting from these two methods is called “quarters” and “slabs.” Most tonewood is cut into quarters. (This does not mean, as the word might imply, the logs are cut into four equal pieces, or literal “quarters”. Instead, the word derives from a more obscure definition of “quarter” meaning that each wedge of wood is cut from the log lengthwise with its inner edge oriented toward the center of the log.) You can think of quartered wood as being like slices of a pie. (See Illustration 1.) This is the most efficient way to get a lot of good quality tonewood with properly aligned grain from a log without a lot of waste. Spruce used for making tops is virtually always quarter-cut, and maple usually is too. Alternatively, maple and other hard woods are sometimes cut into slabs. (See Illustration 2.) There is a fair amount of waste associated with this method of cutting wood, but the resulting slabs often have spectacular flame, and it is often possible to make beautiful one-piece backs from the larger slabs.

Whether cut into quarters or slabs, tonewoods must be carefully seasoned before they are used. This means that they must be properly cut, stacked, and stored for a long period. Often the ends of the pieces of wood are covered in wax to make sure that the moisture in the wood doesn’t simply ooze out of the end of the cut grain, but rather evaporates slowly through the wood’s sides. Wood that dries too rapidly often checks, which means that cracks along the grain appear spontaneously as the wood shrinks from the loss of moisture. Most makers won’t use wood if it hasn’t seasoned for more than five years, and most prefer wood to be as old as possible before use. (Slow drying helps ensure that wood does not develop any internal stresses, but kilns that speed up or guaranty the thoroughness of drying are sometimes employed.) Some private tonewood stocks contain wood that is up to 100 years old or more! Good tonewood this old can be very valuable.

Quarters of spruce and maple that are ready to use for making instruments are sawn in half lengthwise, and the wide edges are planed flat and glued to each other. (See Illustration 3.) This is called “bookmatching,” and it’s fairly easy to see why. It’s as if the piece of wood were opened up like a book, and the wider part of the wood, representing the book’s spine, becomes the joint between the two pieces of wood. This results in a piece of wood that is tall in the middle and short at the edges, perfect for accommodating the arched shape of stringed instrument tops and backs. The center seam is usually visible on finished instruments, particularly on backs made of flamed wood.

Spruce is also used to make corner blocks, end blocks, and rib linings (see our workshop tour) These are not readily visible on finished instruments because they are on the inside. If there is enough light, you can peer through the f-holes and see some of these parts where the ribs meet the back, and where the corners come together. As an alternative to spruce, blocks and linings can be made from willow or poplar. These blocks need to be light and strong. Also located inside the instrument but visible through the f-holes is the soundpost. This is a dowel of fine-grained spruce that performs important structural and tonal roles. Note that the soundpost is not glued in place, and sometimes comes loose, requiring re-fitting by a qualified luthier.

There is one last piece of tonewood needed to make an instrument function, and like the soundpost, it's not permanently attached: the bridge. Bridges are made of quartersawn maple with especially close, even grain. Bridge blanks, the basic piece of wood from which bridges are hand cut for each instrument, range in quality depending on the grain structure and age of the wood, and can be quite expensive. The dark flecks between the grain lines on bridges, known as “spiegel,” are considered a sign of quality, and bridges with lots of evenly spaced flecks are prized.

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Bookmatching quarter-sawn tonewoods:
1. A seasoned quarter of wood is split lengthwise into two.
2. These two halves are then "opened up" like a book, with the wide edges together.
3. Next, the surfaces of the wide edges are planed flat to create matching surfaces.
4. The planed surfaces are then glued together to make a two-piece top or back. 5. The resulting piece of wood has the necessary height at the center to allow for the instrument's arching.