The Importance of Wood

Many different woods are used for building guitars, but how do these woods affect the sound of the instrument? Traditionally guitars and basses have been made of mahogany, rosewood, maple, ebony, ash and alder. Here we will look at the strengths and weaknesses of the woods most commonly used today for bodies, necks and fretboards of 12-string basses.

There are many complex differences between woods, even within a species. Many factors ensure that no two pieces of wood are exactly alike. The environment, the tree's age, genetics, grain orientation and curing conditions all have an effect on the tonal properties of a piece of wood. Tonewoods also respond differently when fashioned into different shapes. A solid piece of mahogany is going to sound different from a chambered piece even if it is the same dimensionally.

Quilted maple billets

The speed at which a material transmits received energy is referred to as Velocity of Sound. A picked string transmits energy to the bridge and the bridge in return oscillates one surface of a body of wood. When building a guitar or bass body the luthier must make it out of materials that facilitate the transmission of this energy. Woods with a high velocity of sound make the best transmitters.

Judging the sound velocity of a piece of wood is a relatively simple process. Generally a luthier will hold the wood billet at one corner, tap it, and then listen to the response from the wood. A lively piece of wood will ring instantly and hold its tone much in the same way a bell does. The most lively woods ring well no matter where you hold or tap them.

Another thing that luthiers listen for is the harmonics that the wood produces. When tapping a billet you will first hear an initial tone, but as that tone fades you will hear a series of harmonics develop. Although these elements will be altered some by cutting and shaping the wood into the form of a body, these basic characteristics will be inherent to the finished instrument.

 

Book-matched curly maple blanks

Each piece of wood in an instrument adds something to the overall character of that instrument. Maples tend to be bright and bring out the frequencies that define clarity, while mahoganies are more subdued tonally and add warmth to the instrument's tone. Maples are also more acoustically transparent whereas mahogany adds a "woody" characteristic to the instrument's overall tone. Gibson saw early on that these two woods complemented each other and added a maple cap to the mahogany body of their Les Paul models. The rest, as they say, is history.

 

Honduran mahogany neck blank

Rosewoods have a very high velocity of sound and a broad range of harmonic overtones. They are rich in lower harmonics but are also strong in mids and highs. This full-range characteristic makes rosewoods such as Brazilian and Indian an excellent choice for fretboards as rosewood is also very durable. Most 12's have rosewood fretboards.
 

 

East Indian Rosewood billets

Ebony is typically found as a fretboard wood on high-end guitars and basses. Jol Dantzig of Hamer Guitars USA said of ebony, "I find it quite hard and a ready conductor of vibration, particularly at the higher frequencies." The fretboard wood does affect the sound of the instrument, but not dramatically. Adding a fretboard with specific tonal qualities can enhance or "edit" the overall tone of the instrument. Again Dantzig states, "Tone is quite subjective and sometimes different combinations of woods are used to change the balance of the 'Velocity'." Fretboard materials are never the defining tonal elements of an instrument.

 

Ebony fretboard blanks

All 12-string basses can be and are made from many different combinations of woods. The most common combination is a mahogany body paired with a maple neck and rosewood fretboard. This is a very traditional and effective combination of woods for a 12, but by no means does it rule out other combinations being equally good. With the 12-string bass having such a broad frequency range it is important for a luthier to keep this in mind when building one and to choose woods that will facilitate the transmission of these frequencies properly to achieve the desired overall tone.

It is important to remember that quality of wood, the luthier's skill, design of the instrument and electronics all play an important part in the instrument's overall tonal quality. It is equally important to keep in mind that "good" versus "poor" tone is in the ear of the listener and is completely subjective. While there are some commonly accepted qualities that are generally deemed as desired tonal characteristics, there are no black and white answers when it comes to what constitutes good tone.

 

"uuh, huh-huuh... you said 'wood'..."