Acoustic Guitar Wood Types
By: Phil Dyck
There are many factors to consider when beginning any woodworking project; how much material do I have to work with, what’s my budget, what’s my timeframe, etc. These issues become move critical when you are building a musical instrument. Not all woods share the acoustical qualities necessary and it is important to know what to look for, otherwise you’ll end up with a guitar what sounds like a tin can.
Tonewoods
Tonewoods are types of wood with consistent and recognized acoustical properties. They can be hardwoods or softwoods and are found in all areas of the world. Thetonewood will vary with the part of the instrument it is going to be used for, typically dense materials for the sides, back and fretboard and light, stiff materials for the top, or soundboard. Quite simply, dense material transmits sound slowly and stiff, light material transmits sound faster.
There are 3 sections of the guitar which we will concern ourselves with for sound production and transmission:
Soundboard– the top of the guitar where 90% of the sound is created, wood selection is the most important here.
Sides/Back– usually have different characteristics than the soundboard to create a balanced sound. The sides and back are made of the same material for purely aesthetic reasons.
Fretboard/Fingerboard– made from dense wood which transmit sound slowly, thus not affecting the sound from the guitar.
Below are lists of tonewoods available for each of the 3 above sections.
Quarter-Sawn vs. Flat-Sawn
The final consideration when it comes to the construction of musical instruments is their durability. After spending a lot of time and energy bending the sides, shaping the neck and cutting the frets the last thing you want is the guitar to break when its finally strung. It is also important that the guitar doesn’t warp and crack the soundboard or render the neck unplayable. Most musical instruments, and fine furniture, are built from quarter-sawn lumber as opposed to flat-sawn lumber.
Flat-sawn lumber is cut with its wide face parallel to the annual growth rings of the log. Flat sawing lumber is quick and produces less waste, but creates a less stable piece of lumber. Flat sawn boards have a lot of flex in them and can bend under pressure. An example of a flat-sawn log can be seen below.
Quarter-sawn lumber, on the other hand, is cut with the narrow side of the board parallel to the annual growth rings. Quarter-sawn lumber will produce more waste than flat-sawing, but produces a much more attractive and stable board. They act the opposite of flat-sawn boards, having little flex and do not bend as much under pressure. Due to their stability, quarter-sawn materials are preferred by luthiers (makers of stringed instruments). An example of quarter-sawn log can be seen below.