Acoustic Guitar Sound Vocabulary

As you start to sort through the endless possibilities of how you want your guitar to sound, take a few minutes to brush-up on how some of the tonewood tonal characteristics can be described. Again, this can be as much of a science as you want it to. If that is not in your DNA, no problem, just build the most beautiful instrument that appeals to YOU!

Fundamental vs. Overtones  

A fundamental tone is the initial sound heard when you pick or pluck a note (and which  decays at varying rates depending on the sustain).

The overtones are complex harmonic layers that can make the note swell after the fundamental sound is initiated.

Harmonic Content

A piece of wood is capable of producing a fundamental tone and an array of harmonics (which include overtones). Tapping a piece of wood reveals, not only the velocity of sound, but also harmonic content, clarity of tone, and high-, low-, and mid-biases.

Headroom

How loudly an instrument can be played without the loss of definition or quality of sound.

Projection

The tonewood's ability to amplify or magnify sound so that it's voice can be heard over a larger area without amplification

Sustain

Natural reverberation that results in a lasting, ringing tone.

Torrefaction

A process in which the soundboard is thermally cured in an oxygen-free environment to alter the cellular structure of the wood in a manner that replicates an aged wood. The result should be a guitar soundboard that is manually "aged" prior to building the instrument.

Because of the extra care and handling, these tops can often be higher in price. As always, many debate the process' ability to age the wood when compared to a naturally aged sound board.

Velocity of Sound

The speed at which a material transmits received energy. Lively materials—those with a high velocity of sound, or low internal damping—best facilitate the transmission of vibrational energy (sound waves oscillating from the bridge). To test velocity of sound, a luthier will hold a piece of wood at a nodal point and tap it to listen for the response.