The resonant properties of the soundboard and the interior of the instrument greatly increase the loudness of the vibrating strings.
[1] "The sound board is probably the most important element of a guitar in terms of its influence on the quality of the instrument's tone [timbre].
Through this process, an alternating series of compression and rarefaction pulses travel away from the soundboard, creating sound waves.
Skin or plastic are found on instruments in the banjo family, and harpsichord makers have experimented with metal soundboards.
Wooden soundboards, with the exclusion of those found on keyboard instruments, typically have one or more sound holes of various shapes.
The acoustic properties of an instrument are also influenced by the wood's cutting profile, the direction of its fibres and the lack of knots.