Overview
The source of sound in an acoustic guitar is the string, which is plucked with the fingers or with a plectrum. The string vibrates at a fundamental frequency but also creates many harmonics at different frequencies. The frequencies produced depend on string length, mass, and tension. The string causes the soundboard and sound box to vibrate, and as these have their own resonances at certain frequencies, they amplify some string harmonics more strongly than others, hence affecting the timbre produced by the instrument.