a resonant body. The harmonics, which are superimposed on the fundamental frequency and are always a multiple of it, determine the sound pattern. The sound thus presupposes that the individual oscillations are in an integer relationship to each other. It is only by combining all the frequencies that the characteristic sound of the instrument is produced. The lowest frequency of a sound is its fundamental. A sound can therefore be a single tone with overtones, but also a chord. Sounds can be recognized by a discrete frequency spectrum in the Fourier transform
. Each fundamental and harmonic has its own spectral line. Sound can be produced by sound bodies and instruments, but also synthetically by sound synthesis.