complex tone

In acoustics, tone refers to sound recognized by its regular vibration. A simple tone has a single frequency, while a complex tone is composed of multiple simple tones, including a fundamental frequency and overtones. When overtones are whole multiples of the fundamental, they are called harmonics, and a combination of harmonic tones is perceived as musical.

Sound itself is a mechanical disturbance that travels as a longitudinal wave through an elastic medium. This wave consists of alternating compressions and rarefactions, or regions of high and low pressure. Sound cannot travel through a vacuum because there is no medium to carry these disturbances. The speed of sound varies depending on the medium; it travels faster in liquids and solids than in gases due to the closer proximity of particles. Properties like frequency determine pitch, while amplitude determines loudness.