Harmonics, hahr MON ihks, are the components of a musical tone. A tone is actually a blend of several separate tones. This blend, called a composite tone, is caused by a set of vibrations, such as those made by a musical instrument or the human voice. For example, a violin string vibrates over its entire length. But it also vibrates in segments, called partials, which are shorter than the total length of the string. The string vibrates in segments such as one-half, one-third, or one-fourth, of the string. Each vibrating segment produces a separate tone, called an overtone.