mute

In music, any device used to dampen the vibration of an instrument and so affect the tone. Orchestral strings apply a form of clamp to the bridge - the change is used to dramatic effect by Bartók in the opening bars of Music for Strings, Percussion, and Celesta (1936). Brass instruments use the hand or a plug of metal or cardboard inserted in the bell.

Although the word implies a reduction of volume, a variety of mutes used in big band jazz are used principally to vary the quality of tone, as in Stravinsky's Ebony Concerto (1945).