A mute is a special device that dampens an instrument's sound and at the same time changes its timbre, giving it a special colouring. A composer indicates this with the instruction con sordino (“with the mute”), and its removal with senza sordino.
On the bowed strings the mute (a comb on the bridge) makes the sound muffled, tender, matte, “veiled” — ideal for mysterious, lyrical episodes. On the brass (trumpet, trombone) there is a whole family of mutes (straight, “wah-wah,” cup) that give a sharp, nasal, “stifled” timbre — indispensable in jazz. The mute fundamentally transforms the character of the same instrument's sound, and so is an important coloristic means in both academic and popular music.
