A mute is a device placed in or over the bell of a brass instrument to soften or change its tone. Jazz trumpeters use several kinds, including the straight mute, the cup mute and the plunger, but the most famous is the Harmon mute: a bulbous metal mute with a cork ring that seals the bell, forcing all the air through it, and an adjustable central stem. With the stem in, covering and uncovering its end with the hand produces a talking “wah-wah” effect, which gave guitar wah pedals their name.
Miles Davis played the Harmon mute with the stem removed on many of his best-known recordings, creating a close, breathy, slightly metallic sound that seems to speak directly into the listener’s ear. That intimate quality makes muted trumpet one of the most popular melodic colours in jazz lo-fi, whether sampled from records or played by contemporary musicians.