harmon mute
A hollow metal mute inserted into a brass instrument's bell, famous for producing the thin, buzzy "wah-wah" sound associated with jazz trumpet.
In Depth
The Harmon mute (also called a wah-wah mute or bubble mute) consists of a metal tube surrounded by a cork-lined outer shell that seals the bell of a trumpet or trombone. A removable central stem can be adjusted or removed entirely, each position producing a different tonal quality — from a tight, buzzy sound with the stem in to a more open, nasal quality with it removed. Miles Davis transformed the Harmon mute into one of the most recognizable sounds in music. His use of it close to the microphone, with the stem removed, created an intimate, breathy whisper that defined albums like Kind of Blue and Sketches of Spain. The technique became so associated with Davis that the sound itself evokes his artistic persona. Film and television composers frequently use Harmon-muted trumpet to signify noir atmosphere or urban sophistication.
Miles Davis so thoroughly owned the Harmon mute sound that when people hear it today, they reflexively think of him — no other instrumentalist has so completely claimed a piece of equipment.