Euphonium are the tuba-euphonium quartet or larger tuba-euphonium ensemble; the brass quintet, where it can supply the tenor voice, though the trombone is much more common in this role; and other mixed brass ensemble. Such ensembles are almost non-existent: they are more likely to be semi-professional or amateur in nature. Most of the United States Armed Forces service bands include a tuba-euphonium quartet made up of players from the band that occasionally performs in its own right. The euphonium is not traditionally an orchestral instrument and has not been common in symphony orchestras. However, there are a few works from the
Tuba including Ralph Vaughan Williams (Tuba Concerto), Edward Gregson, John Williams, Alexander Arutiunian, Eric Ewazen, James Barnes, Joseph Hallman, Martin Ellerby, Philip Sparke, Kalevi Aho, Josef Tal, Bruce Broughton (Tuba Concerto) and David Carlson. Tubas are found in various pitches, most commonly in F, E, C, or B. The main tube of a B tuba is approximately long, while that of a C tuba is , of an E tuba , and of an F tuba . The instrument has a conical bore, meaning the bore diameter increases as a function of the tubing length from the mouthpiece to the bell.