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
British brass band horns, which are found in orchestras and concert bands. The standard instrumentation is as follows: The above totals 27–29 players, although in practice a band often has fewer than this. Spare seats may be filled for concerts and contests by players brought in from other bands, commonly known as "deputising players" or "deps". With the exception of percussion, bass trombone and some tenor trombone music, all parts are transposing and written in the treble clef with the instrument's lowest open note (B♭ or E♭) notated as middle C. This means that for every valved instrument, from the basses to the