TubaTubas are brass instruments with the lowest tonal range, but they have slight variations. In addition to different possible structures, the four main pitches are F, E♭, C, and B♭. The baritone, euphonium, and sousaphone are also companions of the tuba.

Tuba, deep-pitched brass wind instrument with valves and wide conical bore. The word tuba originally was the name of a straight-built Roman trumpet and was the medieval Latin word for trumpet. Valved bass brass instruments for bands are mentioned as early as 1829, but little is now known about them. In 1835 Wilhelm Wieprecht and Johann Gottfried Moritz of Berlin patented the bass tuba in F, with five valves. Subsequent designs were considerably influenced by the French contrabass saxhorn.

Modern military and brass band tubas are of two sizes used together: the E♭ bass (or bombardon) and the BB♭ bass, a fourth lower. When these tubas have three valves, their lowest notes are, respectively, the A below the bass staff and the E below that. The E♭ bass generally has a fourth valve that lowers the basic pitch by a fourth to BB♭, enabling the instrument (with use of valves) to produce the low E, below which the compass can be continued downward in fundamentals (lowest note producible by a length of tubing), E♭, D, and so on. These basses are coiled vertically and held upright aslant the player’s body, with the bell pointing to the right; in the United States the bell may be turned forward. Alternative designs, likewise in E♭ and BB♭ but encircling the body, include the circular bass, or helicon, with the bell resting across one shoulder, and the American sousaphone, with an extremely wide bell raised above the player’s head.