Tuba after American bandmaster John Philip Sousa, resembles a hélicon with the bell pointed up (in the original models as the J. W. Pepper prototype and Sousa's concert instruments) and then curved to point forward (as developed by Conn and others). Some ancestors of the tuba, such as the military "bombardon", had unusual valve and bore arrangements compared to modern tubas. During the American Civil War, most brass bands used a branch of the brass family known as "saxhorns", which, by today's standards, have a narrower bore taper than tuba—the same as true cornets and baritones, but distinct from trumpets, euphoniums,
Tuba is written in bass clef in concert pitch, so tuba players must know the correct fingerings for their specific instruments. Traditional British-style brass band parts for the tuba are usually written in treble clef, with the B tuba sounding two octaves and one step below and the E tuba sounding one octave and a major sixth below the written pitch. This allows musicians to change instruments without learning new fingerings for the same written music. Consequently, when its music is written in treble clef, the tuba is a transposing instrument, but not when the music is in bass clef. The