Alto trombone

The alto trombone (German: Altposaune, Italian, French: trombone alto) is the alto member of the trombone family of brass instruments, smaller than the tenor trombone. It is almost always pitched in E♭ a fourth higher than the tenor, although examples pitched in F are occasionally found. The alto trombone was commonly used from the 16th to the 18th centuries in church music to strengthen the alto voice, particularly in the Mass. Alto trombone parts are usually notated in alto clef.