An alto trombone is a brass instrument that is higher in pitch than the more common tenor trombone. Trombones are unlike most brass instruments because the player changes the note by moving a slide rather than by pressing different combinations of valves. The instrument is usually pitched in the key of E flat, but is also often found in the key of F and D. The appearance of the alto trombone is like a tenor trombone, only smaller. An alto trombone has a range from A2 to G5, meaning the A found in the second octave on an 88-key piano to the G found in the fifth octave.
All different types of trombones are members of the brass family of instruments. Players produce sound on brass instruments by “buzzing” their lips into the mouthpiece while pushing air through it. On most instruments in the brass family, the note produced is changed by different valves which alter the effective length of the instrument. Most brass instruments are pitched in the key of B flat.
The appearance of an alto trombone is very similar to the appearance of a tenor trombone. The sound is projected by a large flared bell which occupies the highest position on the instrument. The slide extends out in front of the player and is rectangular in shape, with a rounded outer edge. Players blow into the mouthpiece, a small cup-shaped attachment found on the opposite end of the instrument to the rounded end of the slide. The majority of the construction of the alto trombone is made up of metallic tubes, supported by braces.
Notable differences between the alto trombone and most brass instruments are the way in which the note is changed and the key the instrument is in. Unlike most brass instruments, a sliding mechanism is used to change the note on trombones. This enables more precise changes in the pitch of the note produced and allows trombonists to play more notes. The key of the alto trombone is usually E flat, but it can also be D or F, in some instances.
Higher pitches can be reached on the alto trombone than with most other trombones. The ordinary tenor trombone has a range from E2 to F5. An alto trombone can produce notes from A2 to G5 easily, and experienced players may be able to produce even higher notes.