What is alto trombone?

The alto trombone is a type of trombone that is pitched in E♭, a fourth higher than a tenor trombone. It is smaller in size and has a higher range than a tenor trombone, making it ideal for playing in higher registers. The alto trombone is commonly used in orchestras, brass bands, and jazz ensembles for its unique sound and ability to add variety to the trombone section. In terms of construction, the alto trombone is similar to a tenor trombone but with a smaller bore size and a shorter slide. It is less commonly used than the tenor trombone but is still an important instrument in the trombone family.