Alto Trombones

The alto trombone is much rarer today than the tenor and bass trombones. It is mostly in E-flat, rarely in F, and is usually not-transposed in the alto clef. The construction of the alto trombone differs from the tenor trombone in that it has a shorter tube length and a smaller bell with a diameter of between 165 and 177 millimeters (6.5 to 7 inches). The alto trombone sounds more brilliant than the larger instruments.