There are many styles of trombones, and their classification depends partly on the size of the bore. Small-bore trombones typically have a bore size of exactly 1/2-inch -- in some cases, slightly smaller. Understanding the difference between bore sizes in trombones will help you to select the proper trombone for your needs.
The tenor trombone has a bore size of 1/2-inch. The tenor is the most common trombone in the trombone family; it has the same approximate range as a trumpet, although it sounds an octave lower. The tenor trombone falls into the largest category of small-bore trombones -- that is, it has the largest possible bore without exceeding the criteria required to be classified as a small-bore instrument. As a result of its small bore, the tenor trombone produces a clear, penetrating sound.
The alto trombone also uses a bore size of approximately 1/2-inch. Alto trombones have a higher register than a tenor trombone; although they usually have the same-sized bore as the tenor, the difference in pitch comes from the overall construction of the instrument. The alto trombone boasts a smaller slide a and more compact mouthpiece, making it ideal for alto parts in a trombone choir.
The soprano trombone has a bore size of approximately 0.45 to 0.47 inches, similar to the bore of a trumpet. Soprano trombones have the smallest bore of any trombone, and its smaller bore makes the instrument more compact and creates more resistance against the player's airflow; this resistance makes it a difficult instrument to play well. The soprano trombone usually appears in trombone choirs playing the soprano part.
The valve trombone doesn't use a slide, instead, it employes valves similar those found on a trumpet or baritone. Valve trombones have the same range as a tenor trombone but lack the slide mechanism which allows for effective glissandos. The bore size of the valve trombone qualifies as a small bore and usually extends no larger than 1/2-inch. The valves make it easier to accurately play fast passages, but its restricted airflow changes the sound of the instrument slightly.
- PhotoObjects.net/PhotoObjects.net/Getty Images