Brass instrument can be very useful for a 1st or 3rd horn player, who uses the F side less. Another approach was the addition of two sets of slides for different parts of the range. Some euphoniums and tubas were built like this, but today, this approach has become highly exotic for all instruments except horns, where it is the norm, usually in a double, sometimes even triple configuration. Some valved brass instruments provide triggers or throws that manually lengthen (or, less commonly, shorten) the main tuning slide, a valve slide, or the main tubing. These mechanisms alter the pitch of notes
Tuba including Ralph Vaughan Williams (Tuba Concerto), Edward Gregson, John Williams, Alexander Arutiunian, Eric Ewazen, James Barnes, Joseph Hallman, Martin Ellerby, Philip Sparke, Kalevi Aho, Josef Tal, Bruce Broughton (Tuba Concerto) and David Carlson. Tubas are found in various pitches, most commonly in F, E, C, or B. The main tube of a B tuba is approximately long, while that of a C tuba is , of an E tuba , and of an F tuba . The instrument has a conical bore, meaning the bore diameter increases as a function of the tubing length from the mouthpiece to the bell.