Arutiunian, Eric Ewazen, James Barnes, Joseph Hallman, Martin Ellerby, Philip Sparke, Kalevi Aho, Josef Tal, Bruce Broughton (Tuba Concerto), John Golland, Roger Steptoe, David Carlson, Jennifer Higdon (Tuba Concerto), and Marcus Paus (Tuba Mirum). Types and construction Tubas are found in various pitches, most commonly in F, E, C, or B. The key of a tuba depends on the fundamental pitch of the instrument, or fundamental note in the series of overtones (also called partials) available without any valves being pressed. Tubas in different keys use different lengths of tubing. 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. The conical bore causes the instrument to produce a preponderance of even-order harmonics. A tuba with its tubing wrapped for placing the instrument on the player's lap is usually called a concert tuba or simply a tuba. Tubas with the bell pointing forward (pavillon tournant) instead of upward are often called recording tubas because of their popularity in the early days of recorded music, as their sound could more easily be directed at the recording microphone. When wrapped to surround the body for cavalry bands on horseback or marching, it is traditionally known as a helicon. The modern sousaphone, named after American bandmaster John Philip Sousa, resembles a helicon with the bell pointed up (in the original models as the J. W. Pepper prototype and Sousa's concert instruments) and then curved to point forward (as developed by Conn and others). Some ancestors of the tuba, such as the military bombardon, had unusual valve and bore arrangements compared to modern tubas. During the American Civil War, most brass bands used a branch of the brass family known as saxhorns, which, by today's standards, have a narrower bore taper than tuba—the same as true cornets and baritones but distinct from trumpets, euphoniums, and others with different tapers or no taper. Around the start of the Civil War, saxhorns manufactured for military use in the USA were commonly wrapped with the bell pointing backwards over the player's shoulder, and these were known as over-the-shoulder saxhorns, and came in sizes from cornets down to E basses. However, the E bass, even