<P> The instrument proved practical for marching, and by 1908 the United States Marine Band adopted it . </P> <P> Versions with the characteristic extra 90 ° bend making a forward - facing bell were developed in the early 1900s . Early sousaphones had 22 - inch - diameter (560 mm) bells, with 24 - inch (610 mm) bells popular in the 1920s . From the mid-1930s onward, sousaphone bells have been standardized at a diameter of 26 inches (660 mm). Some larger sousaphones (Monster, Grand, Jumbo, Giant or Grand Jumbo, depending on brand) were produced in limited quantities . </P> <P> The sousaphone is a valved brass instrument with the same tube length and musical range as other tubas . The sousaphone's shape is such that the bell is above the tubist's head and projecting forward . The valves are situated directly in front of the musician slightly above the waist and all of the weight rests on the left shoulder . The bell is normally detachable from the instrument body to facilitate transportation and storage . Except for the instrument's general shape and appearance, the sousaphone is technically similar to a tuba . </P> <P> For simplicity and light weight, modern sousaphones almost always use three non-compensating piston valves in their construction, in direct contrast to their concert counterparts' large variation in number, type, and orientation . Both the tuba and sousaphone are semi-conical brass instruments . No valved brass instrument can be entirely conical, since the middle section containing the valves must be cylindrical . While the degree of bore conicity does affect the timbre of the instrument, much as in a cornet and trumpet, or a euphonium and a trombone, the bore profile of a sousaphone is similar to that of most tubas . </P>

What is the difference between tuba and sousaphone