Editing Tuba (section)

===Size vs. pitch===
In addition to the length of the instrument, which dictates the fundamental pitch, tubas also vary in the overall width of the tubing sections. Tuba sizes are usually denoted by a quarter system, with {{frac|4|4}} designating a normal, full-size tuba. Larger rotary instruments are known as ''kaiser tubas'' and are often denoted {{frac|5|4}}. Larger piston tubas, particularly those with front action, are sometimes known as ''grand orchestral tubas'' (examples: the Conn 36J Orchestra Grand Bass from the 1930s, and the current model Hirsbrunner HB-50 ''Grand Orchestral'', which is a replica of the large York tubas owned by the Chicago Symphony Orchestra). Grand orchestral tubas are generally described as {{frac|6|4}} tubas. Smaller instruments may be described as {{frac|3|4}} instruments. 
[[File:230128-N-DK722-1001 - NAVEUR-NAVAF Band play live on Channels News.jpg|thumb|Nolan Derrick plays the tuba/sousaphone, showing a different series/model of tuba/sousaphone]]
No standards exist for these designations, and their use is up to manufacturers, who usually use them to distinguish among the instruments in their own product line. The size designation is related to the larger outer branches and not to the bore of the tubing at the valves, though the bore is usually reported in instrument specifications. The quarter system is also not directly related to bell size, though there is typically a correlation. {{frac|3|4}} tubas are common in American grade schools for use by young tuba players for whom a full-size instrument might be too cumbersome. Though smaller and lighter, they are tuned and keyed identically to full-size tubas of the same pitch, although they usually have 3 rather than 4 or 5 valves.