There are 6 main varieties of tubas, each with its own unique sound and purpose:
1. Orchestral tuba: The most common type of tuba used in orchestras. It has a large bell and a relatively low pitch.
2. Bass tuba: Similar to the orchestral tuba but with a larger bell and an even lower pitch.
3. Sousaphone: A marching tuba with a large bell that projects its sound forward.
4. Contrabass tuba: The lowest-pitched tuba, with a bell up to 48 inches in diameter.
5. Euphonium tuba: A smaller tuba that is pitched between the tuba and the trombone.
6. Cimbasso: A rare type of tuba that was invented in the 1830s. It is similar to the euphonium but with a larger bell and a lower pitch.