Choosing a Tuba
Choosing Your First Tuba

Although they are all called tubas, the instrument comes in different sizes. In general, a tuba is quite big and is played while resting its weight on a chair or the musician's knee. Your first task should be to actually hold the tuba and make sure that the mouthpiece is at the right height and that you can reach the valves easily. You should start by trying out a variety of different tubas.
(Source: Dictionary of Fun Facts on Brass Instruments [in Japanese], published by Yamaha Music Media)

From low to high tonal range, tubas can be pitched in B♭, C, E♭, or F. Among these, the B♭ tuba is widely used in brass bands and orchestras.
(Source: Dictionary of Fun Facts on Brass Instruments [in Japanese], published by Yamaha Music Media)