Bass Tuba, brief description
“The tuba is currently used in four tunings: the bass tuba in F and Eb, and the contrabass tuba in C and Bb. In Austrian and French orchestras tubas in F and Bb are used, the contrabass tuba in Bb being found primarily in opera orchestras. In some regions of Germany and in Scandinavia, the United Kingdom and the USA the C tuba with four valves is common as a kind of all-round instrument: it is played not only in the orchestra but also in chamber music and as a solo instrument.”
Tuba: Instrument Guide — Yamaha
“The tuba, which produces the lowest pitched sound of all brass instruments, brings an essential luster and sheen to any musical genre from jazz and classical through to pops.”
Tuba: Instrument Studies for Eyes and Ears — Jacobs School of Music
Instrument Studies for Eyes and Ears, by Don Freund, site designed by Reid Merzbacher
Tuba: The Orchestra: A User's Manual — Andrew Hugill
“The aim of The Orchestra: A User's Manual is to provide information about the orchestra, orchestration, composition and instruments, for the benefit of anybody with an interest in the subject.”
Tuba: The Orchestra Up Close — Orchestre Métropolitain
“The player rests the instrument on their leg, who produces sound by blowing and “buzzing” into the mouthpiece, pushing down or releasing the valves to change the pitch.”