I’m not proud, but I’ve always thought of tubas as obese trumpets you wear. Not for lack of respect, (I played a wind instrument! I actually like polka! Some of my best friends were in marching band!) but they’re silly looking. I was fine treating them like a baritone bowl.
Forgive me, but I’m going to assume you know as much about the tuba as I did, which was nearly nothing past its “definitely an instrument” status. The tuba is a wind instrument in the brass family. It is powered by pushing vibrating air straight from the mouth through its amplifying metal wiggles. Tone is affected by the vibrations of the players’ own lips, and articulated by valves that divert air through secondary tubes. These smaller tubes augment the effective length of the tuba, and are meticulously designed to shift the tone’s pitch in specific increments.
Like most instruments, tubas vary in size and shape for different styles of play, and to convey different fundamental pitches. The longer the tuba the lower the sound. Put clumsily, the total length of a tuba’s central tube determines its pitch, a bit like the amount of remaining beer sets the tone when you blow into the bottle.
Sorgente: How Does A Tuba Do Its Oomping? – Core77