Original Source:http://www.tubanews...

There has probably been more written about mouthpieces than any other aspect of tuba, or any brass instrument for that matter. I was never very much a mouthpiece person. I have friends and colleagues who have tried almost every mouthpiece that exists and can tell you everything about each one of them; they know the cup size, the rim size, the rim thickness, the choke size, every idiosyncrasy of the back bore and the exact weight. Further, they can give you a detailed verbal description how each of these aspects affect the way an instrument plays.   

That’s a pretty dense paragraph and at first read it may appear to be sarcastic, it absolutely isn’t meant to be. I deeply admire those mouthpiece sages, I’m even a little jealous of them. I would like to know the secret formulae to

Original Source:http://www.galvanizedjazz.com/tuba/altfingerings.html

Alternate fingerings can be used to compensate for intonation problems that are unique to a particular instrument. They are also useful when you have a rapid slurred passage in which two or more consecutive notes have the same fingering. (Just use a different fingering for one of the notes.)

The note that you want to play is a certain number of semitones down from any “open” note above it. For example, on a BBb tuba we might play the Db in the middle of the bass clef staff with the second valve, because it is one semitone below open D. But there is an open F above that D, which may have better intonation. By counting semitones down the chromatic scale from F to Db we see that we need a fingering that will bring the horn down 4 semitones. Looking at a fingering chart, we find that the Db can be fingered 23. You probably knew that already, since the same fingering works an octave lower.