Posted by Kenneth Sloan on March 22, 2003 at 11:49:02:
In Reply to: Mouthpiece posted by Questions on March 22, 2003 at 07:19:07:
I have a "back-of-the-envelope" model, based on my readings (but not a lot of personal experimentation). Don't make any life-altering decisions based on what follows.
Consider the mouthpiece as an amplifier. It takes the basic response of the instrument and enhances some of the frequencies. The amplification can be characterized by a central frequency and a bandwidth. As a general rule, (as is "obvious" to any brass player), small mouthpieces have a HIGH central frequency and large mouthpieces have a LOW central frequency.
If all else remains equal, and you modify *only* the size of the throat, then
increasing the size of the throat will move the central frequency HIGHER. It will INCREASE the band of frequencies which are amplified by the moutpiece, but at the same time LOWER the boost.
So...if you increase the size of the throat AND increase the size of the cup, then the central frequency (CC players - think of the G at the bottom of the staff) will stay in the same place - but the larger moutpiece will work over a larger range (better highs and lows), while at the same time giving a bit less boost in the middle of the range. Overall, just what a STRONG player wants. Conversely, a smaller cup and smaller throat will give more help in the middle range, but less help at extreme high and low frequencies. Perfect for the weaker player (who only has a 2 octave range anyway!)
So, a bigger throat give you *more* slots (adds some at top and bottom) but each slot is a bit lower. It also seems that the slots are WIDER - so the large throat/large cup mouthpiece is more steerable. Once again, probably good for the strong player, and not so good for the beginner.
All of this implies that a beginner should start with a mouthpiece with a small throat and a small cup volume, and "move up" to mouthpieces with larger throats and larger cup volumes (changing the two in lock step). Or, a player can vary the cup volume in the obvious way to emphasize the high or low range (at the expense of the other end). What is probably counter-intuitive to most players is that increasing the throat size tends to make the HIGH end easier (and vice versa). So...if you like your current mouthpiece, don't need help at the low end, and are trying to play the tuba-1 part on a BBb, you should get a reamer and bore out the throat. Sound familiar?
Again, these are my handwaving conclusions from amateur reading in the field. Correction by true authorities is more than welcome.