Posted by jeff miller on April 05, 2001 at 15:58:46:
In Reply to: Muscle problems posted by Concerned on April 03, 2001 at 23:33:15:
For a given amount of muscular tension in the embrochure, there will be a certain level of air pressure which must build up in the mouth in order to force your embrochure to open. The air pressure in the mouth then drops as the air escapes. The muscular tension becomes stronger than the force of the air pressure, and the lips close. This happens tens or hundreds of times a second and creates what we call a buzz.
You can play many ways - high air pressure and high lip tension result in a brighter, sizzlier sound. Lower air pressure and relaxed lip muscles result in a more bass heavy sound. This is the sound that we tend to associate with the American school of orchestral brass playing as exemplified by Arnold Jacobs.
Neither is absolutely right or wrong, (contrary to popular opinion) but the relaxed sound is much prefered in the US. It is also, I think, easier on the player.
Wobbly chops, especially when playing quietly or low, are often the result of an imbalance between the compression of the air in your mouth and the muscular tension in your embrochure. This is easily exacerbated by doubling on other instruments.
You need to remind your body how much muscular tension your embrochure needs to work with a given amount of air pressure. A good way to do this is to imagine that you are playing with a very slow, wide, fat air stream. Your embrochure will relax to work with the air.
Concentrate on the concept of the air stream, not on the physical mechanics of your body. To raise this process to another level, if you have a very well defined concept of a relaxed tuba sound (alla Arnold Jacobs) then concentrate only on that, and your body will adjust itself to produce that sound.
Hope that dissertation helps.
Jeff