Posted by vent on March 30, 2002 at 02:20:53:
In Reply to: Popping Valves posted by TubaFrank on March 30, 2002 at 02:09:14:
This is caused by the difference in air pressure, due to cooling, of the air in your slide chambers and in the tuba's main column of air. A vacuum is released when any valve is depressed.
Ask around about "venting" your valves. If this sound really bothers you, venting your valves will completely stop it without any detrimental effects.