Posted by Rick Denney on March 01, 2004 at 18:49:34:
In Reply to: Re: Re: Physics of Tubas posted by Educable on March 01, 2004 at 18:31:15:
The overall impedance of the system is the sum of the impedance of the horn, the mouthpiece, and your lips. The resonance peaks of horn-shaped instrument are actually fairly wide.
But if you have strong enough chops, you can always force a buzz at an unresonant frequency. The instrument won't amplify it efficiently, and it won't reinforce your ability to play it by giving that well-timed return pulse from the bell that makes the center of a note so obvious. When you do this, you've so constrained the resonance (vibration) peak of your lips that they cannot vibrate in any other mode than the one you want. Without the reinforcement from the horn, the sound suffers, but with those wide peaks there's almost always some collection of frequencies that will ring with any given buzz, even if they add up to noise.
Rick "who can't make sounds with resonance assistance from the tuba" Denney