Re: Re: Re: B&S 4P

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Posted by Rick Denney on June 03, 2003 at 14:53:13:

In Reply to: Re: Re: B&S 4P posted by js on May 29, 2003 at 23:38:12:

Even Jacobs himself dismissed the notion that we fill up the instrument with air.

When I measured my YM and Miraphones, I found them to have about 2000 cubic inches of volume. That's 33 liters of air, or about ten of my lung-fulls before any of my actual exhalation gets to the outside world. Can you say "hyperventilation?"

By the way, the "YEAH" resonance that you describe doesn't happen immediately. It takes the time required for one cycle of the fundamental for the reflection from the bell to return to the mouthpiece, and that reflection, when it's in phase with the pulses we are sending from our lips, is what we call resonance. If we are playing an 8th-partial middle C (on a C tuba), we have to vibrate our lips, in time, eight full cycles before the resonance of the instrument helps us. Thus, you have to manipulate your lips to naturally vibrate that well-tuned middle C to initiate the note, and you have to do that no matter how good the tuba is. Air provides the pressure needed to open the lips to make a pulse, and when the pulse is over the pressure drops and our lips close again. The springiness of the lips works equally with the air quantity and pressure to produce the proper vibration.

Insufficient air forces us to do things with our lips (and cheeks, and shoulders, and belly, and eyebrows, and anything else we can think of) that are not effective in producing the proper vibration. We do those things much like a swimmer who is out of breath gropes for the wall at the end of the pool. The swimmer's focus on swimming is lost and replaced by survival, and swimming form usually falls apart. Likewise, when we manipulate all the wrong things to force a particular vibration even with insufficient air, the resonance behind the lips so that the tone is hampered. Good air is only conspicuous by its absence.

It seems to me that forcing a vibration slightly different from the natural resonance of the instrument would have a similar effect to an insufficient air supply--we would grope for anything we could do to get the right note to come out.

I seem to recall that Ren Schilke took a hacksaw to the main tuning slide of Jacobs's York because it played chronically flat in light of rising pitch standards.

Rick "who wonders why a tuba can't be designed to accommodate the whole range of common tuning standards" Denney

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