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I'm loving all the acoustic discussions lately (except the squabbling!). Learning a ton. Here's a question I haven't seen before: how does the laquer color change tone? Wait... wrong question. Let me try again:

Why does it seem that mouthpieces with high baffles limit your ability to manipulate tone using your mouth/throat? Does the baffle kind of "cut off" the sound waves in the horn from their resonances in your body, or maybe the baffle creates such a powerful contribution to the resonances of the horn (relative to the ability of the oral cavity and throat to voice notes) that you really can't change the average resonant output of the instrument anymore?
 

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I dont know the scientific reason but baffles speed air flow. Changing the oral cavity also alters the speed of air flow. My assumption is that high baffle pieces speed the flow to such an extent that it overcomes some changes in air flow that would normally be more pronounced in a lower baffled piece. This is not to say that one cannot shape the tone, it does suggest that it leans more towards a "Dialed in" setting. I could be 100% wrong but it seems as such to me. Im sure some of our more scientifically endowed members can chime in here.
 

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selmer 26 nino, 22 curved sop, super alto, King Super 20 and Martin tenors, Stowasser tartogatos
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For a given air pressure, the velocity of the air flowing past the reed and into the mpc depends on the size of the opening between reed and tip. The air moves faster as the reed closes, and when it is almost closed Bernoulli force then adds an extra closing force that accelerates the reed and closes it. The Bernoulli force depends critically on the baffle shape, and changes the steepness of the "flow-control curve" at a certain point when the reed is almost closed. So the shape of the baffle influences the shape of the flow-control curve, actually the way in which the reed oscillates. Benade doesn't get quantitative, but says:

"The fact that the flow-control characteristic curve is not straight (or, equivalently, the fact that the slope varies from point to point along the curve) is an indications that heterodyne effects can take place. It is this nonlinear feature of the flow-control behavior that leads to the existence of regimes of oscillation, in which oscillation is maintained by excitations taking place simultaneously at several frequencies."

I think what this basically means is that the way the reed vibrates can influence the strength of the partials, not to mention the feel of the whole instrument by changing how a pressure exerted by the player is translated into a certain behavior of the reed.
 

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Distinguished SOTW Member/Forum Contributor 2009
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My assumption is that high baffle pieces speed the flow to such an extent that it overcomes some changes in air flow that would normally be more pronounced in a lower baffled piece.
That's exactly what I feel and think.


So the shape of the baffle influences the shape of the flow-control curve, actually the way in which the reed oscillates.
Aha, interesting.
 
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