Reverse leadpipe Vs non reversed leadpipe?

Discussion in 'Trumpet Discussion' started by the newbie, Mar 18, 2012.

  1. Sethoflagos

    Sethoflagos Utimate User

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    Two tuning slides came with my Wild Thing. one normalish, one round. If there's a significant difference somewhere, I never found it.
     
  2. Comeback

    Comeback Forte User

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    Interesting, Seth. All three of my Bb's have different shaped tuning slides with varying degrees of roundness. I really cannot tell much difference that I can associate with tuning slide shape.
    Jim
     
  3. Sethoflagos

    Sethoflagos Utimate User

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    Between, you and me Jim, I actually like a little bit of resistance. Seems to help with control at either end of the dynamic range, but it's a minority view here so let's keep it between ourselves, eh? ;-)
     
  4. trumpetsplus

    trumpetsplus Fortissimo User

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    Not necessarily. There is such little airflow through a trumpet that simple aerodynamics are not pertinent.
     
  5. Vulgano Brother

    Vulgano Brother Moderator Staff Member

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    Time for a quote from the famed acoustician with minor god status, Arthur H. Benade, just to mess with our heads.

    The more or less sharp bends that are made in the tubing of brass instruments to fold them enough for easy portability have an acoustical effect of their own. Even a pipe of uniform cross section acts somewhat like a flaring duct if it is given a curved shape. The small radius of curvature of the pie wall on the inner side of the curve acts as an outward flare, and the outside of the bend is recognizable as an inward or negative flare. This negative flare, being gentler, can only partially offset the acoustical effect produced by the positive flare of the inner side of the bend. The net result (as in a normal flare) is that the speed of sound is increased within the bend, and it also has a slightly lowered wave impedance (i.e., the duct acts as if it is a little oversize). Moreover, at the junction of curved and straight pipe segments one can have several kinds of wave reflections. For all these reasons instruments with many sharp bends act quite differently form their straighter cousins. The resonances can be shifted quite enough to be noticed in playing steady tones, and the beginnings of notes can be affected even more.

    Trumpet lore is that a shorter leadpipe encourages more of a compact sound and slots better, and a longer leadpipe provides more flexibility. Factor in bracing's effect on projection, and, uhh, it gets complicated.
     
  6. Comeback

    Comeback Forte User

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    Secret is safe with me, Seth.:shhh:
     
  7. robrtx

    robrtx Mezzo Forte User

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    :stars:
     
  8. Sethoflagos

    Sethoflagos Utimate User

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    Felt pretty much the same about that one myself, and thermodynamics is a fairly major chunk of my job spec! :dontknow:
     
  9. MiragePilot

    MiragePilot New Friend

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    "The net result (as in a normal flare) is that the speed of sound is increased within the bend,"

    This is fundamentally incorrect. The "speed of sound" is a function of the absolute temperature and specific heat of the fluid through which the sound wave is propogating, i.e. c = SQRT(kRT) where c = speed of sound; k = ratio of specific heats, Cp/Cv; R = universal gas constant, and T = absolute temperature.

    It is not affected by the geometry of the of the "vessel" that contains the fluid, as the article above implies.


    Peter
     
  10. Sethoflagos

    Sethoflagos Utimate User

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