hidden slot?

Discussion in 'Trumpet Discussion' started by ltg_trumpet, Jun 19, 2009.

  1. mkmtrumpeter

    mkmtrumpeter New Friend

    46
    0
    Jun 17, 2009
    Colorado
    Following the overtone series, that partial is a Bb. I suppose if you adjusted your slides, it could be an A, but it you're using a different fingering then it's not a part of that overtone series anymore. Usually when I play an A above staff I find it helps to use third valve to bring it down a tad and I find it slots a lot better for me... but I digress. It's a flat Bb when played open.
     
  2. ComeBackKid

    ComeBackKid Fortissimo User

    2,858
    68
    May 11, 2009
    Yorba Linda, CA
    OK - this discussion has raised another question about the intervals. I found a chart on the internet which shows the note name, frequency, wavelength, etc. It is based on the A4=440hz spectrum. It shows that C4 has a frequency of 261.63 and a wavelength of 51.97 inches. I had read somewhere else (can't remember where) that a Bb trumpet has an overall tube length (open valves) of 52" (51.97?). Well, at first glance, it seems to make sense that C4, being the lowest harmonic would have a wavelength equal to the length of the tubing. But, since a Bb trumpet is playing 2 semitones below the concert pitch, that means it is not really playing the C4 note that matches the tubing length. It seems like I also read that a C trumpet has a tubing length of 48" but this does not match a concert C tone either (it matches C#). So now I am really confused. Anybody know what I'm missing?
     
  3. rowuk

    rowuk Moderator Staff Member

    Age:
    61
    16,611
    7,954
    Jun 18, 2006
    Germany
    The difference is that a trumpet is not a straight cylindrical tube.

    If you have ever blown a tone across the top of a beer bottle, you know that VOLUME has a lot to say about the resonant frequency of the instrument - drink more beer and the note gets lower. The rule is for cylinders, length is the primary consideration. For irregular shapes, volume. In a trumpet both.

    The bell also behaves differently at high and low frequencies. Buy 5 feet of 1/2 garden or aquarium hose, stick a mouthpiece in and check the intonation. You will discover that math and our ears have a different view on what is "in-tune". That is why I do not recommend electronic tuners. Add an old bell to that hose, and things get better.
     
  4. operagost

    operagost Forte User

    1,030
    543
    Jan 25, 2009
    Spring City, PA, USA
    When I drink more beer, eventually the floor gets a lot higher. :thumbsup:
     
  5. Sofus

    Sofus Forte User

    1,529
    17
    Jul 26, 2008
    Robin!

    Another question:

    We have learned that the mouthpiece end is the open end,
    and from the laws of standing waves in a tube this should
    mean that the wave pressure is low in a mouthpiece, since
    the wave pressure is low in an open end.
    Some people, who usually know what they talk about, say
    otherwise, so my question is:

    * is wave pressure low as I expect in the mp end?
    * if not, the why not?
     
    Last edited: Jul 4, 2009

Share This Page