For those of you that use the velocity of air...

Discussion in 'Trumpet Discussion' started by TrumpetMonk, Feb 11, 2010.

  1. rowuk

    rowuk Moderator Staff Member

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    Stuffy is a symptom. The trumpet needs a certain amount of inefficiency so that our air passes through the horn in intervals that keep us from suffocating, or running out of air too early.

    The other part of stuffy has to do with hearing ourselves. Everyone take their own favorite instrument and play in a nice sounding room. We get the warm fuzzies. Now take the same horn and go to some lake where there is a great distance between you and anything. Play the same horn and it is stuffy.

    Stuffiness is a combination of hearing and breathing. For environments without good acoustics, lightweight and lightly braced horns give the player more information back - at the cost of what the audience gets............ They are perceived as less stuffy.
     
  2. dhbailey

    dhbailey Piano User

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    To clarify whether the air goes faster or not, it's plain fluid dynamics -- turn on your garden hose without a nozzle, and the water simply falls to the ground as it comes out of the end of the hose. Then use your thumb to close off most of the opening, and the water comes out much faster, so fast that you can shoot it across your yard and hit someone on the other side. So, yes, the water is moving faster at the opening, but that increased speed keeps on moving way past the point of restriction.

    And to answer Rowuk's question about why we can hold the higher notes longer even though the air is coming out faster -- it's not the same amount of air, as Bobby Shew was quoted as saying. That restriction which gives the increased speed (the venturi effect) means that less air is flowing past that point, leaving more inside the lungs for a longer sustained sound.

    I agree with those who say that the arching of the tongue is a great visualization that helps people reach higher notes, but it is also doing something physical to the air making it possible to play those higher notes.

    faster air speed = faster vibration of the lips
     
  3. rowuk

    rowuk Moderator Staff Member

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    DH,
    your comparison is missing something important: the garden hose is leaking into free space in both instances. With the trumpet, the resistance changes with frequency. The "venturi" of the mouthpiece throat is MUCH smaller than your arch as is the venturi called "aperature" for most high notes. An additional "restriction" would not change the flow as it is already blocked further down in the system. "Cheater" mouthpieces have even smaller cups and throats further limiting possible velocity - but supposedly aid the upper register.

    I prefer to visualise the the resistance in front and behind the lips as raising their resonant frequency through a sort of compression. That gives higher notes with more pressure but less velocity and flow. It also offers an explanation why shallow cups "could" be of help if the breathing is together and why shallow cups do not work at all with some players - the vibrating part of their lips protrude too far into the cup. That increases the area (and mass) that starts the vibrations but is in the way of the small, light surface for really high notes.
     
  4. nordlandstrompet

    nordlandstrompet Forte User

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    Ah! Finally we have a venturi confession!

    Do the following trick:
    1: Take your mp, form your lips outside the rim. Blow, then suck.
    2: Turn your mp, form the lips around the shank. Blow, then suck.

    The point is?
    When the air is directed from the “cup side”, you will feel that the stream is less restrictive than from the “shank side”.

    So what?
    Within a very few seconds, a full breath will be blown through the narrowest point on the trumpet.

    3: Take your trumpet, form your lips around the leadpipe and blow.
    Within even fewer seconds, your full breath will be gone…..

    Now, put the parts together, form your lips outside the mp rim and blow.
    Still only a few seconds before the breath is gone?

    Play a low (under the staff type) C in forte. How many seconds before the full breath was gone?
    Play a G on top of staff in forte. Measure the time till your lungs are empty.

    The G on top of staff will of course last longer than the low C.

    And now, the controversy: The frequency of the G requires faster air than the C, but less volume. (litres/gallons per minute)
    The aperture of the lips is narrower for the G, and don’t need as “many litres/gallons per minute” as the C,
    but the speed of the air passing through the aperture is higher.

    The part that no one talks about:
    Standing wave…….resistance…….reflections…….

    As you now might have tried the tricks in point 1+2+3,
    you have discovered that there is not much resistance in a trumpet when
    blowing air through it, both with and without mouthpiece.

    My stone in the glass factory is that the air resistance itself has very little to do with what we feel as stuffiness.
    My take is (I’ve tried this one before) that the way the horn is shaped has most to do with how the horn feels.
    Out of alignment valves will not restrict the air column much, but will make a obstacle for the standing wave,
    which will be reflected back and make the horn fell stuffy.
    Mouthpiece GAP is a part of this story. Bigger GAP better slotting?
    Round tuning slides feels more open than a square angled?
    Water inside the horn make it feel more stuffy?

    Let the games begin…….
     
  5. nordlandstrompet

    nordlandstrompet Forte User

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    The part that no one talks about:
    Standing wave…….resistance…….reflections…….
     
  6. B15M

    B15M Forte User

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