Acoustics of palm key tonehole placement

Discussion in 'General Acoustics Discussion' started by jbtsax, Jun 7, 2015.

  1. jbtsax

    jbtsax Distinguished Member Distinguished Member

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    I have believed for quite some time that the reason the palm key tonehole placements are so low on the body tube as to cause the notes to sound extremely flat in the first octave (without the octave key) was to compensate for the effects of octave vent. In other words the farther the octave vent is from the note's natural displacement antinode (pressure node) the more adding the octave vent sharpens the note. Examples of the neck octave are high A and high C#. Examples of the body octave are D and G#.

    This belief was challenged the other day when I played the normally extremely flat D palm key D in the first octave and then overblew (overblowed?) the note to its 2nd harmonic. The 2nd harmonic was an in tune D3 and the pitch did not change when the octave key was added or removed. This seems to suggest that it is the body taper up to that point that produces the extremely wide octave between the flat D2 played with the palm and the (relatively in tune) D3---not the octave vent compromise position. Kymarto, can you help me out with this one. I'm baffled.
     
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  2. kymarto

    kymarto Content Expert/Moderator Staff Member CE/Moderator

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    That's a good question and I don't have a ready answer, but I'll bet it has to do with the fact that the tube gets shorter the impedances get weaker, so perhaps at that point reed effects start to come into play--that and perturbations introduced by the mpc definitely are in play in a shorter tube, since the "disturbed" part of the cone becomes a much higher proportion of the total tube, and mismatches begin to affect the register tunings.

    What has always interested me is the fact that short-tube C# needs mechanical correction to bring the pitch down in the second register on sop saxes but not on bigger horns. I think Nederveen might talk about that stuff but I am in China and not near my copy of his book.
     
  3. Mojo

    Mojo

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    My palm key D2 (in the first octave) is not very flat. I tune it to the long D2 after I warm up. If it isn't reasonably in tune there may be an embouchure and/or mouthpiece chamber volume solution.
     
  4. jbtsax

    jbtsax Distinguished Member Distinguished Member

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    I don't understand why palm D without the octave should need to be in tune since that fingering is never used. The C to D trill is done by keeping the C down and trilling the palm Eb. I would be more interested in looking for a solution to the flat middle C# besides opening the middle side key.
     
  5. Mojo

    Mojo

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    I would not say never. Paul Quinichette (vice prez) used Palm D and his primary D2 fingering. I only know this obscure fact because I saw him play several times as a kid attending free jazz concerts in Red Bank NJ in the late 70's.

    Some me classical sax players use the palm D2 to avoid the color change of jumping across the break for one note. They also occasionally use the long C#2 or C2 fingering.

    Some rock sax players use the long D2 fingering with the palm D open instead of the octave key. You can really honk on that fingering without breaking the note.
     
  6. Mojo

    Mojo

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    I think if you do have a solution to tune the palm D2, then the C# is not so flat. One could get similar results by tuning open C#2 to the long C#2.

    Try using a larger chambered mouthpiece and pushing it in farther if your short notes are flat.

    I actually had the opposite problem on my YAS-62 with a Meyer mouthpiece a few years ago. The short notes were sharp. By switching to a Vandoren classical mouthpiece with a squeeze throat design, I was able to pull out some to center the tuning better. I had been lipping the Meyer in tune for 20 years.
     

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