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.