I’ve started making a copper high D whistle using the “Bloody Hand” instructions.
I have made the body 9-1/8" as instructed (I haven’t drilled any holes yet). When I check the tuning, I have a pretty close D in the lower register, but when I hit the octave, I have a definite D flat. The instructions do say that there may have to be a compromise between the two. If I shorten the body, the octave will be on, but the lower register will sharp.
My question is: Is it better to shorten the body so as to make the octave right on D or to leave it as is so that the lower register is more accurate, or is there another solution to this situation?
I agree with Dan On this one. This is your first whistle and will be made without a tuning slide. Flatness in the second mode(octave)can be compensated for by blowing harder to sharpen the notes.
If you must “tweak” this instrument,then make the tube a little shorter. The plans call for a slide-on mouthpiece that can be used as a tuner,at the risk of a bad seal.
note: The “phase-shift” of the key frequency (in cylindrical bores)between octaves is caused by increased internal pressure pushing up into the toneholes and the “unused” cubic area around the fipple plug face.This extra cubic area flattens pitch. Designing a conical bore of the correct angle,compensates for this phase-shift between octaves(ergo-Recorder bores).
[ This Message was edited by: Thomas-Hastay on 2002-02-05 16:36 ]
On 2002-02-05 16:02, Graphics Guy wrote:
Leave it be and start drilling the holes
pay attention to the 5th hole in particular
Also look at the fipple/blade area again
Dan
Dan,
Are you referring to the 5th hole from the fipple or the 5th from the bore?
Can you be more specific about paying special attention to this hole?
Thomas, At risk of opening another can of worms, might you be willing to tell us how to calculate a “conical bore of the correct angle” to compensate for this octave phase shift? Or perhaps direct us to a source?
Note: This request construes a solicitation of mathematical information which may cause some readers to break out in hives…
If, after drilling toneholes, the upper octave is still flat, you might try making a insert out of 0.015" wall brass tubing, using whatever size fits inside the copper (it may be somewhere around 19/32, but I’m not sure… go to your local hardware store and test). Inserting a 1" or so length in the bore above the top finger hole will change the octave-octave gap, sharpening the upper octave a bit (found this out by accident, while trying to devise an inner bore tuning slide without enlarging the body bore for a proper sized tuning slide). If this seems like a pain, I agree.
Dave
The common Recorder bore ratio is 5-4-3(average bore diameter of 4). I can post all the formulae for bore averageing but you can get all you wish in Lew Paxton Prices books found here…
Dave? Have you heard of the ancient Japanese flute called the Nohkan? “Noh” means “throat”. By reducing the bore diameter between the voicing and the first tonehole,a designer can increase acoustic coupling for a more efficient instrument. You can see a diagram of this here with a “glued up” bamboo conical bore…