Hello, I am new here. I have been watching this forum for some time and reading old topics, now I’d like to ask a question.
I have read every article on whistle-making and woodwind acoustics I managed to find on the Web, before I started the work. I got somewhere an aluminium tube (inner diameter 20 mm, wall thickness 2 mm). It was very nice, except for a scratched end. First I cut off this end and made an experimental “whistle” (er… ‘twas a 15cm long stub :o), so that I learnt how to work with the material. It made a sound quite well, so I took the longer piece and started to build a proper low whistle. This is how it looks now:
http://quenduluin.sweb.cz/jcf/ed.gif
It is not finished yet, that’s why the upper end looks so strange and unpractical to blow in 
The whistle doesn’t have any fingerholes yet and it is longer than is needed.
Well, there is a problem I’ve never heard about in beginners’ questions here: when I blow into the pipe, the tone it makes is one octave above the base tone - it is “automatically overblown”, while the lowest note is difficult to produce (it can be done but very slowly). 
There is another interesting thing about the pipe: it can “play” polyphonically :o) By a certain force of blowing, the base tone and the higher tone sound simultaneously. This gave me an idea about the root of my problem - my explanation is: the windway roof is not flat, thus the speed of the wind isn’t the same in the whole width of the windway. Somewhere the air goes faster to the blade, which produces the higher tone, somewhere slower, which is a source of the base tone. Er… what do you, more experienced, think of it?
Making the roof flat is not so easy, since the walls of the tube are thick. It can’t be done by pressing in a vise, nor by gentle tapping with a hammer: the circular cross-section of the tube would only turn slightly elliptical. And little cracks will appear on the surface. When I started to smite rudely the end of tube with a heavier hammer, I managed to make a Clarke-like square shape, but the tube, of course, was very badly scratched and beaten.
I think I will have to think off another method to change the windway cross-section. Do you have any suggestion? Or, do you think the problem could be sorted out by changing something else than the windway?
Thank you for your replies, and beg your pardon for my long text, certainly full of mistakes in the language.
Here is the largest list/source for making whistles/woodwinds that I know of.
http://www.shakuhachi.com/TOC-CM.html
I suggest Lew Paxton Price and Bart Hopkin’s books first.
Thomas Hastay.
Last year I believe that
fearfaoin
made some very nice whistles using the
plug and collar type fipple, and posted
pictures of their construction.
From reading your post I would suggest
that fearfaoins method is less destructive,
and less stressfull.
Search for the topic/pictures or send him a pm
for details. Most of them turned out quite well
IIRC, but it’s another method you might consider
using.
Aplogies if I’ve implicated the wrong person
but somebody’ll be along soon to put me right 
Hi Quenduluin,
Welcome to the fray!
This poliphony you are hearing is not a true poliphony!
Download the G-Tune software, or the Sound-Forge, or whatever, have a look at what the waves are doing - have a look at the fequency analysis - you will see the fundamental note (when you are playing softly) Is dominated by one or more of its harmonics. THe wave will show the true repeating pattern, but there will be a deap dip in the peak - the dip will be asymetrical, and if you look at the shoulders produced by those dips you will see some peaks, and in the shoulder of those peaks, more dips - it’s fractal.
What seems to be happening at the soundblade is that reflected pressure waves from the tube force the wind to flick-out over the blade, then as the pressure drops, it will flick-in to the tube causing a pressure wave to travel into the tube, reacting with the patterns there - it will travel down to wherever the air vents (a tone hole) this causes a sudden shock that reflects back up the tube to affect the wind at the blade again. Other stuff hapening in the tube will cause reflections back up to the edge - the net pressure under the blade determines when and how much the wind flicks-out or in. Keep in mind that these fractal/chaos cycles have ghosts - there is a big ghost at the bell note and at each open hole, they combine and compete - I suspect that there are pure “chaos” ghosts in there as well. I expect that “Chiff” is where the wind is unable to be either above or below the blade and simply splits on either side producing “no note” this no-note (pink noise = as the fequency increases the energy remains the same) is the initiator of the whole thing as the reflected echo is what defines the note - the reflections are not random.
Another thing that seems to be hapening is that the wind being flicked into the tube will migrate the “column” down the tube, so in-flicks will flatten the note - thus higher fequencies will become progressively flat as more volume of air travels down the tube due to the additional energy required to drive the note. Out-flicks will have the opposite affect to a much lesser affect.
It’s lots of fun to look at the waves. You are simply hearing the complexity of harmonics - to bring-out the fundamental, you will have to experiment with the bore-size and the dimensions of the sound-window/ramp angle etc.
Edited to say: I suppose the noise thing in chiff must be White noise - as the energy increases the frequency increases also - but it sounds “pinkish” to me. So it must be Whitish noise 
I expect a sound-blade that produces whiter noise will decrease the need for higher energy in the second octave, but it will also enhance the higher harmonics and make th whole thing more “shrill”.
Edited again to say: all this chaos in a simple pipe - this is what I call “goat” - and all the little black balls are “ubiquitous” - don’t step in the ubiquitous!!!
Plug and collar type fipple? Is it the design that is often used on PVC whistles? (http://science.univr.it/~gonzato/whistle/frombelow.jpg) And on some metal whistles too (http://impempe.mysite.wanadoo-members.co.uk/page3.html). Oh, that’s a very good idea! - one doesn’t make a flat windway roof to make it fit to a flat plug top and blade, but makes a round plug and blade to a round roof… that’s the way, thank you I’ll try it.
