If anyone can share their knowledge on whether there is an equation, scientific calculation or is it just trial and error on where the embouchure hole is created and how big it needs to be for a flute. I have a friend who has a polymer flute but recently lost the head joint completely. He is quite handy with his workshop skills and would like to have a go at making a temporary replacement head joint and he asked whether there was a science in the embouchure placement, the floor is yours ladies and gentlemen.
I appreciate he could always get in touch with the maker and order a replacement head.
When making my own PVC flutes I used a few resources…
The Flutomat javascript calculator: http://11wall-west.com/~ph_kosel/flutomat.html
This guide to making whistles was also useful: http://www.ggwhistles.com/howto/
And I carefully measured a Doug Tipple D flute.
The end result was that my original flutes do not precisely match either the Tipple or the Flutomat calculations, however it is very close. The theory cannot account for every variable in reality, so the only solution is to work it out on paper, make one, test it and then learn from that and make another. It’ll probably take 2 or 3 attempts to get a head joint you’re happy with.
Note the top embouchure hole is more circular, the bottom one is more like a flattened ellipse. Although they look and feel different, they have the same area (averaging the horizontal and vertical size of the hole) and sound pretty much the same.
Where it is created doesn’t seem to matter much so long as you leave enough space for the cork, however one thing I have noticed clearly is that the distance to the cork has a big effect. A close cork (near to the embouchure hole) makes it easier to play in the higher octave. A distant cork makes the lower octave stronger. A close cork also plays a little sharper.
What is the brand of your polymer flute? it would be better to measure from the original one than trail and error, the internal diameter of the head section is critical.on a normal pratten flute it’s around 19mm.
Here are two types of embouchure I’m using on my Delrin flutes, just for your reference.
The right one with longer edge is more powerful on low notes. while the left one has more crisp sound in the 2nd octave.
Thanks folks I will pass this on, apparently it was an M&E D Flute.