I finished this one last week. Came out very airy overall, but the sound is loud and strong. I made a wall around the window to cover it from the wind as I want to play this thing on the mountains where I’m going on vacation. Anyway, the wall somehow affected the sound, the lower notes became much stronger and more resonant, but the upper octave became very airy and “weird”… can’t find a better word for it, sorry. I made a soundclip anyway so you can hear it. I know I’m still plain bad when playing the low whistle but I believe it still serves as an example of how it sounds :roll:
[WTT]
Now, getting a bit more technical: The notes are a lot better balanced than in all my previous low whistles, but the finger stretch became longer at the same time… I’ve been watching other low whistles and it seems that the soundhole position/size is not “teorethically right” for flutomatic or TWCalc. I’m starting to guess that many or most whistlemakers are somehow “cheating” the results of these calculations to get more playable whistles (at least when finger stretch is concerned) and letting the player “tune” the note with breath control. I think I’ll try that on my next Low D. Any comments on this will be greatly appreciated!
[/WTT]
Ok, let’s go to the pics:
The wall is glued with epoxy
I made the windway a bit longer than the last one to increase backpressure even more. I think I’m becoming a backpressure adict…is there a Backpressure Addiction Disease? 
Finally, this is the soundclip.
As usual, any comment/suggestion/question is welcome! 