I'm curious to learn more about how the fipple window size relates to a tone, for a given bore diameter and length This thread has been very helpful as far as width goes. As an experiment, I've created a wooden fipple head with a sliding labium in order to play with the window length, and make small adjustments to the step as well. I waxed the labium slide, and it's a snug fit, so there's no air leakage, but I still get some airiness in the tone, which is probably due to turbulence from the gap inside the bore.
I'll make a few more with different widths and share my results, for now here are some photos. I'm curious if anyone else has tried a similar experiment?
Movie of slide in action: https://imgur.com/THapPxj
![Image](https://i.imgur.com/oPNjvJC.jpeg)
![Image](https://i.imgur.com/yyb8uTk.jpeg)
![Image](https://imgur.com/YdLQRGj.gif)