-Narrow flip holes and wider chambers (harder to "over blow")
Based on Fox 40 whistle 3 chambers design
-LP_LC NH version: lower pitch (around 3200Hz) and chambers with larger diameters than original Fox 40.
-HP_Fox_40_LC NH version: pitch very similar to Fox 40 and chambers with larger diameters.
-HP_Fox_40_LC NH 1.3 version: pitch even closer to Fox 40 and chambers with larger diameters. To print: do no use "Detect thin walls" (or any similar function) on Slic3r, use 0.2mm (give it priority), 0.15mm or 0.1mm for better results - any resolution lower or above has not been tested.
-Apito MK IV - just try it :)
I´m still developing its desgin, sugestions are welcome.
Perimeters, top and bottom solid layers: 4 or more.
Brim is recommended.
No need rafts or supports if printed by the mouthpiece.
After printed, for a better finish, remove any loose piece of plastic from the windcutter (knife edge).