I took a pipe cleaner and passed about 1 inch of it down through the window, took the rest and coiled it out of the way, around the barrel of my old Gen.
Poof! Extremely quiet whistle that plays in both octaves.
Wouldn’t do this to a wooden whistle…I don’t like metal near the blade… but its another easy way to practice while the baby is sleeping in the same room, while spouse is watching TV, etc.
I’m not sure this would record using my cheapy built in mike, but I’ll see if I can get a pic and clip.