At least, I think it’s chiff. Clarke whistles, chiff, yes? I finally visited a nearby music store and found a natural Clarke D and a Sweetone D. Since I had so few before, I am loving these whistles. The Clarke is hard… takes a lot of air, and I need more practice at it, but that Sweetone! It’s perfect! They’re different from each other, but more important, they’re different from Waltons! I figured if I started with a Clarke I might have some idea what I’m looking for next time I get whoa attacks. Thanks to all who gave suggestions. 