When I make them I take a dremel and thin the bones from the inside. Seems to change pitch to a get that 2 tone note. I love making them. I’m no artist but made this one last year for a good friend. I usually clean and cook the bones then hang on to them till someone takes an interest in mine then I’ll make them one. I find that thinning bones and playing with overall length drastically chances tone. I work then till I get the sound I’m after.