G'day stigweard,

IanC has it basically right ... except that, a good player - on a good whistle can get the top notes of the second octave plus 3 more ... with some trickier fingering (taught to me by a flautist). This is helpful when you need thos extra notes to play in the upper octave - useful for getting over loud and high instruments (even if it doesn't always make friends!).

Anyway, the Irish style of whistle is built around the 'D' whistle, playing in the keys 'D' and 'G'. You only need other whistles for playing with people who don't believe God wrote it ALL in 'D'.

Regards,

Bob Bolton