Made a whistle pouch
General penny whistle or music discussions
I don't know where you live, but if you could visit an Irish session you could see and hear different whistles. You might also attend a dulcimer festival in your area. A lot of dulcimer folks also like whistles. Let's hear it for diatonic instruments.
Assuming the same brand and type of whistle, is there a difference in the hole spacing between a D and a C?