Without the experience of playing many different whistles myself, I’m trying to understand the relationship between backpressure and how much air a whistle takes.
Does an increase in backpressure generally = decrease in volume? I have a NAF that has so much “backpressure” to it that I would pass out before I would be able to use all the air in my lungs… and it is very very quiet. OTOH, I have a white PVC low D on hand that is just a hog… it’s loud and clear and but I can play just a few notes before gulping in a breath.
I know all of this is subjective…
You’re pretty much there and it is generally-speaking true all other things being equal. To give you an example, Colin Goldie makes his Low D in three “flavours:” soft, medium and hard blowers each determined by the height of the windway. The soft blower has the higher windway, takes more breath and has lower backpressure. It has an open tone and is perhaps a little louder than the others. At the other extreme, the hard blower has a lot of backpressure but requires less breath. It is perhaps a little quieter and has a more muffled sound. Hope that helps. This (http://www.ggwhistles.com/howto/index.html) is a useful page for getting to understand more about how different dimensions etc influence sound and playing dynamics. Look under How To Get Your Favourite Sound.