PB+J wrote:
I'm wondering if a better whistle would make a significant difference. I'm not a snob and don't need anything fancy, and yes practice is more important than the instrument, that is always and everywhere true. I'm impressed with the Dixon, that you can get so much fun out of a piece of plastic tube, but somethings are hard--tonguing in the low register produces squeeks, and half holing on the low register is kind of not happening. Is that just a low whistle thing? Or will a better whistle make a difference?
Hello and welcome to the forum!
If you like the dixon, I don't see a huge reason to upgrade just yet. Yes, to a certain extent, lower whistles tend to "squeak" more due to either not completely covering the widely spaced holes, or slight over-blowing. Practicing better breath control will help solve the latter, but you probably already figured that out

. In the case of half-holing, it may help to have a whistle with somewhat larger holes. I never have needed to half-hole with my friend's dixon, so I wouldn't really know how good it is in that regard.
As far as other whistles go, the possibilities are endless! Some posters here at C&F really like Susato low whistles (more plastic instruments). But of course, there are other higher-end options. For example, Ronaldo Reyburn makes fantastic whistles of all different keys. I'm sure other posters will give more great suggestions.
Cheers!