Now that we can concentrate on the question at hand, I will share what I know about diaphram calls, such as it is.
But, it is like trying to teach someone to whistle, they have to experiment with it themselves to find the sweet spot.
Tr to hold your tongue on the sides, up tight against your upper molars with the front of your tongue pressing against the back of your bottom front teeth. Keep your mouth open partly,and don't force the air all the way from your lungs, in fact you should more or less hold your breath as you sort of hiss between your front teeth.
See what I mean?
It's better to work on it yourself until you figure it out.
As it happens, I used a diaphram quite a lot while in Africa the past two weeks. I gave one to Lochi when I left town, and he tried it without much success, at least while I was standing there. In his case, he was blowing much too hard, something not at all necessary. It's not like blowing up a balloon, you have to control the exhale, something like if you were trying to get someones' attention by going "phsst" real loud. Here I go again, it probably only makes sense to me?
What I have been using for the past year or so are the Primos triple tone , they might be called th4e professional model or expert, something like that? I have used the Lohman predator in the past, but I got some of these from Bruce Kennedy when he was having a closeout. They are good, I'd buy more. In fact, I need to locate some, because I gave away the only two spares I had over in Africa.
Like they always say...."hope this helps?"
Good hunting. LB