I made a couple that have a high squeak that is loud. It may have been a accident in production. I took two flat pieces if wood, 3/4" X 2" X 1/4" thick, sanded a dip about 1/32" deep midway on the flat of only one piece. Stretched a 1/4" piece of plastic food wrap between these wood pieces. Like having a grass blade between your thumbs.Securing the wood together is the tricky part. I secured one end by drilling very small holes through the end sandwiching the plastic strip. Then using brads (nails), cut and peened these. Do the same for the other end after adjusting for the sound by stretching the plastic. There! a custom call!
Go on predator masters and go under the custom calls section. I've had a few of those guys make me calls exactly the way I wanted them. Some of those guys are unbelievable what they can make a call sound like.
Theres a call named crit-r-call. For some reason it the only one I feel very comfortable calling with. I use it with a high pitch reed. They give you a number of reeds when you buy. I had the sond dog but lost it. I have the jr now. I also seconf the pred masters thing.