The material itself makes the sound. The pot or call body amplifies it. You can take a plain piece of slate and make it sound pretty good by just cupping your hand around it. The striker should be mated to the individual call. I' ve made corn cob strikers by sticking a cedar arrow shaft into a corn cob. I try it on the slate, and keep cutting off the shaft until I get the right tone. It has to vibrate just right.