I'll chime in, the last 50 yards callas low as possible, loud calling has hung up more gobblers than any other reason other than calling too much, tone it down, you can be assured on one fact, if he's gobbling every breath, he's not moving much, when he's quiet is when he is moving, when he's moving don't give him enough reason to stop and gobble, the more he gobbles, the longer it takes to get it done the more chance of something bad happening (another hunter, coyote, etc.).
I call, low first, then loud till I get a response, the adjust depending on what that turkey wants to hear and the distance. Also I do not call to a turkey on the roost, had too many just sit on the limb till 9:00, then turn around and fly off.
RR