I've not had much luck with the crow call, so I stopped using it. However, I hunt public land with pressure. I get them to shock gobble with an owl call in the morning, and later in the day high-pitched (aluminum or crystal) yelps on a slate.

If I catch a gobbler on the roost, I give him 3 subtle yelps. If he responds with a gobble, I repeat the sequence. If I stike one later in the day, I give him more of whatever he responded to.

I have killed most of my gobblers with 3 yelp sequences on a diaphragm.