I have brought a big buck in with a call at this time of year.
I was in a blind, and saw him, too far out for a shot. He was huge, probably the biggest deer I've seen while bow hunting. He was eating, and grunting, about every thirty seconds or so, softly.
Using a doe call first, a can call, he ignored me, even though the call is quite loud, he acted like he didn't hear.
Next, I tried the 'True Talker' and tried to replicate his grunt, very soft. This is easy with this call, as it is a quiet call.
First try, his head shot up like he'd been struck, but the big bugger disappeared into the old fence row, for his approach, and made me before any shot was possible. He was well within range, but the bush was way to thick, to even think about a shot.