My first bird fell to a gobble call. Set up on a field edge 20 mins before the rain moved in. When the rain came, the birds hit the field, but no where near me. They did not respond to some soft yelps, and they were moving away. In desperation, I tried a gobble on a mouth call. All three stopped and turned and headed in my direction. At 35 yards he went down.
I have a Knight and Hale call, a Hale Fire, but I'm not happy with the way I work it. Cannot get the rhythm down. But the mouth call works well. Move it as far back as you can tolerate and breathe "chicka, chicka, chockaw" and you will be surprised at the results.
I will always keep the gobble call in the arsenal.