I've been experimenting with natural voice yelps for the last couple of decades, after being turned on to it by an old-time hunter in the Midwest who exclusively used his natural voice when turkey hunting. It is fairly low-volume, so I only use it once a gobbler is within 100 yards or so. I really like it for a fresh setup on a gobbler who hasn't been convinced by any of my other turkey calls, and/or using it late in the season on public land to give the gobblers a sound they perhaps haven't heard yet.
I know this won't win any turkey calling contests, but I have called in a surprising number of public-land gobblers over the years with natural voice yelps. To my ear inhale yelps sound more realistic, but I have actually called in more gobblers with exhale yelps. Any feedback is welcome, particularly from fellow natural voice callers!
Inhale yelps:
https://soundcloud.com/user-368849667/recording-2Exhale yelps:
https://soundcloud.com/user-368849667/exhale-yelps
