I attempted to use them for many years without success in my youth. Hunted in dark timber in Maine, New Hampshire. NJ, NY etc.
About 15 years ago I was hunting the Tidal flats on Padre Island when I spotted a really nice Buck on the flats over a mile away. Absolutely no cover between us. I could have walked a couple miles back and circled around him when I remembered I had my useless grunt call.
It turned out to be one of my most memorable Kills.
I started grunting and I could see through my Binocs he was interested I'd call and he'd walk toward me about 100 yds and stop. I must have had about 15 cycles of me calling and him slowly moving toward me and stopping
When he was about 300 yds out he began to trot towards me. When he got about 75 yds away he stopped and was staring in my direction. I was lying in the mud behind some cat tales. I decided he was close enough and closed the deal
Watching that deer for about 1/2 hour coming and stopping never sure he would make the distance was so exciting and the rush was amazing.
I have tried the technique often but have never been blessed with the same result. I do appreciate the one time it worked