Interesting thread...
To add to my previous post, I just read where turkeys tend to respond more to higher pitched sounds...
I have also noticed that in years following poor production, I use a bit bossier/raspy call to more effect, and on years such as this following high production, maybe I get more responses from a cleaner higher pitched call?
Early in the season, hens tend to be quite vocal in the areas I hunt, and especially in the morning. I really try to hear what they are doing, and especially to what sounds and vocalizations the gobblers are responding to...
Later in the season, if I do hear a hen, or hens in the morning, I pay attention, and will imitate those sounds in prime areas later in the morning (hopefully when the hens are back on the nest).
We all listen for that gobble, but I am far more intent on listening to the hens and what vocalizations they are doing. If I do not hear any vocalizations, I tend to be far more subtle with my calling and concentrate on quiet contented clucks and purrs. Most of the time it does not work, but it has proven fruitful for me at times...