Sure it's o.k. that all the calls don't sound the same, the aren't suppose to. Live turkeys all sound a little different also(young hens,old hens,jakes,mature toms) all have higher and lower pitched vocalizations. I in fact like several different sounding calls, you never know which call they might respond to on any particular day, therefore it is always good to try several and see which call gets the birds fired up. I also have found the slate type calls make the nicest sounding purrs IMO, but if I could I would like to learn to purr with my mouth calls, especially when the birds are in close so both hands are free and also no movement. The single D call is made by H.S. Strut, they make great calls, I especially like their Raspy Old Hen and Cuttin 2.5 calls. Good Luck, hope I was of some help.