I do a bleat can and tending grunt in random order. I only have success when I do the tending grunt loudly. In my opinion, a loud tending grunt is the only way to bring them In if you want to see bucks. For years, I tried grunting softly with no success. The wind and trees must really damper how far the sound travels. Also, don't worry about the pitch. From what I've observed, deep grunts don't equal a mature buck and vice versa.
However, I think I'm going to stop doing this type of calling blindly. It works very well on my property, but the bucks often jump downwind to come into the call. This morning, I had a 120+ 8 pt come in to the call through thick cover behind me. I had no shot. When he was about 35 yards away he winded me (and I'm religious with scent control) and blew like he was on fire. I'm still sick about it.