67GTA, I've experienced the same exact thing one a few properties in central NC. One in particular is horrible. Almost constant soil noise and when you go over a rock it's even worse. On this particular site, it's impossible to quiet it down by ground balancing...it just wont balance. It's an odd soil type, different from most of my sites (which are generally pretty crappy difficult clay) and it's very difficult to search in. Can't seem to dig anything deeper than a few inches. I've tried upping recovery, all of the 1-2 modes, ground balancing, and can not really tell any difference. One thing I have not tried that I saw mentioned in this thread is one of the single frequencies.
I manged to dig a musket ball the first time I visited the site (sounded mostly like iron) with my buddy who runs my old ATP. The ATP was running as normal, so I buried the freshly dug musket ball about 5-6 inches to see if we could pick it up. I managed to get a little bit of iron grunt swinging over the ball, and the ATP actually signaled a bit better than the Nox with a non-iron tone.
So, next time I try this horrid place, I am going to try the single frequencies to see if it will quiet it down. Might be a while, but I'll report back once I do.
