I'll give this a lash...I run in pro zero disc 40 with iron audio off, even still, I will get signals in the high 30's, along with the tid showing iron targets below that...I probably should be running 35 disc. for gold chains, I generally turn on the Pro and push and hold disc and count to "10" which maxes out disc at 40...yes, its quite a strange machine, depending upon what the iron is like in the area, the tids can be all over the place on good targets, I dont mind, it really nails me some good stuff, I'm only using the Pro in the water, and scoop everything scratchy, nasty and solid signals anywhere from the high 30's on up...those low 40's soft signals like a piece of foil are things I focus on..all solid mid range, rings hit like a train on this thing! I have not tried any settings other than these in over a year.
Mud