The chatter I'm hearing in your video is iron contamination in the ground. Like Calabash said I run my upper ferrous at 10 in heavy iron. You also had your recovery speed at 4. Maybe try running recovery speed at 5 or 6 in heavy iron. You can also turn your ferrous volume down. I run my machine volume at 18-20 & my ferrous volume at 3 or 4.
Check out Iffy Signals video on YouTube ... Manticore in iron sites.
Check out Iffy Signals video on YouTube ... Manticore in iron sites.