I want the low tone for iron, and the hi tone for anything over iron. Is it possible. IF YES, then would someone please explain how. I have been trying but when I set my tone frequencies and breakpoints, it keeps running my DISC back up. I won't the DISC at ZERO so that I can hear stuff under the coil. Un until now, if I set the DISC at zero, then iron has a mid-tone sound..Thanks for any help that you can afford me.