Hi Guys,
In my use of the Infinium so far, I've been far more impressed with the dual-tone id than the use of the disc knob itself.
The dual-tone does not always give a correct id, but digging hi-lo tones does result primarily in turning up low conductive targets like gold nuggets, gold jewelry, pull tabs, US nickels, and such while eliminating most iron and steel. Not all, mind you, but most. Pieces of wire and hairpins read hi-lo, and masses of flat, rusted flakes of steel.
Supposedly a large enough gold nugget will read lo-hi, but I've tested up to 7 ounce nuggets and so far all have read hi-lo.
The dual-tone id really does seem to work at depth. On my last outing, a White's MXT located a quart paint can at just over two feet in a tailing pile. The MXT read it as a good, non-ferrous target all the way down. The same can read lo-hi on the Infinium all the way out to where it could barely be picked up at all. Frankly, I was a bit surprised when this was observed.
I've also been digging nickels at about 12" that correctly id hi-lo. My feeling so far is that the dual tone does work very well at max depths, and does a very good job at separating low conductive and high conductive targets.
The disc knob, basically increases the minimum level of conductivity a target must have to give a signal. Unfortunately it also seems to result in a direct loss of depth. So items at the edge of detection depth tend to drop out as this control is increased, regardless of their composition. This means that deep iron targets tend to drop out, and therefore are incorrectly identified as "low conductive".
Bottom line is simple. I've been using the dual-tone system a lot and have quite a bit of faith in it at this point for certain applications. But I pretty much ignore the disc knob now, as I have not seen that it really helps much on the targets I most need help with... those deep ones! The disc knob seems somewhat redundant on the Infinium.
Check the link below for lots more Infinium notes.
Steve Herschbach