I am under the impression that for maximum depth you need a sweep speed on the faster side. What influences your sweep speed and how do you tweak your settings on your machine? I have a DFX. I could be wrong because I'm new at this, but I believe my depth in influenced most by Gain, AC Sensitivity, Ground Filter and Swing Speed. I'm trying to understand this relationship and move beyond the factory presets. I have "Digging Deeper with the DFX", but I'm interested to know what other White's owners are doing to attain maximum depth. Any feedback is appreciated. Thanks for looking. HH. Matt