Hi all, did a quick test that may be of interest.
Using my standard 0.3 test piece, I buried it to max depth that I could get with a GPX5000 and 14" elite coil. This was in medium ground, on the mild side, the sort of ground where you feel it's overkill using Fine Gold, but still a bit noisy in Normal and Sensitive Extra. The detector was a little pushed, Rx Gain 13, Stabilizer 11, Target Volume 12, optimal settings for the spot. Comparing some various timings:
Fine Gold - clear nice little signal
Enhance - Still getting it, a little fainter
Sens Extra - getting it, but a weird signal
Normal - barely getting it, but had a dipping response, i.e low-high
Then powered up the Zed. In my normal high mineral settings, having last used it at Jupiter creek, basically got no response.
Knowing that I was now in an area with milder ground and less EMI, first thing to do is crank the Sensitivity. Upping it to 16, General, Difficult I was easily handling the ground, but the high sensitivity introduced quite a bit of noise that was messing with the target response. Drop of Sens to 15 and Smoothing on Low and the target was coming through quite clearly. I also tried the Max Sensitivity/Minimum Threshold trick and it worked, but I preferred hearing the threshold and Sens on 15.
Now, being in mild ground, I tried Normal ground type, and dropping the Sensitivity to 6. Here's how the gold modes compared:
Extra Deep - nothing
General - got a faint response, but dropping Sensitivity below 4 made the signal lost in the noise
High Yield - "whammo", very loud sharp signal response, even turning the Sensitivity to 3.
So in this soil, on that particular nugget, which is a very flat 0.3g bit, the two best setting combinations were:
1. High Yield, Normal, Sens 3 - 7, Smoothing Low (even tried High with good results)
2. General, Difficult, Sens 15, Smoothing Low
So, it's definitely worth spending a bit of time to find the right combo for where you are searching.
Nenad