By Steve Herschbach
The Minelab GPZ 7000 audio Smoothing function was directly derived from the Stabilizer control used on the GPX series. From JP at http://www.detectorprospector.com/forum/topic/715-gold-i-found-in-victoria-with-the-gpz/?p=6424
"On the subject of Audio Smoothing: Off on the GPZ = 20 on the GPX 5000, Low equals 15 and High equals 10."
JP at the link referenced obviously prefers Smoothing to be left off. Some people are experimenting with higher audio smoothing settings combined with either hotter Gold Mode settings or higher Sensitivity settings or both. I think this is a good thing so do not go thinking it is "wrong". There is no right or wrong per se, it is all about what works for each prospector and their personal tolerance for noise or the lack thereof. Experimentation is good.
I thought it would be informative to copy what the GPZ manual (page 66) has to say about the Stabilizer control. Warning: the GPX Stabilizer control is backwards. The highest setting if 20 is the off position. Lower numbers increase smoothing. So the GPZ at off is same as GPX at 20 (off). Note that the GPZ High setting is the same as the GPX default setting of 10. The default for the GPZ 7000 is Low Smoothing which is the equivalent of a setting of 15 on the GPX.
One final note. RX Gain as referred to on the GPX is the same as the Sensitivity control on the GPX.
From the GPX manual:
I guess I should say that my preferences tend to follow JPs - I run with audio Smoothing off under nearly all circumstances. But I wanted to make this post to create a thread on the subject as it is very clear people are having success with other ways of thinking and again, I like out of box thinking. Lunks settings at http://www.detectorprospector.com/forum/topic/830-lunks-zed-settings/ are at the other end of the spectrum. I also liked Jason's observation on the subject at http://www.detectorprospector.com/forum/topic/827-minelab-video-gpz-7000-ground-type/?p=8276
I hate being the guy asking for help on the forum. But, I'm really struggling and hope some of you with more experience on the GPZ might be able to share some insight.
So, here's the scenario. I have what I think is an old equipment pad I've been working. I've nicknamed it my "trash patch" since it is just hammered with trash, probably why it doesn't appear to have be detected much even though close by areas have been beat to death. I found my first nugget in there with my GPZ at about 8", The problem, so much trash I couldn't even keep a single target under the 14" coil. I went back this week and spent 2 1/2 days (sun up to sun down) with my GB2 cleaning about a 2500sf area of trash. I can't begin to know how many targets were removed, but I can tell you my legs are so sore from that many squats I can barely walk today. Once I got the area clean, I was super excited to get back over it with the GPZ and see what I could find.
And, here's where we get to the help part. This entire pad has basically been built with about 3" of crushed hotrock. I thought getting the trash out was the biggest issue, but it wasn't. I can't figure out setting on the GPZ to get through the top layer. Either it just wobbles and whines all over the place, or you choke the settings down so hard it won't pick up anything. I can't find a working medium. Short of racking and shoveling 3" of rock off this area, which moves way outside the bounderies of enjoyable hobbie for me, I'm not sure what to do.
Anyone have some detector settings I might try, or other ideas would be greatly appreciated.
Attached are 8 little micro nuggets I pulled off the surface cleaning trash with the GB2. Everything I have got more than 2"s below the rock layer has been larger.
I'm not sure if it's coincidental but since the update I've run into a number of areas that cause a strange oscillation on the GPZ.
Basically, I can set the coil on these pieces of ground and not move it at all and it will just go "wee-woo-wee-woo" constantly and loudly as if there is a target underneath, it never balances out, manual or auto. Rebalancing over the ferrite does not seem to affect it, wether the ferrite is over that spot or away from the spot.
At first it was small spots and I thought it was EMI related, but now I've found entire washes that do it, yet the next wash over is fine. I was inclined to think it was due to salt, but there is so little salt around here that I went ahead and tasted some of the dirt (yep) and it wasn't salty. Usually I can taste salt if its bad enough to interfere with my machines. These washes have a lot of black sand and a lot of banded iron formation chunks laying about. usually running in normal and switching to difficult takes it away for the most part but sometimes it's still there.
Just odd that it never balances out. Has anyone else run into ground like that before? Most bad ground won't sit there and oscillate if you stop moving the coil even if its bad enough to not balance out.
When the upgrade first came out, a lot of ZED users were reluctant to change. I for one, thought if it was recommended, I should do it. I personalty believe it is more stable and more sensitive. I started to find very small pieces of trash in some areas that were virtually target free and some gold that was missed by some competent ZED users. The seven smaller pieces were found at Rye Patch and the others were found close to home in a very pounded area with all kinds of detectors. These were all found after the upgrade
I know Lunk covered this last spring, but I want to reiterate. This morning I got the classic faint mew tone, repeatable in both directions. This is the kind of tone we live for, I knew it was gold because I was out of the trash zone and it was obviously not a surface target. I was running HY, Normal, smoothing off, gain 12. I decided to play with the settings a little. First I switched to HY, Difficult, same sensitivity. The target was barely audible and I doubt that if I was in regular prospecting mode it would have been sufficient to stop me. I already knew it was there, so I had too much advanced knowledge. Then I switched to General,Normal, same sensitivity. The target was still very clear. I toggled back and forth, clearly the Difficult setting faded the target. Low Smoothing had little effect, but I was in very quiet ground. My conclusion, at least for this quiet ground in Sunny Yuma, use Difficult as a last resort. The nugget was about 5 inches deep.