GPZ 7000: Threshold Vs Sensitivity Vs Volume Vs Volume Limit (with Discussion On Audio Smoothing, Coil Control, Range Of Motion And Manual Ground Balance)By afreakofnature
Hey All. I have been researching this last month or so throughout Detector Prospector, Minelab's Knowledge Base and TreasureTalks so that I can take my skills with the GPZ to the next level and I think in order to do that it involves these 4 settings: Threshold, Sensitivity, Volume and Volume Limit. A lot of forum members talk about these comparing and contrasting, but none really give you a "How to." How do you go about adjusting these to reach perfection, to reach that perfect ZVT zen.
Conclusions that I have read are that: it just depends on what you want to hear, or how you hear what is coming out of the detector. OK, but I think it is more to it than that, and if you don't understand what these controls do how can you really achieve the best results.
Keeping these setting the same. Noise Canceled. Gold Mode: High Yield. Ground Type: Normal. Ground Balanced with Semi Auto. No filters - Audio nor Ground Smoothing. Lets talk about how we start.
Here is what I have researched and summed up describing these controls. These are my "interpretations" based on everything I have read and I think I really have a grasp on it now. This information and dissemination of it came from everyone here, and I mean everyone! Huge Thank You!
Sensitivity: aka Gain. Control of the INPUT "strength" of a "sound wave." You don't actually control how "sensitive" the coil is. ZVT is ZVT, that is the tech we are using In order to understand these controls I think of it like a "sound wave". What you control is the "sound wave" coming into the machine. Too much gain and you over modulate the sound wave, cause distortion, and increase the "noise" level. Too little gain and your "sound wave" is decreased (like making it a flatter line) maybe allowing large "sounds" to come through but in return lowering the "noise" level and small "sounds." In Sensitivity is where you want to produce the "perfect sound wave" coming into the machine. You want that sound wave to just barely reach below a distortion level to get the best "sound or tone"
Threshold: This is how much of the "noise" level you want to hear. It kind of acts like a bottom or "noise" filter. Increase threshold (lower number on GPZ) and you filter out more of the "noise" level as well as small "sounds." The opposite is to lower threshold (increase number on the GPZ) to filter out less of the "noise" level and hear smaller "sounds."
These two setting should play off of each other so that you can achieve the "biggest window" for the ZVT "sound wave" to operate in with the least amount of "noise". Some people use a 20 sensitivity and a 7 threshold. Is that the biggest window they could achieve? Some do a 15 sensitivity and a 27 threshold. Is that the biggest window they could achieve? How come you could not do a 1 sensitivity and a 53 threshold? Nobody has ever commented on that. Boost it? Probably not a good idea. I don't know, never tried. Food for thought, but I hope you get what I am saying about that.
In my eyes these two controls are where you should start. Achieve the biggest "window" that ZVT can work with. If you minimize the window you are not taking advantage of the full technology. In turn you are probably not finding the smallest pieces you could achieve or the greatest depth on targets. Don't limit ZVT, maximize it to its full potential. Open the window as far as you can for the ground/mineralization you are in.
Now on to Volume and Volume Limit
This is where I do not have the best grasp on these controls, even after all the research I am not sure if I am describing these correct. So many people play off of these and have different explanations. This is what I "think" they mean.
Volume: aka Audio Boost. Control of the OUTPUT "loudness" of the Threshold and Sensitivity window that you just created. We are told that this acts like an audio boost and that increasing this by one is like increasing Sensitivity by 2, etc. I don't think that is a good way to describe it, at least for me. What I think Volume is doing is increasing the loudness of the "window." Than includes the "sound wave" as well as the "noise" associated with it. If you can not hear the targets you want after adjusting your "window" above, then you need to boost the audio. Doing this though will increase what you hear in "noise" and I "think" this is why some describe this as equivalent to increasing Sensitivity but it is not. The "window" has already been set with your Threshold and Sensitivity, what volume does is change the OUTPUT "loudness" and there by multiplies how big the window is ("sound wave" and "noise"). This allows you to hear hear more, but more of EVERYTHING, in affect increasing overall loudness. This is why it should be used "conservatively." Start at 1 and work up until it is where you "like" hearing it. This is the part that should be subjective to each individual and their hearing.
Volume Limit: The Big Mystery. What does this do? How does it help me? Some say that this is actually volume. Some say this is what you should adjust to hear targets better. Some say it is just there to not blow your ear drums off if your volume is set to high. My questions are: Does this affect the "OUPUT" signal or the "INPUT" signal or both? Why would I want a Volume Limit? My thoughts on this...... I think that Volume Limit sets the MAXIMUM Volume (Audio Boost) "level" that can be used. I don't THINK it limits the Sensitivity. So this is an OUTPUT control. Therefore if you set the Volume Limit high you would get a higher (louder) incremental step with each number in Volume (Audio Boost). If you use a lower Volume Limit, you would have lower (less louder) incremental steps in Volume (Audio Boost). So if you want more precise control of your Volume (Audio Boost) you would set a lower Volume Limit. The trade off is maximum loudness. If you need to hear things louder you are going to have to raise your Volume Limit and then adjust your Volume (Audio Boost) accordingly. My thoughts are that people think this actually raises the volume but in the end if you keep Volume (Audio Boost) at 8 and increase Volume Limit, it will get louder per se because you just raised the the maximum loudness level there by increasing the loudness steps for each Volume (Audio Boost) number. Make sense? It does to me, I hope I am right otherwise I am gonna have to relearn this all over again 😉
Well now I need feedback from you all. Am I out in left field on all of this? Am I spot on? Or do I just need some minor tweaks? 🤣
AND if you have the desire to help some, could as many folks as possible make a video of them adjusting these settings to achieve a perfect balance? These are the videos that are missing on YouTube, etc. We see tons of people digging up gold but not many at all on "How" they use and set up their machine. This would be huge to see. You don't have to make a fancy video, maybe just have someone with their phone over your shoulder while you go through it. This would be a huge boon for a lot of people, including myself. Especially us that have to stay in all winter and have to wait to test their own theories. 🤣 So any help in that regard please post! OR if you already found some vids, please share. I have tried every search I could to no avail.
Anyways many members on here have said it before. You need to learn your machine. Its only one aspect of being an expert detectorist. I know I am not there yet cause it sure looks like I am still trying to learn my machine. The rest for me seemed to have come easier, researching locations, reading locations, putting the coil over the gold, etc. Now I NEED to revisit a bunch of locations where I got the easy gold by just using preprogramed settings that I learned when I just started. I started detecting at the SDC level. Turn on and go. I never had a GPX so comparing to the old never helped me. I am part of the new school of detectorists and I don't want to be ignorant by having less control. I want to take control. Its time to achieve ZVT zen and see what was left behind. Its time to level up.
So I'm still trying to milk the same cow 😄 I figured until it stops spitting silver on me, I will continue to ask for it. Long day at the beach 8:30-5:00, but the weather was decent, as I dress well for the cold. I'm getting to be a delicate flower in my advancing years 🤔 I'm using the GPX all day for this hunt and digging select areas and removing all iron so I can hear the deep targets.I hit a patch that started producing exclusively wheat pennies, so I knew that the chance for silver was very possible. It did produce some silver but the ratio was mostly pennies. Moving over just a bit, the wheats turned into memorials and the clad followed as well. Not a bad day with 8 silvers, but I worked harder than usual for it.The beach is slowly sanding in and the easy stuff is gone. No gold again, but switching the timings on the GPX did start getting me a lot of nickels, including a handful of Buffalo. Jewelry was missing as usual, but the spoons sure weren't lacking 🙄 So here is everything I dug. Lots of junk too. It was great to get out and enjoy the hobby.
Yet another spring like day today. Started out relatively warm, about 48. I decided to do some scouting on land I haven't visited as yet so I will know where to go in the future. In particular I was looking for another house that was in one of the fields back in 1917.
I think I found it. Found what looks like a drawer keyhole, and then an aluminum child's ring with no stone. It is very fragile and pretty mangled, but highly decorated.
I visited three separate areas, two yielded coins. I dug the 1967 quarter and a 1937 wheat penny. Went way out in the field near the river and found an 1867 Indian head. It was very difficult to find the date but I did. In the area that had no coins I found one small colonial button, it appears to have a backstamp but it is unreadable.
Not bad for just walking around at random, really coin shooting.
Another fabulous weather day here. Started out at 32 degrees, ended up about 63. I had a forum member special guest who may or may not identify himself, but he did a lot better than me. We started out on an old un-hunted landing, visited a very trashy point nearby, and finished up back at the landing and in the farm. 8 hours for me! Total blast. I like hunting alone but it's nice to have an esteemed visitor.
Top down in the photo:
Ford hubcap (I think) but certainly a Ford part. What I believe to be the "rest" of this vehicle is in the woods nearby. This little cap was a surprising 32 on my Equinox. Edit: Definitely a model "T" hubcap. Not sure what the "w" means. 1917-21.
Some sort of work animal tack, it's solid brass and rings like a tuning fork when dropped. Looks like it snapped off of a screw or bolt. Rein guide?
Cool brass buckle, a 26, some sort of white metal object with some decoration, an unidentifiable whatzit that was a solid 15, another "river queen" Indian head penny, an 1888 Indian head (it was tough to get a date off that one - still might not be right), broken tombac, a "D" buckle from the extremely trashy point, and yet another thimble, this one mashed flat. We left the point because it was just insanely signal-rich, and nothing we tried could help that. Apparently hunters eat their lunch there and bury the trash.
Hope this doesn't bore y'all to death. Don't think it will if the guest chimes in! One more day this week outside and then it's gonna rain for 4. Guess I'll have to get some work done around the house. Borrowed a new toy to play with, more later.
By Wendell Clark
I got out today for about 4 hours. A couple of old locals told me of an area near a WW2 air field that had civilian housing when the base was in use. During the 50's the county rented the cottage bungalows out. Small wood structures that were built on pier blocks. They were sold off and taken down by the early 60's. Looks to me to be a 10-12 acre area that had maybe 60 small units. Lots of junk but the area has not been razed. Looks like I have a new area to fiddle around at.
Now, wouldn't it be nice to find something like this!