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.
I have had this problem recently except it happened when switching gold or ground modes. I was switching back and forth to check target signals and lost all audio. It has happened twice and both times i have had to power off the Z to get the sound back. 🤷♂️
I have also noticed that my buttons don’t react that fast. I could fly through the buttons much easier if it would not take a full second or two to switch modes or select things. Is this normal? I have no one to compare this with. I had my GPS fixed under warranty and asked to have my screen changed out since it was scratched, in the process they replaced the front panel, I could have swore it worked faster before they put a new one in. No warranty now.
Maybe a hard restart or factory reset is in order and reinstall the firmware? 🤷♂️
I have had GP machines from the Extreme to the 4500 and nothing has EVER broken despite thousands of hours in the field being banged around, in the back of my pickup and on ATVs over rough trails.
I noticed that my GPZ has started rebooting and loosing it's current setting whenever I lay it on the ground. I have used one of Docs protective covers since I bought it.
I took off the cover and found this:
It appears that one of the pins that holds the battery in position has sheared off likely causing the reboot issue:
Luckily the broken pin was still in my big Minelab protective bag:
I'll try to epoxy it back on and treat the detector as if it is made of glass from now on. I'll admit that I have occasionally let it drop to the ground from a foot or two when going to dig a target. An apparently very bad habit I acquired when using the GPs. No more..
I'll see if I can fabricate a pad for the broken stand since I don't see this part available from ML separately.
I bought the machine used with about 10 hours of prior usage, so no warranty for me.
Just posting this so you guys won't have the same issue.
I’ve done a bunch of research online and I just can’t seem to find this. Does anybody know if there is a detailed video on each of the menu items/settings for the GPZ along with examples in real world environments? I realize that when I’m out in the field now, after continually reading this forum, that I kind of stick to the same settings that I’ve been using for a long time (except for changing between high-yield and general, as well as normal and difficult). It’s winter time, I am bored and I’d like to learn more on my GPZ 🤣🤣. Even if this is not a YouTube video and it’s some thing I can purchase I’d be willing to do that as well!
For years I ran the GPX 5000 Threshold setting with a faint audible level by following the book; which is condensed as follows;
Through a process of dynamic noise compensation, Smart Electronic Timing Alignment (SETA) ensures that the threshold stability is improved and maintained, allowing you to operate the GPX 5000 with maximum efficiency under all conditions.
Threshold is the constant audible background hum or noise produced by the detector.
On the front panel rotate the variable Threshold control to achieve a very faint but still audible noise level. It should be smooth with only minor fluctuations.
The Threshold is your reference point and lets you know what the coil is sensing, whether it may be a target, ground noise, or electrical interference, so it is important to set the threshold so it can be heard. When a target is detected, the Threshold changes in volume and pitch. Listen to the threshold carefully. Concentration is an important part of detecting. A very deep or small target may only cause a very small change to the Threshold noise.
Listening for a target signal with a high level of Threshold noise would be like trying to hear a whisper within a crowded noisy room. A high Threshold may also be uncomfortable to your hearing.
If the Threshold level is set too low (less noise) very soft target signals, from small or very deep targets, may not be heard.
It is important to reset the Threshold level as conditions change. For example, your ears may adjust to the low levels of audio after an hour or so, or the conditions may have become windy.
So here are my concerns;
With the GPZ 7000 I find it difficult to achieve the low quiet hum of the GPX 5000. I get the trying to hear a whisper within a crowded noisy room effect. The constant high noise level makes it difficult to listen for small changes that would indicate a small shallow or large deep nugget. So I tend to run it far below the default setting of 27. And much of the time I run at a setting of 1.
Another problem is related to the control differences between the two machines. The GPX 5000 has a simple variable Threshold control with no numbers to be concerned with.
The GPZ 7000 has digital values which appear to be inverted in function. Attached is an edited illustration from the GPZ 7000 manual that displays my view or understanding of how it should be described.
By Robert Eaton Jr
Hey everybody. I've been working my butt off to try to get ready to go find gold.Sometime seems like one step forward two steps back. A week and a half ago I was at the bottom of gold hill outside Virginia City, testing out the GPZ in the gold monster with my wife and kids, and when we put all the gear away I had my keys on the minelab vest, and stupidly locked them in the back of our car right at sun down. Being off the beaten path, and having to work had no choice but to smash my rear window to get the keys and get my family out of there. Just so happens that rear window is more expensive than my windshield at 500 plus dollars :-(.
Had to look of finding a free spirit Odyssey 45-in tent for only $2,000 near San Diego. Went down and picked it up, only to find out that the so-called towing Springs that I thought I ordered, and we're actually tihuan springs for a golf, and not the towing Springs that I thought. My mistake ordering them, now my car sags, and I've got a cough up another $160 and change the Springs myself. Times money. To make things even better, on the way back through the Mojave desert my heater core went out. Fortunately it's got a CPo warranty, unfortunately I can't trust the local dealership so I have to drive to Sacramento to have the dealership fix it, luckily it's only 50 bucks. And that covers this sway bar bushings too which are bad.
Yesterday I spent all day delivering doordash checking out Auburn and a little bit placer County. Forest Hill road and some other spots. Found an awesome mining store in Auburn. I like to get back today to metal detector it caught a land where I saw people excavating for a new home in placer County. I've got to work my butt off to pay off these bills, I hope I could get one or two hours.
I had went to Cold Springs to get some Paydirt with my wife from the bedrock that was exposed. So far I found tons of iron. Bringing it home to our kitchen, where I spent about an hour and a half learning to pan for the first time. With a five bucket gallon, it took me about a good hour to find a good rhythm. Wow am I a slow panner:(
I'm working on it, ordered some classifiers, and realized I need to get a sluice box or something to make that process go faster. I totally don't have any cash left to do that though...
So I also wanted to figure out how to make my GPZ and gold monster operate better where there's tons of iron. Sitting in bed right now I was just trying to set my machine with Steve's super hot settings, which apparently were not as hot as the ones I was running, when the ultimate nightmare happened.
Not even dressed, GPZ in my arms, I can see a gray line going down the center of the screen. Un freaking believable. I hardly used my GPZ yet. Not the hundreds of hours required. I've never dropped it I have no idea how this happened. Every free second of my day I try to spend looking for gold. there's no way I could afford to part with it for a couple months to send it to Australia. I'm hoping there's some way to have it fixed we're able to fix itself. Has anybody ever seen it a grey line in their display?
Now my f75 LCD is worse than my GPZ, and my poor GPZ has a line through it... I never let it go in lower than 15-20°....