How To Better Use The Sensitivity Setting On A GPZ 7000

[flakmagnet]

Is there anyone out there who is willing to explain a little more in depth about the Sensitivity setting in the GPZ7000 and how works in relation to the other settings? 

Or perhaps point me to an existing discussion?

I don’t feel I know enough to use it correctly and I know it's obviously important.

Thank you in advance.

David

[mn90403]

David,

If you go to the top of this forum you will see a search engine.  I used it with the following key words:

7000 sensitivity

I got 42 results which included some of the very important threads on this forum which deal with your question.  A couple of the results will not apply but I think you will find lengthy discussions on sensitivity and volume limits, JP's conservative settings and Steve's super hot settings to name a few.

These results will answer questions most of us didn't think of asking.

I hope this helps.

Mitchel

[fredmason]

when in doubt use less rather than more...

fred

[flakmagnet]

Hi Mitchel and Fred,

I will take a look Mitchel - I thought I had used the search before, but must have not put in

the right search words, and Fred, as always, short, sweet and to the point.

Thank you both.

 

[Steve Herschbach]

There are two types of Gain or Sensitivity settings. One type boosts the actual transmit (TX) power of the detector. The other type boosts or amplifies the receive (RX) signal. The GPZ 7000 Sensitivity setting is the second type. That being the case increasing the sensitivity is not actually making the machine more powerful. You amplify signals from nuggets, but also from ground noise and electrical interference (EMI).

Ground setting controls directly affect the signals being generated. One ground setting may cause certain hot rocks to create signals. Another ground setting may eliminate those same hot rocks. Increasing the sensitivity in the first instance will make those hot rock signals and gold nugget signals louder. In the second instance, there is no hot rock signal that can be increased, so increasing the sensitivity control will not make those hot rock signals louder but will boost the response on a gold nugget. The Gold Mode and Ground Type are primary controls as they determine what the detector will or will not detect. The Sensitivity or Gain is a secondary control that amplifies the signals generated.

The audio settings,  Volume, Threshold Level, Threshold Pitch, Volume Limit, and Audio Smoothing all also act in their various ways to change how you hear the signal after the fact. They are less about changing the generated signal and more about customizing the sounds for your particular hearing. People still play one against the other however, lowering one while increasing another.

The main problem when you dig into the details is that THERE ARE NO MAGIC SETTINGS. Different ground types, hot rocks, gold types, and background EMI call for different primary settings. Then our own hearing and brain signal processing call for different secondary control settings.

Primary controls like ground type are actually simpler in my opinion. If you have a certain pesky hot rock, and one ground setting really lights it up, and another eliminates it, it is obvious with a bit of experimentation which setting is best.

After that however things get messy. What we all want really is a detector that is dead quiet, and then gives a loud, unmistakable beep on a gold nugget, and nothing else. People often strive to reach this ideal level of perfection. The problem is that we all discover that a perfectly quiet detector gives up certain signals, typically the weakest signals. The Threshold control is an easy example. Many people do not like listening to a detector that makes a constant noise. Just turn the threshold down until the machine is like a coin detector - quiet until it goes beep. Most nugget hunters however live and die by the threshold and feel lost without it. It is those faint threshold disturbances that signal a very small or very deep nugget.

Games then develop. Lower the Threshold but increase the Sensitivity is an example. It is like putting your foot on the brake while increasing the pressure on the gas pedal, with the great benefit being you can't burn up the brakes. You can still have your silent machine while boosting some signals that may have been lost, but finding the magic combination depends on what signals the primary controls are creating for you to modify in the first place, and that depends exactly where you are detecting.

After years of going over this with hundreds of detectors and thousands of people I have come to understand it really is more about our ears and brains. We all have different combinations. We all have different ears, that is fairly easy to understand, and so the threshold setting you find too loud I may find too quiet. It normally just needs to be set as low as possible while still being audible, but that setting may vary due to our hearing. The second part is more to do with our brain. If you hate hearing a noise all day, you may want to set the threshold to just below where it is audible. I may want to set it where it is just barely audible. That may have a bit too much waver in the sound for some people as the ground varies, so they will raise the threshold even more in an attempt to smooth the signal.

Which is correct? An engineer can tell you from a technical standpoint, but they would be wrong in my opinion. The trick to prospecting is in the end more mental than almost anything else. For most casual hunters it has to be enjoyable. If it is not, it is a burden to be borne, and we all can only bear a burden for so long. In my opinion the detector has to match your personal style in the way that makes you most comfortable and most likely to persevere and continue detecting.

My brain and my style demands constant audio feedback. In theory I want a machine to be perfectly quiet and only make a sound over gold. Forty years of detecting has taught me it does not work that way for me. I like to have the machine deliver constant audio feedback, and so at a minimum I need to have a constant threshold tone. I like to hear faint ground variations as I go. Each detector has its own language, and apparently I have a brain that from long years of detecting has been trained well in these languages. People hear noise, I hear the symphony. It does not matter that much that I have poor hearing - I fix that with the controls and headphones, etc. What matter most to me is getting all the audio into my ears and to my brain, where the real work occurs. EMI makes one noise, ground makes another, rocks make something else, but with time it is the nugget signal that stops me dead in my tracks.

Many people when coin detecting just want the machine to beep. Others want a couple tones. Most will balk at more than four tones. I prefer what is called full tones, which on my DFX means 191 different tones. I also do not like rejecting targets, but prefer for them to just have their own tone. It is all music to my ear, and I literally experience all attempts to reduce raw signals as a deadening of information to my brain. Critical information is being withheld and I am not happy. Too put it simply, if my machine is dead quiet, I feel deaf.

That is a long explanation of how I detect. I am at one extreme. Another person will be at the other far end, trying hard to make their machine dead quiet unless over a nugget or a coin. In between we have the vast majority of people, seeking their own perfect combination that works for them. None is actually right or wrong - it is what works best for them.

I am the renegade on this one because detectorists with more of an engineering bent will insist that no, running too noisy is bad, or running too quiet is bad. From an engineers perspective there is indeed a perfect signal to noise ratio for any given circumstance that is correct, and anything else is incorrect. The problem as I have found it is trying to impose one style of detecting on a person with a different style is hammering a square peg into a round hole. What matters in my opinion is to put very many hours on your detector while learning what every control does by way of experimentation. Then use that knowledge to develop settings that work best for your own situations and detecting style. Reading stuff like this is a very good start but at the end of the day it is like learning to play the guitar by reading about it. To learn and get good with a guitar requires constant practice and a detector is no different.

I almost never discuss specific settings, but did so by publishing my Steve's Insanely Hot GPZ 7000 Settings. I kind of regret doing so now. The problem is people latch onto this stuff like it is some kind of gospel. Then you get Lunk's ZED Settings and the debate begins, which is "right" and which is "wrong". The answer is Lunk's settings are right for him, and my settings are right for me, and both of us would change them in a heartbeat if we thought it would be beneficial. More importantly, neither of us would ever advocate just using some settings gleaned off the internet as anything more than a starting point for your own experimentation, to find what works best for you in given locations depending on your own detecting style and preferences. Using some setting off the internet is like buying a car and then getting on the internet and asking which gear setting and throttle setting combination is best. It all depends on the road and the driver.

The key thought I want to leave you with is that you just need to be in the ballpark. Detectors are actually pretty forgiving. The most important thing is to work on getting into good locations and practicing good prospecting habits like good coil control and long hours of detecting. Things like that have more impact on the gold you will find then the chase to find the perfect setting. Most nuggets I find to this day I would have found with a wide range of settings and indeed with many different detectors. You have to get the coil over the nugget, first and foremost.

Well, way more answer than a simple question asked for, and maybe I just confused the issue. That's what happens when you give me a cup of coffee and put me in front of a keyboard in the morning! Below it says "using the highest stable sensitivity setting will achieve the best performance" (emphasis added). Or go back to Fred's answer above if I have thoroughly confused the issue.

[Norvic]

No magic pudding for sure, tis as Steve says a mental approach, buggered if I know a formula that helps one arrive at best settings for them, haven`t found one for myself yet, but in short.......... Freds nailed it, Jps recommended it but bet he fiddles just a wee bit too. Steves Insane, Lunks, Bogenenes, manual GB etc etc they all work.

                       

[Steve Herschbach]

People confuse good settings with good prospecting skills. I find gold so people want to know my settings. Maybe my settings suck, and I am just good at getting my coil over gold nuggets. I actually would tend to argue that more than claiming I am a settings wizard. That is another reason I hate to get into specifics because I am darned if I can say my own settings are even what is best for me. My own opinion is that I am sloppy on settings and succeed mainly though hard work. My technique boils down to crank that baby up and start swinging! JP knows far better than I what makes for a good setting given any circumstance.

[Rivers rat]

Thats a very good statement!!!!:

"People confuse good settings with good prospecting skills."

Steve Herschbach 2017

[Rivers rat]

9 minutes ago, Steve Herschbach said:

People confuse good settings with good prospecting skills. I find gold so people want to know my settings. Maybe my settings suck, and I am just good at getting my coil over gold nuggets. I actually would tend to argue that more than claiming I am a settings wizard. That is another reason I hate to get into specifics because I am darned if I can say my own settings are even what is best for me. My own opinion is that I am sloppy on settings and succeed mainly though hard work. My technique boils down to crank that baby up and start swinging! JP knows far better than I what makes for a good setting given any circumstance.

I agree 100% with you........

 

RR

[Norvic]

The Z has a reset function that returns it to factory default settings, those settings are as good as any if not better to get you up to speed with the Z. A great fail safe set of settings that get gold no doubt and you will not be be far off by just sticking to them, at least until you have many hours behind the Z. ML knew what they were on about when they made these the default settings.