Steve's Insanely Hot GPZ 7000 Settings

[vanursepaul]

That's going to take some getting used to

[Steve Herschbach]

It depends on the mineralization level Paul. JP said "unless the surface mineralisation is Minimal." The type of mineralization JP is referring to is far more common in Oz than in the U.S. I have been fine letting my coil ride on the ground.

From the white paper at http://www.minelab.com/__files/f/266297/KBA_24-1%20ZVT%20Technology.pdf

"SATURABLE SOILS

In any of the above settings, it pays to swing the coil an inch or two above the ground surface if the soils are considered saturable (VRM). Saturable means that a detector ground balances well if the coil is raised and lowered down to about a few centimeters above the soil surface, and for the worst saturation, down to several centimeters, but not if the coil is swung up and down to a height lower than these saturation 'height thresholds' (e.g. Down to the soil surface). This is discussed if further detail below."

In other words, it it ground balances fine down to ground level, no problem. And then farther below it goes on to provide more technical details:

"In any of the above settings, it pays to swing the coil an inch or so above the soil surface if the soils are considered saturable (VRM). Saturable means that a detector ground balances well if the coil is raised and lowered down to about a few centimetres above the soil surface, and for the worst saturation, down to several centimetres, but not if the coil is swung up and down to a height lower than these saturation ‘height thresholds’ (e.g. down to the soil surface.) In addition, the degree of (VRM) soil saturation is considerably less for Difficult or Severe than Normal. As the metal detector coil is moved towards a soil, the transmitted magnetic field in the soil gets stronger. This causes a (very) small degree of VRM signal ‘saturation’ that happens to cause the resistive signal relative slope of the tilt to change. This is why the amount of VRM soil saturation is far less for Difficult and Severe than Normal. Soil saturation often requires the user to operate the coil several centimetres above the soil surface for best results."

I posted in even more detail about this in May at http://www.detectorprospector.com/forum/topic/970-minelab-gpz-7000-a-super-vlf-saturable-soil-tips/

The detector will tell you what to do. If the ground is making noise, slow down or raise the coil, or both.

[spencer]

The more I run this machine like a gold bug 2 the better it performs, ignore 99.9% of the noise it makes just as I do with a GB2 and listen for the 2 sounds it makes over metalic targets. I may dig a bit more ground noise than some but it has paid off so far.

[Gold Hound]

I used normal most of the time on the 5k as well.

I relly like a lot of ground information coming back at me!

Reading this ground info that everyone else calls "noise" can tell you alot about what is happening with the soil minerals.

This "noise" that I prefer to think of as "ground information" can actually put you on to auriferous ground.

I think people are inherently lazy and take the path of least resistance, in regards to metal detecting the easy option is to use the less sensitive timings or mode's.

People always talk about ignoring the noise as well, me I don't ignore any noise I absorb and filter every tiny noise the detector makes and let my mind filter the wheat from the chaff.

If you block out the info its not there to process is it?

[Swifty]

I like rockey road ice cream, I like a quite threshold, it allows me to hear very slight changes in what the  coil is passing over. Someone else likes vanilla ice cream, they like a noisy threshold. I keep reading the term used,  its giving them information on the ground they are swinging their coil over. Let me taste your ice cream! What is this information? I've had stony meteorites. iron stones. and lead that all sound like gold. I've had gold nuggets that sound like pull tabs. What am I missing hear?

[auminesweeper]

I like rockey road ice cream, I like a quite threshold, it allows me to hear very slight changes in what the  coil is passing over. Someone else likes vanilla ice cream, they like a noisy threshold.   What am I missing hear?

Yep, Don't let Ice Cream Get in to the Battery Compartment or it will start Playing Little RIchard's   Tutti Frutti,     

[Steve Herschbach]

On November 17, 2015 at 7:37 AM, Swifty said:

I like rockey road ice cream, I like a quite threshold, it allows me to hear very slight changes in what the  coil is passing over. Someone else likes vanilla ice cream, they like a noisy threshold. I keep reading the term used,  its giving them information on the ground they are swinging their coil over. Let me taste your ice cream! What is this information? I've had stony meteorites. iron stones. and lead that all sound like gold. I've had gold nuggets that sound like pull tabs. What am I missing hear?

I would put it the other way around - we like Rocky Road and you like Vanilla. Rocky road is rough and chunky and vanilla is smooth as can be. First off, nobody is saying you can tell gold nuggets specifically from all other signals. Yes, you better dig pull tabs, lead, and meteorites if you want gold! Those would all be gold signals. The discussion here is all about ground noise and hot rocks. And yes, I dig a lot of hot rocks and some ground signals now and then. Don't think there are magic "gold only" sounds.

Dale summed it up perfectly "I don't ignore any noise I absorb and filter every tiny noise the detector makes and let my mind filter the wheat from the chaff."

There will never be an end to this discussion because what works well for one person does not work well for others. We really are all individuals and our brains are wired differently.

The GPZ and Gold Bug 2 comparison is a good one. Both are very hot machines and can be run in similar fashions. You can take a Gold Bug 2 in all metal mode, and by using a combination of the Mineral setting and Sensitivity control seek to tame the beast. This would mean possibly using the Normal or High mineral setting and lower sensitivity levels in order to quiet the machine down.

I always run a Gold Bug 2 in Low mineral mode no matter what the ground is like, and the sensitivity is always at maximum. I ran it that way in Australia with no problem. What it takes is hours of listening to the machine and training your mind to learn what ground and hot rocks sound like and what targets sound like. It is extremely difficult to describe but genuine targets just sound sharper in general. Again, coil control is critical.

The GPZ is much the same and I would be very uncomfortable if the machine was running dead quiet and giving me no feedback on what the ground is doing under the coil. It is all music to my ears. When I refer to noise I just mean non-target sounds. Ignoring may mean not perking up on non-targets and we can easily get hung up on trying to place exact verbal descriptions on what is going on. The bottom line is some people are able to take in all these audio sounds and process them mentally. What others perceive as noise that drives them crazy is comforting to those who hunt this way.

In Chris Ralph's example he spoke of noise that drove him crazy and made the machine inoperable in his opinion. His assumption was I just could not hear it. Not true. I hear it but it simply is non-target audio information. The key thing is it does not bother me at all and it bothers him a great deal. The difference is in the mind.

There are some very, very good detector operators who would say this is all very, very wrong. They will advise tuning with the goal of seeking the quietest most stable threshold possible. I am not going to argue with any of that because I just do not believe there is only one way to get results with a metal detector. Most importantly I do believe we all have different capacities for listening to the sounds a metal detector makes and processing those sounds and that this requires different tuning methods for many of us. Trying to cram everyone into some one size fits all settings is a mistake in my opinion and I will never advocate that. Learning to use a metal detector well is a journey of sorts that takes time and dedication. I have likened it to learning a musical instrument and I defy anyone to learn how to play the guitar by reading about it on a forum. You will never learn to detect reading about it, you have to go out and put in the hours and dig the rocks and the nails and the bullets and the nuggets and always pay attention in the process to what the detector is telling you and teaching you. Experiment, try different things, different settings, and find what works best for you. But if your goal is to find gold others miss you better be willing to push the machine performance to the limits, and that will always mean accepting some level of signal response that is more aggressive than smooth and quiet.

In theory the perfect detector would just ignore the ground completely and just make good clean solid signals on gold, and metal detectors can be set up and run like that. It is when you are pushing the limits though that you find that by suppressing absolutely all sounds except for the sounds a nugget makes that an edge is lost. The GPX 5000 is a good case in point. People love the Fine Gold setting because it suppresses sounds from nearly all hot rocks. But the good operators know that Normal is more powerful, and that by running in Normal and being willing to dig some of those hot rocks more gold can be found. Sometimes it just boils down to a willingness to dig more signals that turn out not to be gold to find those other signals that turn out to be the nugget everyone else missed.

OK, I just thought of another way of looking at it. Imagine all the possible tuning options as ultimately setting an audio threshold. There is a range from where the detector is reporting 100% of everything it sees all the way down to reporting nothing. The most important thing is that gold nuggets and the ground signal/hot rock signals all overlap to a certain degree. Most nuggets do stand out and so the machine can be set to suppress all other signals and still produce a lot of gold. What gets lost is the borderline gold signals. Instead, you can choose to allow more of these type signals to occur. What the experienced operators know is that we still have not made detectors with processing circuits that equal the human ear and mind. In theory it can be done because there is something we hear that allows us to decide which targets to dig and which to ignore. The machines have not got there yet however and so almost all really good detectorists chose to hunt by ear rather than allow the machine to make all the decisions.

The same discussion goes on all the time with coin and relic hunters and the merits of hunting by ear using tones versus silent search discrimination. Anybody really good at using a DEUS or other machine to pull targets out of ferrous trash should know what we are talking about here. It can get into some real complex discussions - see http://www.metaldetectingworld.com/xp_deus_multi_tones.shtml for example.

If you set the machine to be completely quiet on all trash you can find good stuff. But almost all good operators choose to listen to all the targets under the coil and mentally process the information because the machines themselves just are not up to the task, and those are the operators that extract good finds that everyone else misses. Not everyone has the mental aptitude or patience to deal with all the "noise". It is just something that some people are better at than others. There is a guy named Keith Southern who would be a superb nugget hunter but he lives back east and so he pulls non-ferrous targets out of old sites covered with ferrous junk. Some people give him grief because they say nobody can listen to all that racket and stay sane but the guy simply has superb audio processing skills others lack. I follow his posts because his observations on finding things match up perfectly with my observations on using VLF detectors to pull gold nuggets out of ferrous trash. The methodology is exactly the same as what is trying to be conveyed here with the GPZ and ground/hot rock signals.

Well, I think I have run out of steam and beat that subject up as much as I can. I am just tripping over my tongue trying to express in words what can only be learned in person. Others can add whatever they can think of. I think it is obvious that the GPZ is still a new thing and new ways and methods are still being discovered for getting the best possible performance out of it. I sure do not think I have it all figured out by any means. The day I ever think that somebody shows me something new so I remain a perpetual student of prospecting and metal detecting.

[Norvic]

Wow, you covered it all, in particular the analogy to coin hunting. With all the discrimination features of the modern coin machine. It seems better to leave them off and process with ears-brain.

[Swifty]

Thank you Steve for putting up a good explanation on what was very confusing to me. 

I have one of those brains that will never make  sense of all the extra background noises.  Cant play the guitar worth a crap either lol.

But as least I have an idea what others are saying when they express that the background  noise is giving them information..

[jasong]

I agree to an extent, but the timings are there for the same reason the hardware and software filtering inside the detector are there and for the same reason we don't have amplifiers with 100x more gain even though we can easily build them. Noise is real and it will mask targets otherwise we'd have detectors that hear a 1 grammer at 10ft - we can make one, we just can't hear the signal in all the noise. 

There is a point where adding more ground noise doesn't add anything new to the conversation so to speak unless I'm missing something obvious here... There is only so much ground information you can get before it's not saying anything new in the noise, it's just getting louder. EMI increases along with it and unless you like listening to lightning or meteorites in the atosphere from 500 miles away, it's not saying anything useful. The usefulness is in increasing the noise so you also increase the target response as far as I can tell, but at some point there is diminishing returns and it seems to be part of a detectorists skillset is in determining where that point is at.

The human ear and brain perceives sound non-linearly - which is why the decibel scale is logarithmic. What that means is that a sound that is 10x louder really only sounds 2x louder to us. So volumes that are double really only sound like very faint variations to our brains. Same with frequency shifts (tones). Volumes or tones that only vary slightly are difficult for our brains to differentiate when the noise floor is raised to the same level as the target. There is also the psychological effect that I forget the name of, but our brains get "used" to repetitive senses and automatically dull them out - like how you get used to a smell and don't notice it but someone who just walks in does, or you get used to temperature of a cold lake after diving in, ears are the same.

Anyways, I guess my point is just that running full blast in some cases may be just as counterproductive as running in Fine Gold in places where there is no need for it.