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GPZ 7000: Threshold Vs Sensitivity Vs Volume Vs Volume Limit (with Discussion On Audio Smoothing, Coil Control, Range Of Motion And Manual Ground Balance)


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17 hours ago, Gold Catcher said:

This is a matter of opinion. I prefer to run sensitivity in more conservative ranges but keep all filtering off, whenever possible, and make adjustments to volume/treshold if needed. Works great for me.  An to quote the "man with the ring":

" High Yield Normal has oodles of sensitivity even with sensitivity set to 9. Do not be afraid to lower the Volume right down to 4 or 5." (JP)

I do the opposite, I run max gain and use a combination of playing threshold against the smoothing options.

The filters work great at clipping the eratic emi but keeping the target signal, you do however have to adjust the threshold up to compensate for the clipping.

Lower your gain though and kiss those deep faint signals goodbye😘

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3 hours ago, PhaseTech said:

I cover a few different combos of Audio Smoothing and Threshold in this video. 

Volume Limit I pretty much leave on 8 and never touch it. If I'm in a thick trash area and getting consistent loud blasts, I turn my enhancer down a touch and drop the Volume Limit to 7. 

If Minelab ever did another software update to the GPZ, then my No. 1 wish would be to just bring back the Stabilizer 1-20, and add threshold 26.5, but then I'm just one of those guys who loves analogue pots. The immediacy and fine tuning ability of them. 

Thanks for sharing, Nenad. This is a very nice demonstration. I usually shy away from high smoothing but I agree in your case this was a nice and clear target ID. A good example of how the Zed can operate in high EMI conditions and still be productive. 

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5 hours ago, PhaseTech said:

I cover a few different combos of Audio Smoothing and Threshold in this video. 

Volume Limit I pretty much leave on 8 and never touch it. If I'm in a thick trash area and getting consistent loud blasts, I turn my enhancer down a touch and drop the Volume Limit to 7. 

If Minelab ever did another software update to the GPZ, then my No. 1 wish would be to just bring back the Stabilizer 1-20, and add threshold 26.5, but then I'm just one of those guys who loves analogue pots. The immediacy and fine tuning ability of them. 

Nenad thank you for that video!  That had 2 of the controls discussed in this thread (Sensitivity and Threshold) plus a bonus with the Audio Smoothing and its effects on them.  Excellent!  Would love to see more of these.  Way more interesting than watching someone dig gold 🙂

I also like your seven rules and will need to read the full thread over on the other forum.  That forum I have not researched yet but I am also not a member.  Kind of scared 🤣

What are your thoughts on Volume and Volume Limit?  Do you a think I have their description correct?  Later today I am going to post up a visual to explain myself better.

P.S.  How is that requested "wireless" SP01 for the GPZ coming along? 🙂

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1 hour ago, afreakofnature said:

How is that requested "wireless" SP01 for the GPZ coming along?

(ears perking up…)

 

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10 hours ago, Gold Hound said:

I do the opposite, I run max gain and use a combination of playing threshold against the smoothing options.

The filters work great at clipping the eratic emi but keeping the target signal, you do however have to adjust the threshold up to compensate for the clipping.

Lower your gain though and kiss those deep faint signals goodbye😘

Agree there completely.

I believe the most important task to unleash the full horsepower of the GPZ is to make sure the machine itself is hearing the maximum possible number of target signals first. This is the basis of my entire detecting philosophy with the GPZ, and it sounds similar to your ideas as well. Get the information into the machine, as much target info as possible, then work the operator-side audio controls out as required. If the machine itself is missing a good number of target signals from the very start due to running too low gain, then no amount of adjusting audio will ever recover or hear them. This may vary if forced to run in Difficult, but I can't comment there, I can comment based on my experience though, though this isn't written to GoldHound since he already knows and prospects full time, as much as is it just putting this out in general.

  1. Most important is run in Normal any time possible.
  2. Next run in as high of sensitivity as possible.
  3. Control the mess with threshold and smoothing as needed.

Detailing #3 - I'll adjust Threshold down first. Then if I need Low Smoothing, I'll turn it on and bump Threshold back up to where I started to compensate. If not stable still, then I'll start bumping Threshold down 2 points at a time until I get something stable. If all that fails, then I'll finally lower Sensitivity by 2 points, and start the process again with normal threshold and no smoothing. Very rarely, almost never, have I ever had to drop below 16 Sensitivity.

I am guessing in general the difference between you and I is I will run a much lower threshold, as my THold max is usually 20, my max is lower than most people's minimum. :cool: Probably a lot more EMI around me since I'm much closer to cities though.

AFreakOfNature - it's not really possible to avoid discussing timings and smoothing while discussing Sensitivity and Threshold. They are all interrelated and used to compensate for each other. When the Ferrari goes in a tailspin in a tight curve, you don't slow down but you compensate by turning away from the curve (I might have that backwards, I'm not a racer haha) and also by accelerating, and that's how you keep driving fast but maintain control. The machine is all interconnected just like the GPZ controls are when running at peak performance.

Now I know many will disagree. But my feeling is that Volume and Volume Limit are not really fundamental in getting the detector to work at peak performance since they have less to do with what the detector hears and everything to do with what the operator hears. It's like how dirty your Ferrari windshield is, it only affects your driving it, but not so much the performance of the car. when the windshield is clean enough to drive, then good to go and not much to talk about. They are user-side settings. So, how a person sets them largely varies by the person's preferences (or hearing damage) themselves. Whereas the way timings, sensitivity are set depend largely on the environment and the gold and that applies equally to us all while detecting the same places, so more specific statements can be made than with relative settings like Volume. Thold and Smoothing are user side audio settings that border on machine side settings too in so much as you can use them to try to stay in Normal and higher Sensitivities and so all 4 of these settings are closely related and must be discussed together for any completeness.

Thold and Smoothing (worked together with Sensitivity) are the "turning and accelerating into the curve" to maintain top speed settings without losing control. Timing and Sensitivity are the engine and accelerator pedal.

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more on Volume Limit:

This is how I see Volume Limit.  It adjusts the maximum loudness (decibel) allowed out of the machine - OUTPUT.  You still have 20 increments to work with on the Volume (Audio Boost) control, no matter what you set your limit too.  It is just that each increment is exponentially greater based on increasing the limit you set.  I think this is why people see Volume Limit as a volume control because if you set your limit to 20 and set the Volume control at 8, but then lower your Volume Limit to 10 and leave your Volume on 8, you can see that it would be equivalent to a 4 back at the Volume Limit of 20.  Hence lowering the loudness heard.  It is completely relative to the Volume Limit set.  

image.thumb.png.18e5327957e2a65d549cc821a3722683.png

 

If Volume Limit truly was a decibel cut off.  Then it would look like this below.  Where if you set your Volume Limit to 10 then on your Volume control you would have no change from 11-20.  But this is not true, loudness does still increase, even with a limit set.  Therefore the way I see it Volume Limit can lower the maximum volume (loudness, decibel) overall, but does not cut it off.  Think about it,  if you had a loud target cut off at 45 decibels but kept raising the volume regardless then even the faint sounds (and noise) could be as loud as 45 decibels.  Making everything sound the same.  This does not happen.  

image.png.f4dbcd5937faae4f928fc3528daddd2c.png

In conclusion, like jasong has stated above.  This is all relative to YOUR hearing and not actual target strength (INPUT).

To me this is all making sense now.  I hope for others it is too, but I will still put my promo out there for videos of these controls in action 🙂  Keep'em coming!

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1 hour ago, afreakofnature said:

more on Volume Limit:

This is how I see Volume Limit.  It adjusts the maximum loudness (decibel) allowed out of the machine - OUTPUT.  You still have 20 increments to work with on the Volume (Audio Boost) control, no matter what you set your limit too.  It is just that each increment is exponentially greater based on increasing the limit you set.  I think this is why people see Volume Limit as a volume control because if you set your limit to 20 and set the Volume control at 8, but then lower your Volume Limit to 10 and leave your Volume on 8, you can see that it would be equivalent to a 4 back at the Volume Limit of 20.  Hence lowering the loudness heard.  It is completely relative to the Volume Limit set.  

image.thumb.png.18e5327957e2a65d549cc821a3722683.png

 

If Volume Limit truly was a decibel cut off.  Then it would look like this below.  Where if you set your Volume Limit to 10 then on your Volume control you would have no change from 11-20.  But this is not true, loudness does still increase, even with a limit set.  Therefore the way I see it Volume Limit can lower the maximum volume (loudness, decibel) overall, but does not cut it off.  Think about it,  if you had a loud target cut off at 45 decibels but kept raising the volume regardless then even the faint sounds (and noise) could be as loud as 45 decibels.  Making everything sound the same.  This does not happen.  

image.png.f4dbcd5937faae4f928fc3528daddd2c.png

In conclusion, like jasong has stated above.  This is all relative to YOUR hearing and not actual target strength (INPUT).

To me this is all making sense now.  I hope for others it is too, but I will still put my promo out there for videos of these controls in action 🙂  Keep'em coming!

Volume limit dose not modulate/compress the sound like your diagrams.

It mearly clips off the lowdest part of a signal that exceeds your setting what ever that is. Just like the Manual describes in its diagram.

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1 hour ago, Jonathan Porter said:

 On the GPZ there is also a lot of other things going on at the same time when you introduce Audio Smoothing and is why I always use that control on OFF and will be recommending ML on any future models to not include it at all and instead mirror the way the whole concept has been approached on the GPX 6000.

Thanks for your valuable comments, JP, as always! I find your comment regarding the history of the smoothing feature on GPZ interesting (that it is some sort of relict from the past from operators who are afraid of loosing control). When the info about the 6000 started to appear, I wondered why there is no smoothing anymore, now I understand why. I have always advocated to use sensitivity wisely and control ground/target response conservatively via volume and threshold function in Normal, or eventually going to difficult but leaving smoothing off. For me personally, this means that I can go only so high with gain, perhaps to about 10 in Normal and 14 in difficult without loosing my mind after 8 hours detecting, or without compromising to hear faint targets (a more serious matter than just loosing my mind...). At least in the grounds I hunt these gain numbers are about as high as I can go-on good days. But IMHO, this is enough power to hear just every target the GPZ is able to find as long as no filters/processing is applied.

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36 minutes ago, Gold Hound said:

Volume limit dose not modulate/compress the sound like your diagrams.

It mearly clips off the lowdest part of a signal that exceeds your setting what ever that is. Just like the Manual describes in its diagram.

I am not saying that it modulates it just sets the maximum loudness limit of the volume control (well maybe I am calling it modulation).  If it truly did clip it and you set the limit to 1 then crank the volume up to 20 everything would sound the same from high signals to low signals and probably all of the noise.  But if you set the limit at 1 and crank up the volume to 20 you actually do get variations in the loudness still.  I could be wrong but other pieces of electronics out there that has Volume Limit describes it in this matter, Minelab could be doing there own thing but that's confusing.   IDK I can't test this yet, maybe we will get someone to try this in a video.

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  • The title was changed to GPZ 7000: Threshold Vs Sensitivity Vs Volume Vs Volume Limit (with Discussion On Audio Smoothing, Coil Control, Range Of Motion And Manual Ground Balance)

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