GPZ Volume Limit

[Jonathan Porter]

14 hours ago, Andyy said:

ok guys, I appreciate the input.  Apparently I misunderstood the manual.  To me it almost made it sound like it rescaled the volume based on the limit.

Reason I had asked the question is that I used to run the GPX 5000.  First thing I noticed on the nuggets I found with the GPZ (running conservative settings) is that you would hear volume rise on some gold targets when you ran over them.  I found this strange but I learned to listen for this.   It was very obvious on the GPZ and I don't remember that on the 5000 so much.  Another difference is that the GPZ threshold seems completely different than the 5000.  The 5000 threshold would always stay the same fullness and sound but just get louder or quieter.  Not so with the GPZ.  Threshold gets fuller (busier) as you increase the value.  It's a different animal or seems to be anyways.

Just trying to understand a little better what settings do what.  For me, in my area, I now know that the bulk of the adjustment will be Sensitivity, Threshold, and Volume.  

Hi Andyy, the reason the GPZ is a different animal is down to a number of factors.

• Better EMI and Sferic rejection compared to any other detector made by Minelab before.
• Super D coil which manifests its signal response differently and also handles ground signals differently compared to a mono coil.
• Factory preset for Audio Smoothing (Stabilizer) is equivalent to 15 on a 5000.
• More aggressive Tx.
• Exact control over Rx sample times thanks to ZVT.

The most obvious difference to an experienced MPS user is the audio of the GPZ, it is very quiet but also busy at the same time. Target responses are subdued because of the coil design but so is the ground response. Also the threshold is demonstrating more information about the ground rather than being constantly affected by sferic and EMI noise, so now you can actually hear when the coil is passing over magnetic gold bearing soils. 

If you want to understand why the threshold and general detector behavior of the GPZ 7000 is so different to MPS then place the detector flat on the ground in an area with no EMI, go into the settings and  select Audio Smoothing OFF and listen to the threshold volume, after a minute take the Audio Smoothing from OFF to High (High is the Equivalent setting of 10 FP on the GPX 5000), notice how the detector sounds really quiet and Smooth? Audio Smoothing on 10 (Eqiv to High on GPZ) is baseline for the GPX 5000 and even then it still suffers from EMI, whereas the GPZ can easily run on OFF but there is a corresponding increase in threshold and Detector Volume, this is because you can easily work with the GPZ unfiltered thanks to major improvements in its electronics allowing you to tap into the full amount of target information of the detector. 

However that extra unfiltered information means you have to relearn the way the detector behaves from a volume point of view yet at the same time come to terms with the ground cancelling effect of the SuperD coil. The coil runs quiet, the detector electronics run quiet, but ZVT is aggressive. That is why I always advocate conservative settings if you want performance/depth, let the electronics do the work, don't hamstring the detector because it sounds too quiet on target responses, come to terms with the more subtle way ZVT/SuperD behaves, the information is there you just have to learn how to recognize it.

JP

[mn90403]

2 hours ago, Jonathan Porter said:

I always advocate conservative settings if you want performance/depth, let the electronics do the work, don't hamstring the detector because it sounds too quiet on target responses

Thanks again.  We're listening to you and Bill, and Kevin, and Lunk, and Steve, and Nenad, and Chris, and many more ...

[Andyy]

8 hours ago, Jonathan Porter said:

Hi Andyy, the reason the GPZ is a different animal is down to a number of factors.

• Better EMI and Sferic rejection compared to any other detector made by Minelab before.
• Super D coil which manifests its signal response differently and also handles ground signals differently compared to a mono coil.
• Factory preset for Audio Smoothing (Stabilizer) is equivalent to 15 on a 5000.
• More aggressive Tx.
• Exact control over Rx sample times thanks to ZVT.

The most obvious difference to an experienced MPS user is the audio of the GPZ, it is very quiet but also busy at the same time. Target responses are subdued because of the coil design but so is the ground response. Also the threshold is demonstrating more information about the ground rather than being constantly affected by sferic and EMI noise, so now you can actually hear when the coil is passing over magnetic gold bearing soils. 

If you want to understand why the threshold and general detector behavior of the GPZ 7000 is so different to MPS then place the detector flat on the ground in an area with no EMI, go into the settings and  select Audio Smoothing OFF and listen to the threshold volume, after a minute take the Audio Smoothing from OFF to High (High is the Equivalent setting of 10 FP on the GPX 5000), notice how the detector sounds really quiet and Smooth? Audio Smoothing on 10 (Eqiv to High on GPZ) is baseline for the GPX 5000 and even then it still suffers from EMI, whereas the GPZ can easily run on OFF but there is a corresponding increase in threshold and Detector Volume, this is because you can easily work with the GPZ unfiltered thanks to major improvements in its electronics allowing you to tap into the full amount of target information of the detector. 

However that extra unfiltered information means you have to relearn the way the detector behaves from a volume point of view yet at the same time come to terms with the ground cancelling effect of the SuperD coil. The coil runs quiet, the detector electronics run quiet, but ZVT is aggressive. That is why I always advocate conservative settings if you want performance/depth, let the electronics do the work, don't hamstring the detector because it sounds too quiet on target responses, come to terms with the more subtle way ZVT/SuperD behaves, the information is there you just have to learn how to recognize it.

JP

JP - thank you so much for taking the time to clearly explain the GPZ in your response.  I now see that I truly need to understand that I am not just hearing noise, I am hearing more information than I ever have before.  I think a lot of time and practice will help me with this.