Digalicious

So why is it that in my high emi sites, the noise reduction on my Vanquish 540 and my Legend do nothing? Why is it that of the countless videos I've seen of those detectors, or the D2, Nox, etc, the noise pretty much stays the same after noise cancelling? I'm thinking noise cancelling only works under a rare emi situation in which the emi is only at one particular frequency (or something along those lines).

Well, what I have been doing at each high emi site, is burying my desired target very deep, and seeing what hits it best. Be it SMF with reduced sensitivity, or SF with maximum or close to maximum sensitivity.

No problem Jeff.

Due to winter, I haven't been able to hunt for 3 weeks now, and won't be able to for about the next 4 months. It's made me a little snappy.

So, would it be a true statement to say, "The more EMI noise reduction, the less sensitivity"?

Thank you for all the replies so far.

Is it actually true that one detector can reduce EMI noise significantly better than another? I mean, I would think that all noise reduction works on the same principle, so the effectivness of it should be similar from one detector to another. But, if some reduce the noise much more than others, then would it not mean that the better one is applying more aggressive filtering which means a performance loss? Or, could be outright reducing that "hidden" (for lack of a better term) sensitivity?

That all leads me to another question:

On a high emi site, when you have had to reduce the sensitivity to get rid of the noise, have you ever had to decrease it so much, that you could definitively say, "Wow, I'm really noticing a depth loss"?

Uh, no. On the other forum, I never got an answer to the question of, "What exactly is technically occurring when you run a noise reduction?". I'm asking on this forum, because this forum seems to have a lot more technically inclined detectorists.

 

Hello.

I didn't see a general detector talk forum, so I hope this forum is ok for this topic.

I own 3 detectors with emi noise reduction, and on all 3, it does little to nothing to reduce emi noise. I've also watched countless videos in which numerous types of smf detectors are very noisy due to emi, then a  noise reduction is done, and as usual, it does diddly squat. They end up doing what we do, and reduce the sensitivity, or use a single frequency.  SMF is so prone to emi because apparently, when the frequencies are combined and "added together", then emi noise from the various frequencies, is also added together and therefore the noise is exponentially increased. 

So, my question is: What exactly is technically occurring when you run a noise reduction? Does it filter out or reduce the sensitivity of the frequencies that are receiving noise? If so, why doesn't it work very well? Is it because if it worked well, then that filtering would significantly diminish the benefits of smf? Also, is it possible that if a particular detectors noise reduction works significantly better than a different detector, then it's because the noise reduction was achieved by reducing the "hidden" fundamental sensitivy? If so, that means you wouldn't see the sensitivity drop, but you would indeed lose sensitivity.

So what's up with all that?

 

43 minutes ago, Jeff McClendon said:

It’s not hard to set these detectors up with settings and frequency weighting that are really close. Swinging the coils with flat swings is also very easy so, not sure what you are getting at…………

What can’t be setup the same is the “starting point” engineered into these detectors for their built in recovery speed and target separation. Deus 2’s are obviously different from the Legend and Equinox.

 

What I'm getting at, is how even just a slight difference in certain settings can affect the ID when it comes to unmasking / separation. For example, let's take frequency weighting. You know that the Legend's Park M1 is weighted differently than the Nox's Park 1, and as such, the TID is often very different between those two when it comes to unmasking in nonferrous trash. But, so many do unmasking comparisons with those two modes, and erroneously declare one a winner.

The other issue is so many assuming that one detector’s default mid range iron bias setting, or mid range recovery speed setting is the same. Thing is, they are not the same, so the TID will be different.

My main point in this regard, is that the technology in detectors like the Nox, Manti, Legend, D2, etc, is fundamentally the same. More so, if all settings are accurately reproduced in these detectors, then the performance will be similar. If all the settings are truly matched with each detector, and one detector stands out from the others in an unmasking scenario, then it is most likely due to aggressive up averaging...which of course is detrimental in other scenarios.

 

Thanks for that Jeff.

How did you determine the settings were the same on each detector? For example, iron bias, recovery speed, and frequency weighting? Then of course, with such a test, the coil height and angle to the targets has to be identical as well.

Even if the settings were identical, one detector might up or down average more so than another detector. So, in one scenario detector "A" gives a better ID, but detector "B" gives a better ID under a different scenario.

59 minutes ago, Chase Goldman said:

  However, the holy grail is unlikely to happen using IB - being able to reliably differentiate gold from aluminum.

I've said almost the exact same thing many times. I say "almost" because I didn't say it was unlikely to happen with IB, but rather, I said it can't happen with IB🙂

With new technology, either that will be the next breakthrough, or a true imaging detector with enough resolution to show the shape difference between for example, a pull tab and a ring.

15 minutes ago, phrunt said:

The GPZ is a perfect example of this, using coils that are not controlled by Minelab gives it a quite dramatic performance boost, doing anything official and sanctioned doesn't give the same boost.  They are clearly holding it back, only by cutting the end off a coil to bypass the security chip can you realise the benefits. 

Hi Phrunt.

I don't know anything about Minelab's market share at that time, but I can see a company doing that if they had the majority of the market share. The more of a monopoly a company has, the more they can get away with such tactics.

With that said, my point was referring to breakthrough technology that would put all the competition out of business. For example, if a metal detecting company had technology that could distinguish between gold jewelry and trash, it would be profoundly asinine for them not to release it.

1 hour ago, PSPR said:

You haven't seen the improvements in the ground radar devices lately.

How does "improvements in ground radar" refute what I said?

Is there ground penetrating radar that will blow away induction balance metal detectors, and do so at a price people can afford? If so, that company would release it, put everyone else out of business, and rake in the millions. That's "Basic Business Practices" 101.

20 minutes ago, PSPR said:

Detector manufacturers don't want to create the ultimate metal detector.  They want to create a detector that is just good enough to be a little better than the last guy - or the last iteration.  That way they can hold back on any breakthrough technology and release it a little bit at a time to keep detectorists buying the next 'best detector' brought to market.

Sorry, but that's not the way it works.

If any metal detecting company had breakthrough technology, they would release it, put all the other metal detecting companies out of business, then have the whole market to themselves.

Useability and the laws of physics limit depth and recovery speed. Again, both those limitations were reached many years ago. It's like what Steve Herschbach said in his article from about 5 years ago. He said, "There are limits on detector depth imposed by physics, and we are already quite near those limits".

https://www.minelab.com/usa/community/treasure-talk/recovery-speed-target-masking

11 minutes ago, midalake said:

Pretty impressive the Manticore can confirm 3 different targets on the coil sweep. Clearly the Manticore won that test. 

The Manti only did better than the D2 because XP hasn't released the update that fixes that weird ID issue. Well, either that, or the D2's Silencer was set too high.

The audio and TID on the Manti, clearly indicated a nonferrous and ferrous targets. In other words, anyone with good experience hunting in iron infested sites, would have been immediately digging regardless of Target Trace. Although showing that there is 3 targets, is kind of cool.

9 minutes ago, Dug D said:

I'm looking for a simple video hunting in an old park with a Manticore, find something just good enough to dig and then before digging, check with other machine(s)  😊

Exactly!

Now that would be a proper test, as long as the tester knows how to set up the detectors with almost identical settings.
 

Induction balance detectors reached their "laws of physics" limitation a long time ago when multi frequency technology was introduced. Improved raw performance since then, and always will be, "subtle" at best. Output power is government regulated, and you can only go so fast with recovery speed or you'll lose significant depth, get audio clipping, or get poor target ID. There is always a give and take.

With detectors like the D2, Legend, Nox, Manti, etc, you're going to get about the same performance, provided that the same coil size and type is used, and all the settings are the same. Well, certainly close enough that in direct comparisons, no one should be saying, "Oh wow! That detector performs way better than the others". 
 

13 minutes ago, Jeff McClendon said:

The Manticore did very well........so did the Nox 900 on exactly the same test done a couple of hours later and recently posted by Iffy. Both had similar results and similar VDIs. Whether other detectors like the Nox 600, Nox 800 and Legend would have similar results.....you guys that are assuming that are making an assumption with no proof.

 

That test was easy for any flagship detectors, as long as the iron bias isn't set high, and the recovery speed isn't set low.

"History Revisited" has an even more difficult ferrous/nonferrous unmasking test with the Legend, Simplex, and D2, than the test in Iffy's video. Only the Legend passed that test. Actually, he's got a few videos on his channel showing the Legend passing more difficult ferrous/nonferrous tests than Iffy's test. Other You Tubers show similar tests, and the 600 and 800 do just as well. Again, provided that the settings are adjusted accordingly.

Also, I don't normally do videos, but a few months ago, I was prompted to do a video on a dare. Long story short, people were amazed that a particular fringe detector was hitting a few coins that were separated and placed directly under a ferrous rod. Again, like Iffy's test, I wasn't impressed. I said that the Legend and Nox could do it even better. I was told to prove it, so I ended up doing a quick crappy quality video with my cheap cellphone. Anyway, not only did the Legend hit each coin, but it did it better than the other detector...and from the videos I've seen of ferrous/nonferrous unmasking/separation tests, the 600 and 800 would perform just as well.

What would be impressive, is if the Manti and 900 were directly compared to a Legend or original Nox (or a working D2 lol), and seeing the Manti or 900 unmasking and separating significantly better.
 

Regarding Cali's video:

He admits that with the D2, he has hit a slightly deeper nickel on another occasion at that beach.

Yes, the Manti was sounding off better than the D2 on that nickel, but the difference was negligible when the totality of depth is considered. Furthermore, that difference was also well within a "margin of error" if all of the other variables are taken into account.

Even aside from all the other variables and the margin of error, if that nickel was raised ever so slightly, the D2 would have sounded off the same as the Manti. That's the other misleading aspect to these type of depth videos. That is, they don't show how much the target has to be raised for the competitor's detector to hit it. Probably because it would barely have to be raised, and that would show that the depth difference is meaningless.

1 hour ago, Digalicious said:

I didn't find the 900 or Manti in Iffy's gold separation test to be impressive. The 600, 800, or Legend, can do the same as the Manti and 900 on that gold, provided that the iron bias and recovery speed are adjusted accordingly.

To add to that:

What I really don't like about those videos, is that newbies aren't told that many other detectors could ID that gold correctly. Check out the comments for those two videos, and so many say things like, "Wow. The Manticore is really impressive for hitting that gold", and all I think is, "No it's not, because any detector with an adjustable iron bias would ID that gold correctly". Yet no where in the video, nor in a reply to such comments, does Iffy mention what I'm sure he knows.

The iron bias is the single most important control to utilize when trying to unmask nonferrous from ferrous. Yet, I've found that a large percentage of long term detectorists, don't know what iron bias is, let alone how to use it to unmask nonferrous in ferrous trash. Which is why so many are erroneously impressed by the Manti and 900 in that test.

 

I didn't find the 900 or Manti in Iffy's gold separation test to be impressive. The 600, 800, or Legend, can do the same as the Manti and 900 on that gold, provided that the iron bias and recovery speed are adjusted accordingly.

Ok Thanks.

I'm familiar with Iffy, and I'll check it out.

Thanks for that NAGANT.

If you have a link to that video, that would be great. I'm most interested in seeing if the TID and/or audio was also indicating a high conductor.

When I'm hunting for nonferrous targets in ferrous infested sites, if I even get a hint of nonferrous tone amongst all the ferrous, then I do the short wiggle, isolate that nonferrous target and dig away 🙂. 

4 minutes ago, longbow62 said:

You keep saying the same thing over and over on 2 different forums. We get it. You don't think the 2D screen is really that useful. You think audio and numerical I.D. tells you all you need to know. That's fine don't buy a Manticore. Those of us who think the 2D adds value and have posted as such to why we think that will find out for ourselves it's utility.

I'm merely trying to find out the benefits of TT. So far, with the info from others, I have found a benefit of TT.

If you don't have anything of value to add, then why are you even replying? How about we keep emotion out of this topic, and stick to the science and technology?

 

2 minutes ago, NAGANT said:

TT will help when you get those mixed signals that you cant work out.  

I like "TT".  I'll be using that from now on 🙂

Anyway, do you mean a mixed signal like a signal in which the TID is jumping around like, let's say, 72-73-79-81? If that's what you mean, then TT will show a long smudge on the nonferrous line. How is that long smudge showing more info than TID? I would go as far to say that with such a target, TID would be more telling, because with numbers, the ID is more defined, compared to an elongated smudge.

Thank you for the video PSPR.

The video shows exactly what I mentioned in my first post about the 2D (ID Map) being an ID plotter with an automatic and preset decay.

My question isn't really about how the ID map works, but rather, if it has any benefit over TID and/or tones.

So far, I can see 2 disadvantages of the ID map compared to TID. The only advantage I see with it, is the ability to expose iron falsing as I talked about in my previous post.

I now do see a particular scenario in which the ID Map can be beneficial. That scenario would be in identifying ferrous falsing, especially if the iron bias is set very low.

For example, when a detector iron falses, the ID will show the nonferrous number, but the ID Map will show both the ferrous signal and the nonferrous signal. Meaning the ID Map exposes the ferrous falsing, saving you from digging that ferrous target that the regular ID number shows as a nonferrous target.

However, many detectors have a ferrous meter that helps to expose iron falsing. One example of this, is the Legend with its ferrous / nonferrous meter, that shows the amount of both the ferrous and nonferrous material in a left/right bar graph. Some detectors just have a bar meter for the ferrous side, and you look at the regular ID to get the nonferrous number.

46 minutes ago, strick said:

No you are wrong. In disk mode you will not hear a TID for the blanked out areas. Just see the target trace only. 

strick 

Are you saying that if a target is discriminated out, then it still appears on the trace screen? If so, that doesn't mean I'm wrong about the trace being a representation of the TID. It just means you chose for that particular TID to not appear on the TID display. But anyway, if a discriminated out target still appears on the trace screen, then how does that give you more information to choose to either dig or not?