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2 hours ago, kac said:

My AT Pro with latest firmware and 9x12 concentric audio and vdi match right to the fall off (older firmware numbers would drop off but audio was still there). The MK has very reliable numbers when gain is not maxed out. 80-85 is where the machine should be and gain above that your simply pushing the machine. In Gen Mode that the vdi #'s are just raw unfiltered response.

When I say I hunt by audio first I do that to judge the target size and depth. My last large cent the numbers were all over the place and buddy passed over it with his Nox 800 for the same reason. Turned out there was a tiny bit of iron in the same spot. Coin was only 6" down. Out here hunting for size of an object has helped me more so than the numbers.

Arguing that you see good results with your single frequency detector does not change the facts of this question. Yes, single frequency does well under many circumstances. Continue to use it all you want, nobody is saying you should not. It works well in your ground - great. Nobody is challenging you and how you detect, so no need for a defense. However, your observations change nothing about the reality of the multifrequency versus single frequency question. It is what it is, actual scientific facts versus anecdotal opinions. If somebody asks the question, I’m sticking with the science, not opinion, when answering the question.

This discussion says nothing about the Equinox being better than other detectors or not. Equinox is not a perfect implementation of multifrequency, just one implementation, and a first version only with room for improvement. Examples of this and that versus the Equinox still do not change the basic facts that properly implemented multifrequency has the advantage. Single frequency, single domain, has less information to work with, period. Single frequency has been developed to the nth degree over decades, every last drop squeezed from what it is capable of. No new single domain, single frequency machine will ever surprise anyone with what it can do. By comparison multifrequency processing is in its infancy with engineers just now beginning to utilize its full capability via high speed processing power and modern battery technology. The first cell phones were a hard sell versus old rotary land lines also. Believe whatever you wish, but multi frequency / multi domain complex processing is the future of metal detecting, single frequency, simple processing the past when it comes to new detector development.

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Just an example of where multifrequency can still go. Right now you will hear it said that when a detector uses single frequency, all the power is focused on that one frequency, which can give slightly better results on that frequencies preferred target class over multifrequency. This is because multifrequency spreads the power out over the frequency range, with each frequency therefore running slight less than full power. It is the compromise of running all frequencies versus a single frequency. However, with that single frequency you are focused on a single class of targets, and will do less well on the other frequency ranges than the multifrequency unit.

But it does not have to be that way. That is mostly a function of battery power and the desire to keep power use within tolerable ranges. With new high power battery technology, the next step will be multifrequency where each frequency is optimized and running at full power equivalent to what you get running at a single frequency only. I expect we will see this development in the relatively near future.

I want to emphasize again that Equinox is not the be all end all of multifrequency. In fact CTX has better target id resolution and excellent ferrous handling that is arguably better than the Equinox. From my perspective the Equinox is just a crude proof of concept for Multi-IQ, with more benefits still to come. It should be fairly obvious that everything Minelab knows about FBS and has learned so far about Multi-IQ will be going into the next generation CTX model.

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25 minutes ago, Steve Herschbach said:

But it does not have to be that way. That is mostly a function of battery power and the desire to keep power use within tolerable ranges. With new high power battery technology, the next step will be multifrequency where each frequency is optimized and running at full power equivalent to what you get running at a single frequency only. I expect we will see this development in the relatively near future.

Good point, Steve,.  One might logically ask that if this is the case, then why not just pump more power into the ground in the single frequency detector case.   That is because we are talking about more effective power management and multiplexing each of the frequency component transmit signals so that peak power demands can be lowered overall - sort of like a time share arrangment.   The other part of the equation is that there is a practical limit (that has already been reached by today's single frequency detectors) that pumping more power in the ground simply results in diminishing returns because of the noise that is generated.  You are getting no depth benefit at that point, in fact you are making things worse,.  This is especially true in mineralized ground where lowering transmit power is necessary to eliminate noise and ground feedback (some detectors like Nox do this automatically in beach mode, while others, like Deus, enable the user to manually reduce transmit power).  This is part of the reason why single frequency detectors have less of a "power" advantages over MF detectors in mineralized soils.  So it is no just a matter of "going to 11" as far as power is concerned, but increasing the power capability across the frequency "spectrum" as something that can improve MF performance vs. SF.  Most of the gains, however, are best leveraged by taking maximum advantage of processing horsepower through use of more sophisticated signal processing programs that can better identify probable junk targets through the tell tale target signal fingerprints of typical junk items.

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Yes, single frequency is already at the limits of what more power can offer before it is counterproductive. Multifrequency is not, which is why you see that as a sales pitch for single frequency. I do think we are a long way still from what sophisticated signal processing can achieve with multifrequency.

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So, to return to the original question, those who do not detect in areas where there is moderate to high mineralization/saltwater conditions may not see any benefit from one of the current simultaneous multi frequency detectors, i.e. the Equinox on shallow to medium depth targets like the example kac gave concerning a 6" large cent co-located with iron. That makes sense to me. However, whenever anyone tells me I just don't know what my single frequency detector is really telling me, I just want to throw up. I wish I had soil conditions like that to hunt in.  In my soil conditions that dividing line between a single frequency detector running at high transmit gain versus the Equinox is 3 to 4". Past that depth, absolutely any single frequency detector has zero reliability as far as multiple tone ID or numerical target ID accuracy. Every target past that depth becomes an extremely high conductor or an iron target so the entire low to mid conductor target accuracy is completely gone. So, a single tone beep and dig detector with good ground balance capabilities,  no display,  an 11" DD or so coil and ample transmit/receive power running above 14kHz would do just as well. 

So, I have two choices,  use and learn my single frequency detector's minute nuances and interrogate the target for several seconds (or more) along with do some mental math (do I add or subtract 20 to 40 target ID numbers to what I think the target is and take a chance????). Or, do I use a more appropriate simultaneous multi frequency detector for my soil conditions, spend less time analyzing targets and dig many more quality targets which are accurately identified with appropriate tones and numbers down to at least 11" or more?

I took my G2+ yesterday for a short hunt in an aluminum trash filled local park. I am not a big fan of the discrimination mode on the G2+ because of its tone choices. Basically it is a 2 tone detector in discrimination mode depending on if and where I set the V-Break and iron volume. I basically just wanted to cherry pick copper pennies, dimes and quarters so I set the tone break between low tone and VCO tone pretty high (80), just above zinc pennies and only dug VCO tone targets. I dug so many zinc pennies, 4" deep pull tabs and a couple of US nickels that it was extremely frustrating. I dug plenty of dimes and quarters too but that up averaging is just not fun. I still love the Tek G2+/F19/Time Ranger Pro form factor and since this Tek G2+ was my first really good detector with a display after many years with a Lobo Super Traq, I will never sell it. To be totally truthful, the Garrett AT Gold was my first VLF with a screen but it went bye bye really fast....... (couldn't stand the unadjustable iron audio). The Tek G2+ pistol grip and threshold based all metal mode are just too good. 

But, I am so thankful that the Equinox with all of its great features and obvious faults, came along and revitalized my desire to keep dirt fishing for coins and jewelry after too many years of target ID accuracy misinformation and frustration. I also look forward to using the Garrett Ace Multi-Flex Apex!!!!

 

Jeff

 

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In my mild soils the Gold Bug Pro/F19 and the rest of the alphabet they use for other model numbers of the same detector is very good for target ID's until the targets get very deep then the Multi frequency detectors shine. With the Multi Frequency Equinox and Vanquish they will lock on to an exact number say 21 for a $1 coin, where as the GBP will bounce between 77/78/79/80/81/82  for a $1 coin, how much of this is due to it having 99 ID's instead of 50 I don't know as it's pretty easy to slip a number or two with double the range but it is pretty good with ID's.   Once the targets get very deep the GBP starts to expand it's range down into the 60's and up to the 80's for that same target where as the Nox and  Vanquish will sit still on 20/21/22 for the target.  I assume this is to do with multi frequency providing better target ID's at depth.  I am very much looking forward to the Multi-IQ v2 detector, I would guess it's been in development since they released the Equinox.....  I still can't help but think they did something slightly different with the Multi-IQ in the Vanquish than they did with the Equinox, I am hoping whatever it was they'll put into an Equinox firmware as for some reason the Vanquish seems to handle EMI better for me and something is special about Jewellery mode.

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A very good question,i personally use a selection of both 'fixed' single freq machines and multiple freq as well and also 'selectable' individual freq machines.

Multi frequency machines have some massive advantages like the ability to be used in salt water environments like beach detecting etc and also for high mineral ground conditions,so that is one area that i use such a machine as the Equinox,but i also use the selectable freq Deus and if i am honest that is my preferred option as that covers with the coil options all my main everyday needs.The main reason i use the Deus over say the Equinox is the slightly better coil choice,the HF elliptical i find works exceptionally well  on my roman/saxon sites.

Then i also use specific 'single' frequency' machine for site specific use,these are machines like the Nexus MP that i use,single freq at a time,and can be changed like the Xterra by changing the coils over to a more suitable freq for the job in hand,the main reason i use these specific single freq machines is that they have the ability to use higher power into the coils like the Nautilus detectors can but more so in the case of the Nexus MP i think i am right in saying the voltage is upto just over 100 volts,this is what makes it special and the main reason i use it as do others for its ability when coupled with a larger coil/s to go into the depth range of say a Pulse machine but with discrimination which a PI machine in theory does not have or certainly not in the same league.Of course this type of machine is not your every day use machine and more specific use,but it does show just how in some situations that a single freq VLF machine can excel as it has no competition in theory.

So yes i do use a selection of both single freq and also multiple freq as i take advantage of specific coil options that some machines offer over others,no single freq or multiple freq detector/coil combination does it all,this is why personally i have a wide selection of detectors and coils,so i can mix and match in what i consider the best combination for that days detecting scenario and the ground conditions.

Todays multi freq detectors with say a 11'' DD are designed as a happy all round medium combination and for most cases should be all you really need,but also in some specific cases a single freq machine can excel and increase the odds in your favour.

 

 

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7 hours ago, Dances With Doves said:

Hello   Phrunt.Do you ever use a  recovery speed of 4 on nox?

I have tried various recovery speeds, I honestly didn't notice any difference going lower other than the audio changed, I didn't find any difference in finds so I just went back to defaults.  I know technically slow recovery speeds should be deeper and fast better in trash, I don't have to worry so much about the trash in most of my spots and the depth didn't really seem to make a difference when I went lower.   I tried lowering on deep targets to see if they improved at all no difference. Maybe more beneficial in worse soils I guess or I've just not found a target that's at the exact right depth for it to make a difference who knows.  I'll keep experimenting though, I like experimenting 🙂   I can see faster recovery speeds being beneficial in trashy areas so I'll play more with that.  Same with the Vanquish, I found no benefit using Relic mode (deepest mode) to find deeper targets, Jewellery mode did the trick just fine.

It seems like a lot of things metal detecting, what works in one location doesn't in another so people always have to work out what works best for their locations.

At the moment I'm comparing single frequencies in performance to multi frequency, by finding the targets in multi then checking them in each single frequency.  I'm finding so far Multi is giving better ID's.

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5 minutes ago, phrunt said:

I have tried various recovery speeds, I honestly didn't notice any difference going lower other than the audio changed, I didn't find any difference in finds so I just went back to defaults.  I know technically slow recovery speeds should be deeper and fast better in trash, I don't have to worry so much about the trash in most of my spots and the depth didn't really seem to make a difference when I went lower.   I tried lowering on deep targets to see if they improved at all no difference. Maybe more beneficial in worse soils I guess or I've just not found a target that's at the exact right depth for it to make a difference who knows.  I'll keep experimenting though, I like experimenting 🙂   I can see faster recovery speeds being beneficial in trashy areas so I'll play more with that.  Same with the Vanquish, I found no benefit using Relic mode (deepest mode) to find deeper targets, Jewellery mode did the trick just fine.

It seems like a lot of things metal detecting, what works in one location doesn't in another so people always have to work out what works best for their locations.

If the vanquish is doing better then the nox you   can't argue with results. If it handles Emi  better then nox then that could make a big difference on targets   . The coils could    also be  better then nox for emi.  I Would like to see you with the apex in your coin fields.If I was in charge of Garrett I would send you one.

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      1999 Minelab Golden Hawk        6.4 kHz    20 kHz    60 kHz
      2002 Minelab Eureka Gold        6.4 kHz    20 kHz    60 kHz
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      2006 Minelab X-TERRA 70            3 kHz    7.5 kHz    18.75 kHz
      2009 Minelab X-TERRA 305            7.5 kHz    18.75 kHz
      2009 Minelab X-TERRA 505        3 kHz    7.5 kHz    18.75 kHz
      2009 Minelab X-TERRA 705        3 kHz    7.5 kHz    18.75 kHz
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      2017 Nokta Impact            5 kHz    14 kHz    20 kHz
      2017 Makro Multi Kruzer            5 kHz    14 kHz    19 kHz
      2018 Nokta Anfibio            5 kHz    14 kHz    20 kHz
       
      Multiple frequency or multi frequency machines have become very confusing, as a lot of marketing material has focused on the number of frequencies transmitted. What really matters is what frequencies a detector receives, and how the information is compared and processed for results. Some commentary here. Many people look at the marketing material and assume that a machine processing multiple frequencies is somehow working across the board to deliver the best possible results at all frequencies. However, the two issues outlined above do apply. The machines are employing harmonic frequencies, and so cannot compete with a machine optimized at a single frequency as opposed to one of the distant harmonics running at less amplitude. Second, making one coil run perfectly at all frequencies is extremely difficult, again giving the dedicated machine an edge.
      I highly recommend people not go down the technical rabbit hole but instead focus on what the machines do, on how they act. Two things are very apparent.
      First, the big market for a long time was coin detectors, and the goal always was to identify coins as deep as possible while ignoring trash as well as possible. Processing two or more frequencies simultaneously gives the detector engineer more information to work with. All the focus was on developing great coin detectors and guess what, the multi frequency machines for all intents and purposes act just like very good lower frequency coin detecting machines. Good ground rejection, and great discrimination on coins for as deep as it can be achieved. The multi frequency machines don't really go deeper than single frequency coin detectors, they just do a better job delivering clean discrimination results to depth.
      Here is a list of introductory models of multi frequency detectors and year of introduction. I am not listing all the derivative models to reduce clutter. I will post that later. 
      1991 Fisher CZ-6            5 & 15 kHz
      1991 Minelab Sovereign            BBS
      1999 Minelab Explorer S/XS        FBS
      2001 White's DFX            3 kHz & 15 kHz (Simulates single frequency by ignoring half the dual frequency signal)
      2012 Minelab CTX 3030            FBS2
      2020 Minelab Vanquish             Multi-IQ
      Second, single frequency detectors have a ground balance problem. They can ground balance to mineralized soil, OR they can ground balance to salt water. Multi frequency machines can reduce signals from both mineralized beaches and salt water simultaneously, making them ideal for saltwater use.
      1993 Minelab Excalibur   BBS (Sovereign in waterproof housing)
      1995 Fisher CZ-20             5 & 15 kHz (CZ-6 in waterproof housing)
      2001 White's Beach Hunter ID   3 & 15 kHz (DFX in waterproof housing)
       
      There is a third class of machine that can run either as selectable frequency OR multi frequency detectors. Quite rare at this time. 
      2009 White's Spectra Vision   2.5 Khz or 7.5 kHz or 22.5 kHz or all three at once
      2018 Minelab Equinox   5 kHz or 10 kHz or 15 kHz or 20 kHz or 40 kHz plus multi frequency options
      2020 Garrett Ace Apex   5 kHz or 10 kHz or 15 kHz or 20 kHz plus multi frequency options
      In my opinion multi frequency has delivered well on its promise. The Minelab BBS and FBS machines are renowned for their ability to discriminate trash and detect coins due to their sophisticated processing. Again, focus on what they do. Not even Minelab in their marketing tells anyone these are prospecting detectors. Second, the Fisher CZ-20/21 and various Minelab Excalibur models are without a doubt the most popular and successful non-PI saltwater beach detectors made.
      I have a White's DFX and I think it is a fantastic jewelry machine in particular. A good coin machine but lacks a bit of punch. The Vision/V3i upped the ante but while amazing on paper suffers from interface overload. The Minelab units are simple by comparison and a lesson on how people in general just want the detector to get the job done. Feature overload is not a plus. However, I think White's has the right idea. The ability to run either separate frequencies or multiple frequencies at once is very compelling. I just think nobody has really done it right yet in a properly configured package. The V3i has the ingredients, but needs to be stuffed in something like an MX Sport with a simplified interface and improved ground balance system. (2018 note - Minelab Equinox released). It really never did beat the White's MXT in some ways and many people when "upgrading" to the V3i end up going back to the MXT.
      Selectable frequency has yet to really deliver on its promise in my opinion. So far it has been difficult to produce a selectable frequency machine that truly performs at all frequencies on par with a dedicated single frequency machine. The Minelab Eureka Gold at 60 kHz just never gets mentioned in the same breath as the White's Goldmasters/GMT or Fisher Gold Bug 2. Also, most selectable frequency machines in the past have been very feature limited prospecting machines, restricting their overall market appeal. 
      I personally think we have seen enough variations of single frequency detectors. I do not believe much can be done to exceed the performance of the dedicated single frequency VLF type machines we currently have. What can obviously be done is a better job of packaging machines that deliver true punch at different frequencies, or multi frequency machines that bring across the board performance closer to what is expected of PI detectors. I do think we are seeing this happen now. The new Nokta Impact and the new DEUS V4 update are expanding the available options in selectable frequency in more usable packages. The Minelab GPZ and other hybrid platforms blur the line between what is traditionally considered PI and VLF and simply need the addition of discrimination to go to the next level. There is still a lot of potential to deliver machines that might reduce the number of machines many of us feel compelled to own by delivering more across the board performance in a single machine that would now take several detectors. Exciting days ahead.
      For those who want to try and get their head around selectable frequency and multi frequency technology, Minelab and White's have a gold mine of information in a few of their references. Dig into the following for some great explanations and diagrams.
      Minelab - Metal Detector Basics and Theory
      Minelab - Understanding Your X-Terra
      White's - Spectra V3i Owners Guide
      White's - V3i Advanced Users Guide
      Better yet are the last three parts of the DFX instructional video by White's featuring engineer Mark Rowan explaining frequency and multi frequency methods:
       
       
       
       
    • By Abe2020
      Is this detector able to detect diamond? I am trying to find a diamond from a ring that fell out a number of years ago in my  garden. My friend Aberal Molzesman said in his blog tha it is possible.
    • By Steve Herschbach
      Steve's Law of Target Depletion - All good locations with high value targets will be detected with progressively more aggressive means until no metal can be found. When any location contains items of great perceived value, detector technology will normally be applied in reverse order of aggressiveness. First will be VLF discrimination "cherry picking". This will be followed by varying degrees of "turning down the discrimination" to dig iffy targets and then on to using the barest of ferrous/non-ferrous discrimination. This will finally be followed by "all metal" detecting to remove masking effects with either VLF or PI detectors. If the location is considered good enough all targets will eventually over time be completely removed until no detector is able to acquire a target. At this point a site may be considered "hunted out" until a new technology arrives allowing for more depth or ground separation capability, when a few more remaining metal items will be removed. The key concept is that since discrimination is unreliable, all metal items must be removed from high value locations in order to rest assured nothing has been overlooked.

      Nugget hunters and beach hunters get right with the program. If a nugget "patch" is located it will be relentlessly pounded until no metal remains. Beaches survive to some degree by being a renewable resource but even on beaches the richer, older deposits of jewelry are worked out over time. Good relic locations can and will be subjected to the same attention given to nugget patches, detected relentlessly until no metal remains. The rule is that as long as you can find a piece of metal hope remains that good items can be found. If not you, somebody else can and will return until no metal remains. I have promoted PI detectors for all uses for this very reason for over 15 years now - see that last few paragraphs at www.losttreasure.com from 2005.
      Most people consider depth to be problem number one, but for many areas target masking is by far the more serious issue. Until detectors can actually see through trash instead of blocking it out, even the smallest surface trash can and will block deeper adjacent items from being detected. Superb discrimination only gets you so far and ultimately the only solution is to remove the surface trash to see what lurks below. The only real limitation we face in this regard is in areas sensitive to digging holes of any sort, like a well groomed park. Even there, slow careful extraction of surface trash over time can reveal old coins missed by others for decades.
      Beneath The Mask by Thomas Dankowski
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