12x10 SEF Coil Field Tests & Trials. Is She A Keeper?

[Critterhunter]

It is drastic! After thinking about it over night, I was hoping some better words would come to mind to help people understand how it sounds. It's interesting that you would note similarities to the Etrac, because after a little thought I'd say it's more similar to my Explorers in certain ways. Not as short and "untelling". It's still nice long audio compared to most detectors, but it sure does feel and sound shorter, crisper, or faster for a Sovereign. The 10" and 15x12 coils were not that much different in audio. Just that the 15x12 tended to have a slightly more smooth basey sound to it, helping to draw out the subtle distinctions in targets a little more than the stock coil, which is an excellent coil. Not knocking it. Way better than any 10" coil I've used on my Explorers.

With a night's sleep on it and Sunday's short one hour hunt (details below), I can perhaps describe it a little more specifically. The whole ball of wax relates around how this coil reacts over targets. When I said "jumpy" before that wasn't a good description. I don't want you to think this coil is more unstable (it's not, see below) or something touchy in how it works. A better descriptor would be this...It takes far less motion of the coil in the left/right perspective to approach, cross over, and leave the edge of a target. Seemingly with the flick of your wrist you have now passed over that target in complete fashion. The wiggle still works like it should, drawing out the best ID from a target. It's just that when you are doing your normal lazy sweep over a target you just found you'll instantly see that things are much more well defined, and it takes far less effort to approach, cross, and leave the target with the tighter left/right DD detection field of this thing. It reacts "fast", and recovers "faster", than the 10" or 15x12 coils. It's no exaggeration, the width of the DD dection field feels tighter than even the S-5 coil. That's what really blows my mind.

I would guess that this is the reason why the audio sounds so different. Somehow the tighter field is making the audio raise in pitch a bit, or at least sounds to have much more treble in it and less base. Now, I can see how this coil would be able to separate targets better over the other coils without having to wiggle on each one or slow your sweep speed down to a super crawl. When I was sweeping over the tabs and iron in a patch of ground in close proximity to each other I realized that. I could do my usual "searching for next target" sweep speed, which is a faster than most Sovereign owners use, and see distinction and separation in the targets without having to slow down or wiggle over all of them to figure things out. As I said, if I didn't know any better and you handed me a mysterious Sovereign with this coil on it I would have bet money that somebody turned up the processing speed or somehow adjusted the recovery speed in some way, such as an adjustable SAT speed (self adjusting threshold). The audio pitch of everything is a bit higher. Nickles sound a little higher, like the low end of the pull tab range somewhere in the 150 to 152 VDI number range, where as the meter is reading like it should. In this particular case 146 or so. Silver now sounds like my QXT Pro, which I had become accustomed to in training my ears to hear that slightly higher audio pitch than the GT using the stock coil gives. That's not really a pro or con for most people, as a properly trained ear will soon learn the pitch range of targets on the GT. I've just logged so many hours with my QXT Pro and found so much silver with it that it's a hard habit to break to not listen for quite as high a pitch for coins that I was used to on the QXT.

The closest probably most accurate description of the audio change is that it's just like the treble has been cranked up on a radio, but it is also faster in it's reaction (detection and recovery) of targets too. It literally feels like the field is a very thin line projecting directly into the ground. That's not a drawback, as coverage does not suffer. So long as you sweep the middle of the coil over a target like you should on any typical DD or concentric coil, it's going to get heard. On the other hand, there are very real benefits to a tighter field. Easier separation without having to get as intensely "busy" wiggling and working or crawling the coil between targets. Translation- It'll be easier to notice two targets near each other when swinging faster than you probably should in normal "search mode" for your next target. That standard speed of sweeping can be a little higher and yet you are going to see things easier. The hit, sound off, and recovery of the threshold IS faster. I'm not equating that to somehow the processor being sped up, but darn if it doesn't feel like that!

The real perk, besides all the above, is that in theory the coil has less ground matrix bleeding in from the sides, and so perhaps that means a bigger coil really can go deeper in your high mineral ground where as you may have found an 8 or 10" coil was the max limit you could go to for best depth. Not just perhaps in being able to see deeper without losing the target in the ground matrix, but also in it's ability to run at higher sensitivity levels without getting bumped around by minerals, iron, hot rocks, or other little "no-see-ums" in the soil that would otherwise cause the machine to be too unstable at higher sensitivity levels. I'm not a fan of maxing out sensitivity since in my soil it doesn't appear to provide max depth, but for those in that camp it's a very real potential. On the other hand, I may have changed my theory on this strategy. Not for my 10" and 15x12 coils, but read below and you'll see how the 12x10 seems to differ in that respect, at least at one of my sites.

Crazyman, I sure do plan to run this coil at that one bad beach and see if it gets deeper, allows higher than ultra low sensitivity coils that my 10" coil needed, as well as how target quality is or isn't improved. The 10" coil really had problems at that site. Must have been the perfect storm in terms of sand matrix and minerals that somehow had the 10" coil's number, because I've never seen that coil react like that. With the 15x12 doing much better there I have high hopes that the 12x10 will follow suit. My real interest is in this coil's potential depth. All the other issues discussed above are a side benefit in my mind. Sure, nice to have those features but I'm trying to beat the depth on land (not sand) of my 10" Tornado's already impressive performance. I've never dug coins on land as deep on any machine using any coil, but that doesn't stop me from trying to improve on perfection.

The stability of this coil at high sensitivity levels as well as it's sensitivity to tiny targets will be discussed in the next message (probably in an hour or so here). I have some very interesting findings on both those things and a few other aspects after a short one hour hunt I took yesterday.

 

[Critterhunter]

Here's how I'd equate the feel of this field and the resulting differences in audio and reaction...

Let's say you take a knife and use the back of the blade (the non-sharp side) to try to cut into a tomato. Things get crushed, squash, and squirm out from the sides. Now imagine flipping that knife over to the correct side and doing the same thing. It's very precise and surgical. In that respect even though the machine's processing ability isn't really being sped off, it rises, goes acrossed, and subsides over the target much faster. It takes a bit of that "lag time" out of a bigger field that takes longer to ride up and over a target, and in that way the machine's recovery or reaction speed is enhanced in a very real way. You WILL think the machine is running faster.

OK, onto yesterday's one hour hunt. I wasn't really into hunting and had things to do that day, but I wanted to get the ring I found over to a friend's to have the picture taken. For that reason I took along my machine and stopped at a spot I like to hunt that's near his house. Now I could see just how high sensitivity would go on this coil without getting instable, as well as judge a few other things about it like it's depth ability. That's the most important key factor in my trials, as all the other benefits are icing on the cake to me. All great, but I want to push my GT a little deeper at some of my pounded out sites than the stock 10 coil's already amazing depth ability has. As said a billion times before, the 15x12 seemed to max out in depth in my soil on land at perhaps 8 or 9" on coins. Maybe a little deeper, but in the sand the 15x12 took the lead for me. Where as the stock 10" coil would get excellent depth, the 15x12 would surpass it by 2 or 3" on coins on my beaches. Even the ones that didn't seem to give the 10" coil issues. Both coils got deeper in the sand than on land, but the 15x12 really went DEEP.

So I fire the GT up and start playing around with sensitivity before I stick a dime in the ground to calibrate it that way. Tried 2PM, as is the norm for the 10" and 15x12 coils at many of my sites. Sweep around several minutes to get the feel for it's stability. Fine and dandy as far as that goes. Time to raise it up more. Noon found me saying the same thing. OK, let's go to 10PM, as I would think 11PM would be pushing the limits for most of my coils in most of my sites if I wanted to max sensitivity out to the very edge. Still running smooth as silk after 4 or 5 minutes of traveling around and sweeping, as some times too high of sensitivity doesn't show until you get into a rougher patch of ground. Hmmm.....OK, let's push it right to the limits.

Full blast manual. No way it's going to handle this, I thought, because even though the 15x12 can often go higher in sensitivity than my 10" Tornado coil, rarely would it let me ride to the very max of sensitivity and still keep stable. Oh sure, at several sites it would do that, where as the 10" coil might not be able to handle say anything higher than 1PM or maybe 11PM in a particular area. WOW! The GT is NOT nulling out due to ground matrix overload or anything! Don't believe it. Keep hunting around in various areas waiting for the threshold to start nulling or getting eratic. Stable as anything! Not a hint of riding the edge! Oh sure, I'd get the occasional null like every 10 sweeps or so, but on further investigation that was do to iron being present in that spot. If you ever can't decide if a null is iron or too high of sensitivity, try sweeping over the same spot again and again. Overloaded sensitivity will randomly come and go, being a null some times and not others when traveling the coil over the same spot. A null caused by iron will always be there, never move, and never vanishing every other sweep.

Although I've been able to run the 15x12 full blast at some spots, never at this one. From memory about 11PM on the dial was max for it, maybe a little higher, but for sure not full blast like this. Just like the 15x12 was more stable at higher settings than the stock coil, it looks as if the 12x10 is even more stable than the 15x12! I'm sure at other sites it won't allow full blast, but that's not really the point. It shows potential owners of this coil that have soil that permits riding the edge of stability to provide best depth in their soil. I'm confident you can crank this puppy much higher than the stock coil and really push your depth limits. For me, on the other hand, at least in my soil I prefer sticking a dime in the ground and calibrating it that way, as riding the edge often doesn't provide best depth/target quality. Still, that may change for this coil. Read on...

So now that I know this thing can run full blast at this particular site without the hint of instability (and I MEAN that!), let's see how the old dime test ends up wanting sensitivity to be calibrated. At about 7.5" deep in the ground (I use my digger to measure) I stick a silver dime. Pack the soil back in as hard as possible as I go and put the plug back in place, stepping hard on it to make sure the ground matrix is as close to being undisturbed as possible. Throw it in Auto. No response. Hmmmm....sometimes Auto gets coins at that deep for me, but not here on this day. Throw it over to 3PM. GT could hit on the coin, but not well enough to get all the way to 180 with the wiggle. Raise it up to 2PM and now it's hitting and IDing fine. Interesting to note where Auto had it set this particular day, because often I'll find Auto to be about 3PM to perhaps two, and well able to hit a coin that deep.

OK, let's get a little more intense here and see just how high I can go without destroying the target ID, audio, or having the target null out on me (possible to do in my soil with too high of sensitivity, even if the machine is rock solid stable). Noon seems to show just as stable of target ID, without it breaking away and me needing to pull it back to 180 like too high can do to targets. More "Hmmmm...." thoughts going through my head. Usually the 10" or 15x12 at most of my sites wants a 2PM setting. Sometimes lower and sometimes higher, but often getting up to noon or higher makes the 180 ID harder to lock and hold, being more erratic. Alright then, let's head into no man's land with this 12x10 and see just how high I can go without target ID or audio instability. Note that this is often still well below what the very edge of stability is that most people like to ride. The machine might be stable, but the target ID is harder to get your hands on and say "Stay right here for me".

9PM and all is still well!. Let's stop playing games here....All the way to full blast sensitivity. Easy target ID, holding 180, no nulling, but a little harder to hang onto than say 11PM. 9PM started to hint at that fact, but I wanted to be sure. Just the same, I would have never guessed that full blast peddle to the metal sensitivity would allow the GT to still grab and hold onto a proper target signal without it wanting to wander off on me. Never seen that with any of my coils. Sure, they can sometimes do that at full blast, but they are always trying to bounce around if say you let it sit for a second or two while you think about things.

Well, I travel up and down the dial two or three more times, as I'm prone to double and double re-check my calibration. It's important not to wander off on the target when doing this. Keep your feet in the same spot and don't move, because often a target at depth will give a bad signal one way and a much better one the other. Odd trait, so I'd practice this method if not for anything other to see the pattern and response deep coins give, along with how they can totally go bad on you when swept in a 90 degree change in direction over the target.

Once again everything jives. I should have stuck the coin deeper to narrow down the setting or at least make it more obvious as to what setting it wanted, but I could discern a slightly harder to hold ID on the target at somewhere between 11 and 9PM n the dial. Oh, I could be very happy with how easy it was at full blast, but I like my ID as effortless as possible. 11PM it was then, just to play it safe. I've found slightly too low of a sensitivity setting is almost impossible to judge a depth loss compared to something slightly higher, while I've also found that slightly too high can have more ill effects (unstable ID, nulling, what have you). For that reason I always tend to leave my margin for error on the low side. It'll not suffer in depth and the added perks (less tricks by iron coin spikes, as smooth as it gets operation, much more friendly ID that will sit still for you, etc) will more than make up for it. I defy you to see any difference in depth from say 2PM on the dial versus noon, or say 9PM and 11PM. I've never seen it, and I'm talking testing on fringe stuff here. Sure, it's going to happen when that number range gets wider, but more often that not too high will do less for me in my soil.

Alright, now I'm questioning my results. I leave it at 11PM and wander around, waiting for the machine to say sensitivity was too high. If that was the case then I'd drop it to noon or even down to 2PM. However, I've almost never found a time when the buried dime test ends up with the best/easiest ID being something unstable. It's always well below the edge of that. Still, I'm a suspicious type of person, so I raise it all the way to full blast and wander around again, wanting to prove to myself that the first stable stance of this coil was a fluke. Nope, still smooth as glass. Alright, wander back to the buried dime. Once again check various settings. I would have been quite happy with it ending up at my more often than not 2PM setting of my other coils, but I can't remember the last time full blast or even 11PM was the best setting for ID and audio at depth!

That tells me a few things- This coil is more stable, at least thus far at this site. People with lower minerals who like to ride the edge of stability for best depth should find that they are able to go higher with this coil, thus increasing depth. Still, people like me who have higher minerals will find that my buried dime test ends up being much higher in sensitivity. In fact, as said it was good enough at full blast to run that way had I wanted to. Yet, I like to error on the side of caution for the above already discussed too high/slightly lower perks and cons.

After all that jazz I only had enough time to hunt around for maybe a half hour. Nothing spectacular, just a few copper (non-wheat pennies and a quarter). One of the pennies gave the exact same good/bad signal that the silver ring did. At 4 or 5" it was on edge like the ring. Speaks more to the reputation of these coils revealing coins on edge that aren't even all that deep yet Pro Coils and other "conventional" designs can't see for some reason. While this response wasn't text book both ways, it was perfect one, and you might expect lessor coils to not be able to even muster that. The response they give might be well below your standards on what is dig worthy.

Did manage a gold pendant in the shape of a flag that read like a penny. Don't believe it's gold having read that high, but I'll still check it out. Depth potential is still something up in the air yet. I need to test it against my 10" coin on some deep coins. What I can say is that I did dig some tiny little bits of aluminum that this coil banged the hardest on I've ever heard with any of my coils. I'm talking several times a flake of aluminum about the size of your pinkie finger nail. If you've got real man hands then compare it to your girlfriend's. My only word of concern is that a few of these gave me rather good/stable ID and audio, where as I don't notice that as much with the 15x12 or 10" coil. Way too early to tell if that's a problem, or if I simply haven't learned the subtle telling traits of trash that is not uniform in shape on this coil yet. Might have just been due to me running sensitivity even higher than I every normally would with my other coils. We all know that cranking it real high can start to lose target traits or make iron spikes look more like coins. More time to play with that before I can say pro or con.

Hope this helped so far. Depth and further issues will be dealt with in the days to come.

PS- The weight issue is a non-issue. This coil without it's cover feels much lighter than the 10" Tornado. I got my scale back so I'll weigh it and post some weights with and without cover. The added size dimensions of this coil for sure gives me the feel of more coverage over the stock coil, which I can't stand using on land now that I've got used to my 15x12. Just feels too small like a sniper coil, and I'm constantly worried I'm missing stuff. Not so with the 12x10 like the 15x12, and that added coverage has got my walking/sweeping speed back in tune again like it was with the 15x12 without always having to think about what the coil hasn't covered yet before I take my next step.

A final detection field note- I'd also compare the faster response of this coil to driving in a big Lincoln town car versus a more nimble Mustang GT. It's reaction time is much faster, and without as much swing effort to clear targets. Don't let this fool you. It's still hot and like a mini-concentric near the middle, with bigger girth in that area than your average DD to increase the chances of bumping into the sides of targets you otherwise would have just missed, but at the outer front and tail portions of this coil watch your feet or you might get a nasty razor cut by the signal! Use the front or back ends to further investigate multiple targets or pin point. Works like a dream for these SEF coils. I often "stick the tip" in there to sort out targets I'm looking at. If PP in PP mode sounds off to multiple targets or drags your coil to the side then just PP in discrimination with the tip or tail. It's an awesome way to dig a coin and not have to dig 3 or 4 other bigger junk targets first.

 

[Critterhunter]

I too would like to hear from somebody who has compared this coil's audio to their 10" Tornado or 15x12 coil. It may be that I've got a funky one of some sort, but I highly doubt that. All seems normal, just different. I've even contemplated that perhaps my headphones have changed in some way, but I also doubt that as well. Regardless, there is no doubt that the coil field detection of this coil is very different, very tight. In fact, I was just thinking about how I could relate these traits to you guys in a more distinct manner, as for once I seem to be at a loss for words, or at least as many words as I usually use. Then I remembered the old saying- That a picture is worth a thousand words. Or, in my case, a picture is worth about ten thousand of my words. So I decided to draw up a picture of a conventional DD, the 15x12, and the 12x10 in the hopes to better illistrate this to you...

 

[Critterhunter]

So what's the pros and cons to the above picture of coil dynamics. Well, not only do the SEF coils have less bleed off into surrounding air space than average DD designs, but they are hotter in the center. What this means is tighter separation and improved target outlines and shapes. Even with the fatter concentric portion in the center of these coils, you'll notice even better separation than typical DDs dead center without having to resort to using the tip or tail DD portion of the SEF to outline or separate targets. How can this be?

Look closely at the picture. There is much more "stray" or fuzzy signal at the edges of both the DD and concentric portions of the SEF coils than there is of the typical DD. What that means is when a target crosses that line (into the DD or concentric portion of the SEF), the edge of that line it's crossing is tighter and sharper in resolution. Results? Easier to outline and separate targets, even using the concentric center, where as the fuzzy/foggy edges of a standard DD radiate out into space more. The target starts sounding off further out and in a much less defined way, where as with the SEF it has more of a "line" to cross that you can investigate targets with. Jagged edges of junk will reveal themselves easier, as it's being looked at more with a well defined edge of the DD or concentric signal.

For that reason even the concentric portion, while hot and "reaching out" to the sides for targets that you might otherwise just miss, isn't doing this further than it should or in a less focused way. The image is sharper, more crisp, and it's easier to define it's shape in a much more distinct way. Improved separation is only one benefit to this, target distinction and outline is another.

So you've got the best of both worlds there. Hotter concentric center than a regular DD, yet with more separation and target identification. The trade off in going from a DD to a concentric (broad/clumsy signal) has in a sense been morphed into the wider detection field of a concentric yet with target defining and separation abilities of a DD. Further, investigate a target with the outer portion (say last 4 or 5 inches of the tip or tail of the coil) of the coil and you've now got a surgical knife that's even tighter and more well defined than the tightest of DD designs. See, targets, investigate them, separate them, pin point them...All with much more ability than any coil you could ever dream of.

The other benefit is that that tighter more well defined field as well as less stray signal at the edges (which has no real benefit anyway, you should always sweep over a target with the center of any coil) doesn't muddy up a target's response. More importantly, again in theory here, is that the coil is soaking up less ground "fog" or matrix into the detector's processor. Results are less target degradation, and probably the ability of a bigger coil to see deeper in mineralized ground where as you've found a conventional DD of similar size to be past the point of no return in terms of getting deeper. IE: A regular coil is seeing too much ground with the target, and losing it in the matrix of what else is being "bled" into the signal by the less distinct field dynamics.

As said, the best of both worlds- The equal in depth uniformity of a DD coil from tip to tail, where as concentrics are only deepest at the very center (roughly the size of a quarter at it's very deepest tip). The better separation and less ground matrix of a DD over a concentric, improved even more so with a much more well defined "edge" to it's field. And yet with the hotter center of a concentric that wants to reach out and suck in targets that might otherwise just be a little too off to the side for a standard DD design to notice (at least distinctly).

As much as the 15x12 is an improvement over typical DD designs of say 10" coils, the even more pronounced and tighter "more responsive" and "target defining" field of the 12x10 will knock your socks off! Either coil is an awesome improvement in several respects of standard DD coils. Just make sure the 15x12 isn't past the point of no return in terms of providing you more depth than the standard 10" coil on targets. In high mineral land sites it was for me, though a vast improvement in every other respect over the stock coil, and it's depth did show it's self to me on the beach. Lean towards one or the other depending on your soil content. Less minerals, consider the 15x12. More minerals, lean towards the 12x10. As said, even if you found the 10" or say a 12" coil to not provide better depth in your ground, there is a very real chance that the 12x10 will due to it's shutting out of extra ground content that other coils can't help but be forced to stew in.

Well, I guess a picture was only worth killing about half of those ten thousand words I had in mind. This is the best way I can describe it, and that picture is the best way I can show you how things feel to me. Not saying I'm 100% right on all these theories or even the picture of the coil field dynamics. I can only go by what it feels like to me, and as we all know that sort of thing can be highly subjective when no real way is available to actually see the fields being generated. Hope this helps. I need a smoke now.

 

[Critterhunter]

Man, I have a habit of saying (typing) the exact opposite of what I'm trying to say...

Look closely at the picture. There is much more "stray" or fuzzy signal at the edges of both the DD and concentric portions of the SEF coils than there is of the typical DD.

Mean there is much LESS stray or fuzzy signal at the edges of both the DD and concentric portions of the SEF coils than that of a typical DD (or concentric for that matter). Here's one last quick analogy to try to make things more clear. I'll try to be short, I promise...

Those little squiggly lines you see in the picture is that bleed off or fuzzy stray signals that radiate out from the true DD portion of the coil. They aren't much help at anything, distorting signals, sucking in unneeded junk and ground matrix, making targets less distinct. While better than concentrics at this sort of stuff, a SEF is even further improvement over a typical DD design.

Here's that other analogy I was talking about...Imagine taking a branch off a tree with a lot of little outer tiny branches near the tip. You close your eyes and attempt to use that branch to feel around the edges of something, like lets say a chair in this example. Those little stray branches get in your way, flex, distort things, and don't ever give you the needed "feel" of what's "out there". Now imagine taking another branch. This time it's got a V" at the end of it much like a rake in shape, but imagine the open end of that V being closed off, so that it's more or less an upside down triangle. Now you can much better tell and feel the outline of that chair, without stray branches and other junk throwing off your perspective. Less slop interfering with you when you don't want or need it, but a much more defined and firm distinction to shapes when you do.

That's how I equate this field at the edges. Those wiggly lines you see in the picture is stray unintended intended signal from the coil. Resulting in more ground matrix, junk, and less distinct target sound off as you hit the side of it. That doesn't mean less coverage, because you should sweep over any target with the full center of any coil to reveal it. And, as said, the outer portion of the concentric aspects of this coil will reach out that far as well (maybe even further than your average DD), but the distinctness of the target, it's traits, separation, and so on will be much more in focus, as the line to be crossed it much more in focus and defined.

There, that should just about do it I hope. I really hope I don't go outside for a smoke and think of something else to add to these traits of these coils, as I'm sure you do as well.

 

[synthnut]

Critter.
Interesting theories !!...... I'm going to try to take a stab at what you have already theorized , and add a little bit of what I am thinking to go along with your theories ......It's hard to put into words and I would have to try and draw some diagrams of what I am talking about to make my thoughts more clear , but for now ,I will just use words .....I am going to be making up some names for area's of the detection field that I will be discussing ...... For example , I am going to be calling the area of the coils center from front to back , the "CENTER POWER FIELD " .... The concentric part of the Center Power Field , I will be calling the "EGG" .... I am envisioning the area, or mass of these CPF's and Eggs give off certain tones ....The larger the mass or area , the deeper the tone ...... Sort of like guitar strings .....Skinny strings , higher pitch .....Fatter strings , lower pitch ....What I am also pictureing is the more mass or area of the CPF's and Eggs, the more feedback it will produce , so a larger area will produce more feedback from the soil .....Going further , I see that WIDER CPF' s and Eggs take more time to travel completely over a target, gving it a more drawn out tone , and with the addition of the analog circuitry , and the larger area of these CPF"s and Eggs , you end up with a deeper , longer , smoother tone from this setup ......Put all this area on top of bad soil , and you also have more feedback from this bad soil, and therefore will have to run a lower sensitivity .... What I am picturing in my mind is that the 10 inch coil has a very wide Center Power Field and also a wider Egg ..... It has a very large area , and can easily get overwhelmed with too much sensivity .......What also happens is if you have one target next to the other , the CPF's and the EGG is taking in BOTH targets at once because of it's size ..... Now we move onto the 12 x 15 coil ....The 12 x 15 coil I'm picturing with a CPF and Egg narrower than the 10" coil .....It has less area than the 10 " coil , and is also longer , and not as wide .....This coil gives a little higher tone than the 10" coil , but takes less time to travel across the target since the CPF and Egg is not as wide as the 10" ....... This would account for the 12 x 15 coil being more quiet , and you can also run the Sensitivity higher because of less mass of the CPF and Egg ...Since they are also not as wide as the 10" coil , they also seperate better, and you will hear targets close together more easily and more disctincty ..... It's more quiet than the 10 inch coil since it's mass is spread out further, but you still can't jack the Sensitivity too high becuse there is still a lot of area to the CPF and the EGG ...... and finally the 10 x 12 coil .....This coil has even less mass, or area , than all of them ....It's tone is higher because of this, and the CPF and EGG are much more narrow than ANY of the coils mentioned here .....It takes no time at all for this coil to pass a target as the CPF and the EGG are so narrow that it fly's right over the target , and gives off a much faster reaponse .... Since there is less area , you can also run your Sensitivity much higher without feedback ....Since the CPF and EGG are so much more narrow , the seperation is more like a much smaller coil , especially on targets close together ......

My conclusion is that after all is said and done , that there is an extremely fine balance between each of these coils ....It has to do with how high your have your sensitiviy set , how mineralized your soil is , and the makeup of the soil or sand , and how each of these coils react to them .... I also think that there is a limit on each of these coils for each soil type , and each case scenario ..... The higher mass of the 10 inch coil gives it a deeper tone and it's pretty easy to overwhelm with too much Sensitivity .....The 12 x 15 has less mass and is more spread out , so you can run your Sensitivity higher ......The 10 x 12 has much less mass than both the other coils in the CPF and EGG area .....It's therefore hgher pitched and the Sensitivity can be run up much higher ......Will it be the deepest ? ....Maybe not , but it will surely slice like a knife , and seperate better than the others if my additional thoughts to yours are right ..... Remember though , with each coils CPF's and EGG's going down in area and wiidth , you will also have to raise your sensitivity up just to match the last coiil that had the wider CPF which had more area !!.....The 12 x 10 will also have less feedback to bad soil conditions ..... Now if we could only get a 6 x 8 SEF !!!....MAN OH MAN , talk about SURGICAL at depth !!........

Please understand that my thoughs could be way off base here ..... I am thinking out loud , and am in no way an Engineer that knows how these coils are made ......This is shear guessing on my part ....Whether or not it makse sense to you is entirely up to you ......Jim

Coffee can number 1 is draining fast !!!.......

 

[Critterhunter]

Pretty much jives with my thinking. Only thing I'll differ on is that the 10" standard DD coil, like other conventional DD designs, doesn't seem to have this concentric (egg) portion at the center of the coil. Also, the audio of the 15x12 seems for the most part the same type of pitch of the 10", maybe a little more base to it, but the 15x12 does provide better audio traits to me and more telling audio to targets. I for sure believe the tighter left/right detection field of the 12x10 is causing the audio to raise up, as well as making target reaction much crisper and sharp (even more so than the improved resolution the 15x12 seems to have).

Concerning depth, after searching the web and reading any and all opinions on these coils I believe that depth is more determined by the length of the coil and not it's width. At the very least if that's not completely the case then the fact that the width of the field's casing holding a wider span for more length of the coil than a round DD design is helping in some way to improve the depth of the coil. Regardless of all that, the less ground matrix or fog being taken in by less slop at the edges of the detection field would probably equate to deeper ability as sensitivity can ride higher and yet less murky ground data is being sucked in by the coil.

On smaller SEF style coils- I've always been one to favor max separation and not improved depth for a small coil. Often seeing deeper doesn't help with unmasking targets, as you are now seeing potential junk below the two targets masking each other at a more shallow level. For that reason when using the S-5 I think it's depth is outstanding, maybe too outstanding, so I find myself running in Auto or at a much lower sensitivity level to try to keep it's sites on two targets together and not what lies beneath them. I'll run it both ways at a site just to be sure, but I still feel that for seeing deeper I have larger coils for doing that. The S-5 even in Auto is lasering down to perhaps 6, 7 or 8" deep, which is oustanding because that's about max depth for most other machines on the market using a standard 9" coil or so. Auto on the S-5 seems to set higher, probably due to less RF noise being picked up by the smaller coil, as well as less ground matrix causing Auto to tone things down.

I'm anxious to get out again today for my third hunt, and this time longer than the half hour or so of both other outings. Depth ability is my next main concern in determining.

 

[Critterhunter]

I managed to get out with this coil for a little less than an hour today. I headed over to a wooded picnic/trail type area along a lake. This area has some history to it going back to the 1800's. There is a lot of stone and limestone bedrock/boulders in the dirt along here, so rather than play with a manual setting I decided to run it in Auto. If you were to adjust the GT to even a low manual setting in a place like this more often than not the setting would be too high or too low as the ground quickly changes. Things like rocks and small boulders in the soil can cause falsing and other problems, so I didn't want to deal with trying to calibrate it here. Besides, this ground has a lot of packed clay spots from foot traffic, so I wouldn't expect targets to be super deep, and I wasn't exactly looking forward to digging in this bone dry soil anyway.

While this wouldn't be a good test of this coil's depth ability, it would be a good test of it's separation, because this spot is one of the most trashy locations I've ever came acrossed. Sinkers, round and square pull tabs, foil, cans, and other numerous forms of trash has been left over the years by lazy fishermen and people picnicking. There were spots where the soil was deep rich black soil, though, and two of those types of spots is where I got my best finds for the day. Read on...

I've been playing with full volume versus lowest, checking targets in both settings to get used to full volume faster, as I almost always run at the lowest volume setting. Having heard that the techs at Minelab recommend full volume to achieve best depth on targets, I figured I better start liking it. Still, I have yet to find a deep fringe target that full volume heard while I couldn't hear well at the lowest volume setting. Pretty much so long as the machine reacts in any way (vdi change, threshold) I have absolutely no problem hearing the target well even at the most fringes of depths. Just the same, I'm going to learn to like full volume if that's what they say.

On the other hand, I find with lowest volume I can judge target depth much more easily, as the "scale" from shallow coins to ultra deep ones seems more spread out in volume for me. Not only that, but I'm having a hard time in full volume deciding if it's a deep coin and that's why it's giving me trouble to ID, or if it's a shallow piece of junk that is just coin spiking here and there. The volume at full blast makes targets real deep sound like they are right near the surface less than an inch deep to me. Perhaps it's my headphones and I'd fair better in judging depth at full volume with another pair. More than likely, though, I just need more time to get used to the new scale of volume that full volume causes. Practice makes perfect.

Anyway, because of the above facts and me wanting to compare deeper targets with low volume versus full, I began my hunt at lowest volume. Besides all that, with the amount of trash in this area on or near the surface, I really didn't feel like getting an ear blasting every five seconds. Really need something like those Sun Ray Gold headphones with a limiter to cut down on surface blasts if I am to run at full volume all the time now.

The above details are important because of the next thing I'm going to tell you in review of this coil. Hunting at the lowest volume like I normally do now makes coins only 5 or 6" deep sound softer/deeper. Same deal with surface coins, they aren't quite as loud now as they were with my other coils. I mainly chalk this up to the bit higher pitch that this coil is generating. For instance, 176 penny signals now sound like a silver dime. 146 nickle signals now sound like maybe somewhere between 149 and 152. Maybe not quite that high, but it's close. With penny signals now sounding softer/sweeter/higher pitched like a silver dime, a silver dime also has risen above that in it's own fashion. I'm pretty happy with this slightly raised tones of everything, as it resembles the QXT Pro I've trained my ears for silver on.

Back to the point...Whether the fact that coins 4 or 5" deep now sound 7 or 8" deep (again, in lowest volume) is due to my hearing (I've been told I have high frequency nerve damage), my headphones not liking that high of frequency and thus not making it as robust (loud), or if none of this matters and it's just the way this coil does things, isn't really a problem. Why? Because when I cranked it up to full volume over a few undug pennies in the 5 or 6" depth range the target volume was WAY MORE than loud enough. I don't want you to think that somehow this coil is making deeper coins sound weaker and thus it might not hit as well on real deep ones. That's not the case, it's just that they are softer/sweeter sounding more like a silver dime at depth in the case of a few pennies I dug at 5 to 7" deep. Raise the volume like most people say you should and it's not an issue at all.

Even at lowest volume I could still hear them fine and plenty loud enough, it's just that *to me* with my hearing and/or headphones and my low volume setting they were not quite as loud to me as they would have been with other coils. All this could just be perception anyway, because a higher tone at the same volume level will sound by nature not quite as loud to people, in particular if they have high nerve damage like me.

Either way, it's not an issue and I just want to make it clear. Just be aware that if you run at lowest volume that targets will sound a little deeper probably. The big bonus is that coins now sound a little more sweeter/softer/higher pitched to me, and I like that. It's much closer to what I've gotten used to on my QXT Pro, and for some strange reason I seem to be able to tell the subtle differences in a real coin versus a piece of junk that's trying to act like a coin when it's presenting it's self to me with this high of pitch. It's like the softer/sweeter/more "treble" rich tone shows off any little flaw in it's audio quality to me more when it's generating a tone at this high of frequency.

The old tone wasn't a problem in revealing it's traits to me. It might just be that my years of QXT Pro experience digging silver has REALLY trained my ear to listen to the slight differences and qualities of this high of tone, and allows me to further dissect and analyze a potential coin target more vividly. It for sure is more of a attention grabber for me. I'd also point out that this tone isn't in reality that much higher than the standard tone on the stock 10" coil, but little things like this make a difference and I swear it sounds just about as high as my QXT Pro now. A nice "sweet" like signal more crisp and sharp.

So along I go poking around between the trash and trees and get a nice sweet/soft deeper coin signal. This is where the point is about that, because I was estimating 7 to 8" deep on this coin when in reality it was like 5 or 6" deep once I dug it. Again, at lowest volume. Cranked it up to full volume and she's blasting away at something louder than I feel is comfortable for me, so don't worry about that. The target would give me a very effortless proper ID from any direction, even using the tip of the coil and wiggling at it to pinpoint it (practicing that in discrimination), then flipping over to true PP mode to confirm that the target is where discriminate said it was.

I repeated this whole ball of wax on two separate targets which happened to be in the same rich black type of soil. Both being pennies of some sort, both reacting the same, and both ranging from 5 to maybe 7" deep. On further inspection on these two separately dug targets, I can not tell if they are wheats or indians. If they turn out to be wheats they are for sure some of the most crusty wheats I have ever dug, because usually I only see the odd indian head penny get this bad in certain grounds. Not all grounds, as I've dug indians in pristine conditions as good as a modern penny. It all depends on what kind of soil they've been sleeping in, if fertilizer has been spread there, etc. Even in Auto these two different targets were effortless to achieve easy IDs on from any direction, without any kind of "running away" on me where I have to work to bring the proper ID back. That may not sound like a huge feat at those depths to some of you, but it is in this particular soil with with mineral/hot rock type content. Any other machine with maxed out sensitivity would from my experience not want to hold on to these targets probably as well at this site, even at these lessor depths.

Now I've got to head off to a known deep coin spot and see what gives with this coil. I also plan to bring along my 10" coil and compare each to each other on some freshly buried coins at fringe depths, on edge, etc. Yes, I know that doesn't show true undug results, but let's be honest here. Which ever is the stronger of the two in certain respects (depth, ability to hit stuff on edge, etc) is going to still show through for the most part. I'm not saying that's going to tell you exactly how deep the coil will go on undisturbed targets. I know one should expect much better and deeper responses in that case, but it's still useful as a measuring stick to see who seems to be out doing who in certain respects.

I'd like to do some coin garden testing but I made the mistake of burying my coin garden in my backyard right under some power lines. The results are that only lowest manual or Auto will work there, and even then it can be touchy. I've got to move that coin garden to a more ideal location sooner or later.

By the way, this spot was I hunted today was so trashy (one of the worst I've ever seen) that I decided to run my notch. I waited until I found a 165 tab signal and then slowly raised the notch while sweeping over it until it just killed the audio from that. That would kill down to 152, eliminating about 84% of all round and square tabs. I then found about a 120 junk target (probably a piece of aluminum) and raised discrimination slowly while sweeping over that until it just killed it. Results are that now you've got the nickle zone open (139 to say 14, a hair above that, and below it down to about 120 to see any solid, repeatable, smooth, potential gold ring readings in that range. And, above 165 you've got it open of course all the way to 180 to dig potential keepers in that range. In severe cases one could raise the discrimination up to just about 139 and really kill troublesome targets in that range while still getting nickles, and then fine tune the notch up to say 169 or dropped down to where it just starts at say 149 to kill junk like that. Still yet, some people will just crank the discrimination dial all the way to the top in really bad spots. Now anything from penny to silver is the only targets that will be accepted.

 

[Critterhunter]

Almost forgot to add that after using this coil in the woods today it's obvious that it's easier to sweep over the ground clutter than the stock 10" coil. Strangely enough I felt that way about the 15x12 too. Something about the coil webbing makes it harder for branches and such to crawl up inside the coil and snag it. Although it's got more "holes" in it than the 10" coil, the space between those holes is less. It slides over the ground much more easily without every little branch grabbing ahold of it.

 

[synthnut]

The reasoning behind having your volume up is so that if there are REALLY deep targets that whisper to you , and are harder to hear since they are so much deeper, that you will hear them .....If your already hearing REALLY deep , hard to hear , targets , than I don't see any reason that you should have your volume up that loud .....Keep your threshold low and keep your volume at a level that is not blasting you out ....If you can hear the nuances of a target better at lower volumes, then by all means lower the volume ...... A lot DOES depend on what phones you use ....I have a couple of pair of the Koss headphones that they give you with the E Trac ...I can run those phones at 3/4 volume and they are loud, but not to the point of discomfort .......I also have a pair of Audio Technica Studio phones that are much more telling , and if you run those at 3/4 volume, they will take your head off !!!..... They are not as smooth and bassy as the Koss phones ....They have more midrange and a brite/sharp top end that REALLY lets you know that there is SILVER IN THE GROUND !!!!...... Maybe it's the fact that a lot of phone that are made, are just not that efficient with the Sovereign .....Maybe they really DO need to be jacked up to hear the finer nuances of the tone ....I can tell you this much , I can hear so much more of the tone with my AT phones than the Koss phones, and at a much lower setting on the volume knob ....I really think that I am going to look into finding out what controls the audio tone inside the Sovereign ....Since wearing these Audio Tech. phones , I"m convinced that I will be better served with a higher pitched audio ....... If your ears are anything like mine , you are probably enjoying the sharper tone of the 10 x 12 .....I'd be willing to bet that its a lot more telling than the smoother sounding coils ....Not as smooth, but much more character to the tone. and a lot more expressive ..... Jim

 

[kered]

Me not being a novel writer in my explanations like some the way i see things is as follows
I think there is a difference between having the volume up high on the detector and adjusting for comfort on the headphones to having the volume low on the detector and full on the headphones like in the case of Koss and the likes with no volume control, you only have adjustment on the detector. I find that the volume control seems to be a sort of 2 in 1, as well as target volume has some degree of volume gain in it, ie a threshold where its decided if a target is a target or not, with lower volume/gain its decided as not and with higher volume/gain it is a target. (On the etrac these controls are seperate)
With the volume up full or near full the detector is presenting all targets that it can detect be it loud surface or faint deep targets, turning the detector volume down will diminish the deep faint signals till some disapear completely as they fall below this target or not threshold. Having volume control on the headphones you can then set the lowest/faintest targets till you can still hear them and thus lowering slightly the surface blasts, having a limiter on sure helps as you can still hear the faintest but aren't blasted out by surface stuff.
Having the volume low to me is like having the threshold too high, targets are lost as they don't break through as they are not classed as being a target.
Hope that makes sense

 

[synthnut]

Kered,
I would totally agree with you , but what if you are already hearing these signals WITHOUT the use of higher gain/volume on the detector ? ...... I guess it doesn't hurt to have the option , and in some cases it's surely needed, but in other cases , it's not ...... If you're already hearing dimes in the 10" range pretty clearly, how much more do you need to hear ? .....If you can hear targets clearly at the depth that the machine can max out at , do you really need more gain or volume.....In Critters case , it seems like the louder volume/gain is hurting the way he hears the nuances of the tone that the target gives him ....I'm no Novel writer either , and can't for the life of me thnk of who you are talking about !!..... .....Any ide's Critter ?....

 

[Rick(ND)]

I have always run my volume up to max on the detector and max on my headphones too as i need the volume for my bad hearing. Now with that if I didn't turn my detector volume all the way up I notice as soon as I hit my first target as it just don't sound right,
I believe in this max volume on the detector and setting the volume on the headphone to what is comfortable if you want the deep targets as I have seen it happen as in this old park a guy that normally can out hunt me wasn't getting those deep signals I was getting. The next target I got that was real weak, but yet with my bad ear could hear it and was repeatable so I shut off my Sovereign and had him try it with his Sovereign and he didn't hear it. I switched my headphones with his as he used a different brand and tried it and sure enough I couldn't get it, so I seen his volume wasn't maxed out so I maxed it out and tried it again. Now I could hear the signal and had him try it with his headphones and he could get it now. This is why I agree with Minelab to run max volume on the detector and set your headphones for comfort if you want the deep targets. I feel it works for me even with my bad hearing.


Rick

 

[Critterhunter]

I'd have to agree with Kered's logic behind the volume. That's pretty much the way I think about it. But at the same time I also agree with Synthnut, so at this time I'm trying it both ways more to see what gives. Excellent pros and cons by both of you. Bottom line is why risk loss of depth when there is no downside to just going full volume? Well, of course the downside for me right now is it's way too loud on surface trash, so I should probably check out those Sun Ray headphones. I can totally see Kered's logic as that's the theory I've derived in my head as to why the Minelab techs say to use full volume. It may be that the deepest of the deepest of targets will some how sound off at full volume when low doesn't allow the signal through. At this time I just keep trying it both ways and seeing if full really does find a target that low can not hear. That's all I can do until another pair of headphones comes along.

But at the same time Synthnut's reasoning about lack of target quality also weighs on my mind. It's not just about the surface blasting, it's the loss of target traits that I seem to get with full volume. I'm sure it all comes down to headphones, as I believe this Sony Studio phones with much lower ohm specs than Minelab recommends tend to blur target quality when the volume is way up. At the lowest they are just low enough in volume for me to tolerate and have much better audio traits, but with foam stuffed in the air muffs to lesson it a tad more down to a comfortable level at lowest volume. Ever turn a stereo up to the point where the audio from the speaker starts distorting and losing audio quality? That's what seems to happen to me if I crank the volume up with these things.

Rick, your reasoning jives with Kered's and I'm one to believe that this is the strongest arguement for using full volume on the Sovereign and then adjusting it down on the headphones. I can totally believe that, just haven't seen it for myself.

 

[synthnut]

If we are talking about headphones with a volume control on them , then YES by all means I also agree with Kered ......I didn't think we were talking headphones with a volume control .....If you have no control on the headphones , and you turn your volume up to the point that it distorts simply because Minelab tells you that this is the best way made no sense to me ...However if you turn the machines volume all the way up, AND THEN control the volume from the phones, then YES this is the best S/N ( siignal to noise ) ratio you will get and the most clear tone ...... I understand a lot of this from the musicians point of view .....In this case it's like having a nice tube amp, and you have a Master Volume, and a Preamp volume control ....To get the most clean tone from your guitar , you would turn the Master Volume all the way up , and then bring in the Preamp volume last ......This will give you a clean tone ...If you want an overdriven tone, you keep your Master low , and turn your preamp volume up high ...You then have a more distorted overdriven tone .......The detector is the master volume and the phones are the preamp volume in this case ......Bring the Detector up high , and bring the phones up only to what you need ......This gives you the cleanest tone !!..... and Kered ....YES I think that there is a certain amount of signal gain to be had turning the volume all the way up also .....This , not the same as volume , but signal gain ......Jim

 

[kered]

Critterhunter, I'm sure you could find a limiter circuit somewhere on the net and rig up an addon to your phones you have, a lot cheaper than buying new phones, just an idea

 

[Critterhunter]

Synthnut, good explaination. I agree. Kered, I'll check into that. I remember years ago they used to sell a little box for detectors that your headphone plugged into and it features this. It both boosted faint signals and limited loud blasts. Think it was called a Depth Doubler or something like that.

 

[synthnut]

Something that might be of interest ....I need to look around the net for it ....I think that maybe Koss or some other headphone company made it ....It's a mini EQ system .....Very small with sliders to adjust the EQ ......It was a small inline box .......Jim


Here ya go ....

http://www.amazon.com/Koss-EQ50-3-Band-Stereo-Equalizer/dp/B00005UPF6/ref=sr_1_1?s=gateway&ie=UTF8&qid=1285189918&sr=8-1

 

[Critterhunter]

Only problem with that is no limiter, I don't think.

I went out for another one hour hunt today between things I had to do. I headed to a small lot that I've worked to death over the years. "Iffy" signals are really found at this site anymore, so I was happy to see that the 12x10 seemed to come up with a bunch of new iffy signals to check out. I attribute this to the fact that it must be working harder at trying to pull a decent signal out of targets that would be borderline on other coils.

I didn't do much digging, but rather a bunch of looking for that "cherry" signal, or at least something I felt like taking a chance on. This spot is loaded with iron and so I spent much of my timing wandering around REAL SLOW, hoping this coil would unmask a coin in that mess. Large portions of this site are one giant null, so I took the sensitivity down to just below 3PM to try to keep the iron from glaring off what I wanted to look at. I should have ran it in Auto here because I find Auto will maintain the threshold better in these worst of the worst locations.

Anyway, the only keeper wasn't really a keeper, but it proved to me that this coil is very good at getting in there tight and unmasking coins. I was getting a large iron signal with a halfway decent coin signal mixed right in with it. By using the tip of the coil in discriminate mode I was able to isolate the coin signal and work it to judge response. Decent enough from one angle, so I shifted around 90 degrees and nipped at the target with the tip of the coil again. Sure enough, pretty decent penny signal still, and it sounded roughly 5 or 6" deep so I was hoping for a perhaps an Indian.

I dug down and at about 6" out pops a penny that wasn't even a wheat, but I was still happy with how well this coil snipered that coin out of that iron. While I've dug coins mixed with iron (usually nails) on the Sovereign more than other machines right in the same hole, this was I'd say the most close I've ever seen a coin and a very large iron signal to each other by investigating with the tip of the coil. I could literally move just an 1/8th of an inch or so off that coin and now be into a total iron null.

I hope you know what I'm saying here. I've dug nails and such right in the same hole with a coin on the Sovereign, but when we are talking big iron mostly all around a coin like this I've never seen both signals so close to each other where the tip was able to get in there and sniff them out and sound them off separately. Normally rather than show both targets that close to each other when the iron is this large, I'd usually get a coin signal mixed with nulling or other garbage signals.

On other occasions when the iron was this big or it was nails right in the same hole the Sovereign would still do it's thing and make the coin sound off thanks to Iron Mask, but this was the first time I've seen big iron this close and was able to see the separation of the two signals with careful coil placement in that tight of proximity to each other. Most of the time you'd get a null, then hear the coin in the signal come through thanks to Iron Mask.

This time it felt like I was using a scalpel to slice the two targets apart and investigate them separately. It's nice to have the ability to do some of the work for Iron Mask when you are talking this kind of precision. I'm not saying you can't split a coin and a nail apart that are very close to each other with other coils on the Sovereign. I'm able to do that. Thanks to DD coils it's very easy to do so long as you use the DD portion of the signal and hack at them properly, or wiggle in the right spot. It's just that I've never seen such a large iron signal (like coffee can size) and been able to see and isolate a coin signal right off the edge of it without getting the null mixed in and having to rely on Iron Mask to work it's magic. In a normal situation this large of an iron signal would overwhelm the coil and draw it's self into it, resulting in Iron Mask having to take the blended signal and break it apart so it could report the coin portion of it. It almost feels like the tip of this coil is like a pinpointing probe that can look like a laser between targets.

After using this coil today things are starting to gel more with it. I can honestly say that the 10" Tornado, S-5, and 15x12 are more similar to each other in the way they react and the reasons for it, while the 12x10 is much more different and stands apart from those coils in a much more distinct manner. Oh, it's not so much different that you'll feel you are using a completely different machine. Well, in a way it does feel like that I guess. What I mean is that the 12x10 will do things the same way as these other coils, it's just a little different in how it goes about doing it. More to the point, I'll use a bad analogy and say the language it speaks with has a heavy accent. With it's higher pitch it just talks a little different, and reacts a little different with it's much more responsive super tight detection field.

Don't think you can just slap this coil on and it's going to feel like a comfortable old shoe. It some ways it will, but the 15x12 or S-5 will give you that feeling more, being more similar to the stock 10" in the way they talk and act for the most part. The 12x10 is much more different. Not harder, just different, and I'm more than willing to put the time in to understand how it wants to tell me things because I feel once learned the potential it offers is outstanding. Even if this coil doesn't show me greater depths, it's better coverage than the stock coil and seemingly greatly enhanced ability to split targets apart (without having to make you or Iron Mask do all the work) is something to behold. Sure, you can split things apart yourself with the 10" coil or 15x12 (which is better at doing that in the left/right perspective than the stock coil), but it's far less work to make the targets isolate from each other with the 12x10. More "effortless" I would say.

Here's another odd observation. I talked about coins sounding slightly softer, but explained that more than anything this was probably due to the higher pitch being generated. The weird thing is that they don't get all that much softer as they go deeper. It seems like past 5 or 6" coins in the 8 or 9" range don't sound all that much softer. I noted this a long time ago with the GT when I first started using it. It's almost like once a coin gets past 7 or 8" some kind of amplifier kicks in and amplifies the audio signal. It's weird, because sometimes I can hear "white noise" in the background while wiggling over the target as this greater volume kicks in. I've seen that on the other coils (more so the stock coil), and now I'm seeing (hearing) it with the 12x10. I have no explanation for this, as I never heard this "amp" type deal with the 15x12, meaning I never heard this "white noise" or whatever in the background. I wonder if this might some how be related to the types of pre-amplifiers used in the RX coil circuit inside the coil? I doubt it, more than likely it's something internal going on inside the GT. Just odd that I would hear this with the stock coil, not with the 15x12, but now again with the 12x10.

One final note for tonight. I'd say the pitch is even higher than I first thought. Several times I'd hear what I thought was a penny signal and look down at the meter to see it reading 167 to 169 or so. It's not a big deal for me and in fact I prefer the higher tones of everything. Just takes a little time to get used to the new scale of pitches being put out.

 

[synthnut]

Critter,
I run an S-5 on my E Trac and the way you are describing the 10 x 12 SEF , it sounds more like when I'm using the S-5 on the E Trac .... The S-5 doesn't have the higher pitch , but it's a very surgical tool especially in trash .... I can zip around all kinds of things using thiat coil .... Because of the size of the coil ,it's very quiet too !!.... I'm very surprised that you are not seeing a similarity in the S-5 and the 10 x 12 SEF ..... I can also raise the Sensitiivity of the S-5 moreso than the Stock Pro coil and bring it very close to the depth of the Pro Coil ..... Your findings are somewhat confusing me ...... then again , that's not hard to do sometimes !!

Kered ,
Do you get the same high pitch tone using your 10 x12 also ? ..... I'm not doubting what Critter is hearing , but I am questioning if maybe there is something different with his coil since he did have to do some repair to it ......Then again , I've heard with my own ears how different these SEF cols can be and how they defy rational reason ..... Jim