Critterhunter
New member
I've got asked this privately a lot in the past, and just got the same type of question in a PM again. Already said it countless times before, but figured I'd re-post that question (scrubbed of the name to keep the asker anonymous of course) and relay my experiences with both coils here...
"Critter, Did you find that you get more depth with the 12x15 SEF than wit the 10x12 ? If so what's the difference in depth."
I first owned a 15x12 and found it didn't seem to go as deep as the stock 10" Tornado in my mineralized soils on coin/ring sized targets. Also found that it seemed to give best depth, or at least ID/tone at depth, if I lowered the sensitivity much lower than what was max stable. I suspect the reason being that the 15x12 was just too big and beyond the point of no return to gain depths on coin/ring sized targets in my soil minerals, and that by lowering sensitivity it lit up the ground less and washed out targets less with the ground signal.
I've always heard that in a DD about 14" in physical *round* size was about the max limit to still gain depths on coin/ring sized targets, and beyond that you'd start to lose depth. In concentrics the rule of thumb seems to be about 10.5" to *maybe* 12" in size, depending on soil, as they ride on and suck up more ground signal than a DD of similar size in general.
The 15x12 I owned did seem to get more depth on coin/ring sized targets in my mineralized sands than the stock 10" Tornado, just not in my mineralized soils for some reason though. Why I don't know. Maybe my beaches particular minerals were just more to it's liking than my land minerals?
The official field test when the SEFs first came out showed the 15x12 was deeper than the 12x10 on roughly crotal bell sized targets and bigger. Here's a picture of a crotal bell...
[attachment 261010 CrotalBell.jpg]
I wish they would have described the exact size of that bell, as they come in different shapes and sizes, but I'd suspect it was roughly close to a half dollar in size. The ones I've dug in the past (just looked at one in my finds drawers to refresh my memory) are probably about the size of a half dollar. Maybe a hair bit smaller in diameter. That official test showed that the 12x10 was deeper on dime or sub-dime sized targets if I remember right, which makes sense to me even if the sizing descriptions aren't exactly spot on.
I've found the 12x10 seems to be deeper than both the 15x12 and the stock 10" Tornado on land for me in my soils, and while the 15x12 was deeper on coin/ring sized targets in the sand than stock, it looks to me like the 12x10 is still deeper yet on those size targets in the sand, just like it appears to be in my soils.
The 12x10, for one, will wiggle up proper ID/tone on dimes or pennies in say the 8 or 9" depth range in bone dry conditions much easier than the 10" Tornado without as much "effort" for me, and the 15x12 seems to have trouble with that unless I lowered the sensitivity much lower, like say down from 9PM max stable to say 2 or 3PM in sensitivity, and even then it didn't seem to get the depth of the stock 10" Tornado or the 12x10 in my soils. Only on the beach did the 15x12 seem to get deeper than the stock 10" Tornado for me on those coin/ring sized targets.
The 15x12 is a very stable coil for it's size. The 13" Ultimate is not as stable around minerals or EMI, but it's unique enough in a larger coil, compared to my 12x10 or even conventional round DD coils, that I want one in my line up to replace my loaner for days I'm in the mood to grid large open areas even faster than the 12x10's nice improvement over stock in that respect.
In the marked head to head undug targets in the field, that loaner so far was able to keep up with the 12x10 on deep stuff, but I'm still not sure the Ultimate is as deep, and for sure it's not as easy to work around and isolate targets in trash over the 12x10. The Ultimate has a sharp DD line like the 12x10, but the 12x10's unique shape makes it much easier to work in between trash without needing to re-position myself around it as I do with the Ultimate.
On those marked undug targets, the Ultimate going first would often have me marking something deep I thought might be a coin, but when I swapped to the 12x10 right away I could tell it was an iron false or some other piece of junk by it's traits. Not saying the Ultimate is easier to fool. Might just be I'm not used to the Ultimate's language as much as I am the 12x10. I would dig these up to confirm them and sure enough the 12x10 was always right in my suspicions.
Might be though the Ultimate will more "easily" say "coin" on fringe coins, being easier to convince, but I have yet to see that. The 12x10 is louder than the stock 10" Tornado at depth, but the Ultimate is even louder. But, at least in air tests, the Ultimate gets about a half inch less depth at full sensitivity (maxed out for both coils in a low EMI environment) than the 12x10 when I precisely measured that.
The 15x12 without a coil cover is lighter than the 10" Tornado with a coil cover if I remember right (refer to the coil weight chart thread in the coil sticky), but for sure the 13" Ultimate is even lighter on the shaft and feels much more feather like to use for a coil of it's size. Both the 12x10 and Ultimate are very near each others weight without coil covers, a good bit lighter than the 10" Tornado, and the 12x10 for me on a scale is a half ounce lighter than the S-12 without a coil cover.
I would say if you have a 15x12 but not a 12x10 and are shooting for max coverage in large fields or wide open beaches and not so much max depth on coin/ring sized targets, then you've got an outstanding coil for that. But if you already have a 12x10 and don't have a 15x12, then if you want an even bigger coil for coverage if not necessarily max coin/ring sized depth then go for the Ultimate as for a larger coil to sit along side your 12x10.
Don't know yet if it's as deep as the 12x10 for me in my soil, but based on what I've seen with marking targets in the field with poker chips and then swapping coils, the Ultimate may be pretty close depth wise. I've found though that same site/same day, the Ultimate often won't allow nearly as high of sensitivity settings as the 12x10 for either EMI or mineral reasons (seen one or the other reason at some sites), and doesn't seem as stable as the 15x12 in EMI/minerals from memory of when I owned one as well.
I just feel owning a 12x10 makes the 15x12 too much of a duplication for me with no obvious perks, other than more coverage or say going after large deep relics or caches maybe, but the Ultimate will do that too and is so different than other round coils that I just want one back in my line up to replace the loaner I have. Way I see it if I'm swapping out the 12x10 on the shaft for a larger coil in big/wide open areas I want to grid even faster for the day, then I'd rather have something different than the unique traits of the 12x10 or the more "conventional round" traits of my 10" Tornado, and to me that's the Ultimate.
I have heard some say the 15x12 gives them more depth in sand on coin/ring sized stuff then their stock 10" coils, but I don't remember if those were 10" Tornados or the old heavy 10" BBS coils. All depends on your minerals I think. In mine I think the max DD coil size in a *round* DD coil might be 12 or maybe 13" in max size to still see gains in depth on that coin/ring sized stuff. Don't even think a 12" round DD coil will achieve the same depths as my 12x10 in my soil/sands. Only reason why I suspect the 13" Ultimate might is that it seems to have a very tight field and unique design layout compared to a typical round DD. It reminds me of the Pro Coil in it's looks, and I wonder if there might be something to that...
"Critter, Did you find that you get more depth with the 12x15 SEF than wit the 10x12 ? If so what's the difference in depth."
I first owned a 15x12 and found it didn't seem to go as deep as the stock 10" Tornado in my mineralized soils on coin/ring sized targets. Also found that it seemed to give best depth, or at least ID/tone at depth, if I lowered the sensitivity much lower than what was max stable. I suspect the reason being that the 15x12 was just too big and beyond the point of no return to gain depths on coin/ring sized targets in my soil minerals, and that by lowering sensitivity it lit up the ground less and washed out targets less with the ground signal.
I've always heard that in a DD about 14" in physical *round* size was about the max limit to still gain depths on coin/ring sized targets, and beyond that you'd start to lose depth. In concentrics the rule of thumb seems to be about 10.5" to *maybe* 12" in size, depending on soil, as they ride on and suck up more ground signal than a DD of similar size in general.
The 15x12 I owned did seem to get more depth on coin/ring sized targets in my mineralized sands than the stock 10" Tornado, just not in my mineralized soils for some reason though. Why I don't know. Maybe my beaches particular minerals were just more to it's liking than my land minerals?
The official field test when the SEFs first came out showed the 15x12 was deeper than the 12x10 on roughly crotal bell sized targets and bigger. Here's a picture of a crotal bell...
[attachment 261010 CrotalBell.jpg]
I wish they would have described the exact size of that bell, as they come in different shapes and sizes, but I'd suspect it was roughly close to a half dollar in size. The ones I've dug in the past (just looked at one in my finds drawers to refresh my memory) are probably about the size of a half dollar. Maybe a hair bit smaller in diameter. That official test showed that the 12x10 was deeper on dime or sub-dime sized targets if I remember right, which makes sense to me even if the sizing descriptions aren't exactly spot on.
I've found the 12x10 seems to be deeper than both the 15x12 and the stock 10" Tornado on land for me in my soils, and while the 15x12 was deeper on coin/ring sized targets in the sand than stock, it looks to me like the 12x10 is still deeper yet on those size targets in the sand, just like it appears to be in my soils.
The 12x10, for one, will wiggle up proper ID/tone on dimes or pennies in say the 8 or 9" depth range in bone dry conditions much easier than the 10" Tornado without as much "effort" for me, and the 15x12 seems to have trouble with that unless I lowered the sensitivity much lower, like say down from 9PM max stable to say 2 or 3PM in sensitivity, and even then it didn't seem to get the depth of the stock 10" Tornado or the 12x10 in my soils. Only on the beach did the 15x12 seem to get deeper than the stock 10" Tornado for me on those coin/ring sized targets.
The 15x12 is a very stable coil for it's size. The 13" Ultimate is not as stable around minerals or EMI, but it's unique enough in a larger coil, compared to my 12x10 or even conventional round DD coils, that I want one in my line up to replace my loaner for days I'm in the mood to grid large open areas even faster than the 12x10's nice improvement over stock in that respect.
In the marked head to head undug targets in the field, that loaner so far was able to keep up with the 12x10 on deep stuff, but I'm still not sure the Ultimate is as deep, and for sure it's not as easy to work around and isolate targets in trash over the 12x10. The Ultimate has a sharp DD line like the 12x10, but the 12x10's unique shape makes it much easier to work in between trash without needing to re-position myself around it as I do with the Ultimate.
On those marked undug targets, the Ultimate going first would often have me marking something deep I thought might be a coin, but when I swapped to the 12x10 right away I could tell it was an iron false or some other piece of junk by it's traits. Not saying the Ultimate is easier to fool. Might just be I'm not used to the Ultimate's language as much as I am the 12x10. I would dig these up to confirm them and sure enough the 12x10 was always right in my suspicions.
Might be though the Ultimate will more "easily" say "coin" on fringe coins, being easier to convince, but I have yet to see that. The 12x10 is louder than the stock 10" Tornado at depth, but the Ultimate is even louder. But, at least in air tests, the Ultimate gets about a half inch less depth at full sensitivity (maxed out for both coils in a low EMI environment) than the 12x10 when I precisely measured that.
The 15x12 without a coil cover is lighter than the 10" Tornado with a coil cover if I remember right (refer to the coil weight chart thread in the coil sticky), but for sure the 13" Ultimate is even lighter on the shaft and feels much more feather like to use for a coil of it's size. Both the 12x10 and Ultimate are very near each others weight without coil covers, a good bit lighter than the 10" Tornado, and the 12x10 for me on a scale is a half ounce lighter than the S-12 without a coil cover.
I would say if you have a 15x12 but not a 12x10 and are shooting for max coverage in large fields or wide open beaches and not so much max depth on coin/ring sized targets, then you've got an outstanding coil for that. But if you already have a 12x10 and don't have a 15x12, then if you want an even bigger coil for coverage if not necessarily max coin/ring sized depth then go for the Ultimate as for a larger coil to sit along side your 12x10.
Don't know yet if it's as deep as the 12x10 for me in my soil, but based on what I've seen with marking targets in the field with poker chips and then swapping coils, the Ultimate may be pretty close depth wise. I've found though that same site/same day, the Ultimate often won't allow nearly as high of sensitivity settings as the 12x10 for either EMI or mineral reasons (seen one or the other reason at some sites), and doesn't seem as stable as the 15x12 in EMI/minerals from memory of when I owned one as well.
I just feel owning a 12x10 makes the 15x12 too much of a duplication for me with no obvious perks, other than more coverage or say going after large deep relics or caches maybe, but the Ultimate will do that too and is so different than other round coils that I just want one back in my line up to replace the loaner I have. Way I see it if I'm swapping out the 12x10 on the shaft for a larger coil in big/wide open areas I want to grid even faster for the day, then I'd rather have something different than the unique traits of the 12x10 or the more "conventional round" traits of my 10" Tornado, and to me that's the Ultimate.
I have heard some say the 15x12 gives them more depth in sand on coin/ring sized stuff then their stock 10" coils, but I don't remember if those were 10" Tornados or the old heavy 10" BBS coils. All depends on your minerals I think. In mine I think the max DD coil size in a *round* DD coil might be 12 or maybe 13" in max size to still see gains in depth on that coin/ring sized stuff. Don't even think a 12" round DD coil will achieve the same depths as my 12x10 in my soil/sands. Only reason why I suspect the 13" Ultimate might is that it seems to have a very tight field and unique design layout compared to a typical round DD. It reminds me of the Pro Coil in it's looks, and I wonder if there might be something to that...
