Jason
The de mode will not go as deep as the two new modes, With the 5" coil set it up on a bench, and do an air test, like I said it isn't the best way, but it will give you an idea. You will find that the cl will do a little better than the pb, then try you de mode with that same target and coil and I'm sure you will see the difference...Then real world, go out and dig a hole, make sure you sanitize the area for iron, to keep it simple. Then drop your target in the hole and read it with the DE mode first. Continue this by making the hole deeper till you can't hear the target in DE. Then start there with the pb mode till you get as deep as you can hear it, then put the cl mode to work. Fill the hole each time you are testing to see if you can hear the target. Like I said I relic hunt and the 5" will out do the 11 dd in heavy Iron and separate better, but even then this set up really gets down in the ground.. Really the new LTD there is no use I can see to using the other modes anymore. I hunt if I can 99sen, 0 disc, 4 tones, pb or the cl depending on area, 11 dd most of the time, lots of iron 5". If my area is really paying off I will hunt the 5" only and yes it is slow but very deadly.. In an old camp that I had given up to even hunt, was a new virgin camp to the first trip in with the F 75 first generation. My partner and I dug 3 $1 gold coins in the first few weeks in that old " hunted out camp" if you want to see then look on page 16 of the world treasure news,lower left hand corner.. Yes I have tried mono tone and 2 tone, but I find it easier to hear the non ferrous tones mixed in the ferrous tones. The dollar that I dug was in the middle of a 5'x5' area that must have been a hunt site build with ammo boxes for it was just loaded with nails but the 4 tone picked the non ferrous tone out. When I dug the target I was TERRIFIC LY surprise that is was the gold coin at 5 inches deep with nail next to it and all over it. Keep in mind it wasn't a jump out and bit you tone, but enough to tell you there was a non ferrous target there.. Sorry for the long post... Keep on digging it is there to find....