Concentric, mono, DD coils and VLF, PI detecters...?

[controlfreq]

OK, this has probably been beat to death here, but I'm not finding a lot just yet (still looking.) I am trying to get an idea of what the differences in the coils are and when to use which. When I bought my Infinium it came with the stock DD and an 8" mono. I understand that the larger coils usually get better depth and the smaller have better resolution for smaller targets and desc but what exactly are the differences in their specific uses? Exactly what are the fortes of these coils respectively?

At the same time, I'm getting pretty serious about buying an AT Pro for those places in which the Infinium is less than optimal. Again, it has several different optional coils with the stock coil being a DD. I saw where people are using the smaller 5x8 DD for better discrimination ability and that would make sense, but what is the concentric used for.

Presumably these two animals are different enough that the coils are not interchangeable (although hopefully the earphones are...)

Thanks
John

 

[controlfreq]

OK, looks like a big chunk of this information is on the Garrett website (duh! moment.) Still would like to hear anything you guys have to add.

Thanks
John

 

[BigCatDaddy]

I've heard that the 'Fin phones won't turn the ATP speaker off...but then again, that's just hearsay. The coils are definitely not interchangeable. The DD's give better target separation than the concentrics and allow you to detect in highly mineralized soil. The concentrics are not as susceptible to bottle caps reading as good targets, although the Iron Roll audio on the ATP will help you identify them. Smaller coils allow for more Sens. to be run without falsing and allow you to get closer to large metal objects like playground equipment.