Funny you mention having multiple detectors to be able to switch coils quickly.

I was thinking about recent posts here and there about what improvments to detectors can there be?

1. We could get more depth, although I doubt it is neccesary or worth it. As Minelab claims "50% more power for the Manticore", that relates to 5% more actual depth! (the field expands at the cubed root of power). 2 problems with it - reduced battery life, and dynamic range reduction. I've seen a few videos on the Manticore at work in heavy iron - or any large amount of target for that matter. That extra power gets reflected into the receiver and can lower its sensitivity to small targets, unless they've engineered a better front end.

Of course the age old PI-VLF combo. PI depth with VLF discrimination. No one seems to have perfected that yet.

2. How about switched coils? Somehow design coils such that they can be switched in size, say from 3" to 10", and concentric to DD?

3. Even faster recovery speed. Costs more and eats more power, but if made super fast, the TID could display 2 different numbers one for each target.