What I describe in my original post makes sense to me until I jewelry hunt in the tot lots. Then, I question my thinking.

When I turn the sens down to get closer into the playground equipment, am I actually reducing "depth" capability to the sides of the coil or does the detector know the pole is there but just not give an audio response until I force the issue by reducing the distance to the coil? If this is true, then in parks or ghost towns it must be true also? The detector knows the coin is there but I've just muted it from telling me so?

Hard to know where the "sweet spot" is on this setting.