The Combined vs 50 Condictive is just the amount of tones you'll hear. The Combined pattern uses a quite different setup (discrimination without making a blacked out pattern) than the stock COINS Discrimination which does have blacked out area pattern.
One would have to use the RELIC pattern to have very little discrimination and a mostly opened screen with just some blacked area out at the bottom of the screen in the lower FERROUS zone.
Combined your leaving the screen wide open then boxing off the lower section of the complete left to right of the screen with a low tone then setting 4-5 sections vertically across the screen on top of that for the different tones for the targets that fall into each box instead of 50 tones from left to right on the screen where the cursor lands.
Whatever targets fall into the blacked out area generally you will see the cursor but not hear any sound or maybe just some iron sounds, chirps etc.
In this case sounds 4 vs 50 and discrimination pattern in Conductive vs none or very very little in Combined 2 different things hence different results.
First I hunt in 50 conductive then I used to go back over the area in two tone ferrous with my Etrac and see what I missed.
Now with my CTX you can also go back yet again or skip TTF and instead go hunt in the Combined mode and see if there is still anything further that was missed.
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