Auto plus 3 sensitivty works. But not as deep vs manual. Manual Sens of 26 is where CTX seems gets a bump for depth vs lower manual sensitivity setting if 25.
Etrac seems works like this too.
Emi the auto plus 3 sens CTX May run quieter. In trashier sites could be better than higher manual sensitivity. One thing about higher manual sensitivty I have noticed. Shallower finds 1-4” deep, seems can me missed easier running higher manual sensitivty vs running auto plus 3 sensitivity.
To reach 9.5” plus depth say on silver dime. Auto plus 3 not recommended imo.
Higher manual sensitivty will make CTX false more on iron. But detector will alert on deeper nonferrous.
Good trained ear one will get use to and can dentify iron though.
I was hunting with a gent some time ago (member here). This detecting scenario was actually videoed and posted here. A site with a lot of iron. Gent was using 6” coil on CTX. On a Xp Deus located target his CTX wouldn’t detect. Now the video doesn’t show what he did. He actually quickly toggled to manual sensitivty then the CTX would give signal.
Based on my experiences.
A manual sensitivity setting of 22 is odds on favorite deeper (slightly) than auto plus 3 sens setting even if the CTX is tracking at say 27 sens In the window.
If detecting while running auto plus 3 is hiccuping on a spot swept, going to higher manual sensitivity may indeed allow the suspect area to give a more fuller tonal sound. This hiccuping I am referring to can be duplicated. By dropping a dime on clean ground. Keep sweeping and progresssively raising coil. Eventually you’ll hear the detector make this certain noise as dimeis swept. ID given on dime will get funky too. One of the possible tell tale signs of deeper (fringe) detectable targets- driven by detector sensitivty settings, other settings like fast recovery on, detect mode selected, ground mineralization levels, and coil size used.
Hope this helps.
Now remember in real high mineral soil, a lower manual sensitivty like 18 approx may be all that can be utilized. Could even be lower.
One last thing. Don’t fall into this trap. Just because you or a person finds things in a site, even good things like silver. This doesn’t necessarily mean you/they have detector setup the best or there are no other ways to set detector up to find more things. More masked and or deeper.
Oh yeah I fell into this trap. The reason I am mentioning this. Internet forums are great. Don’t get too much tunnel vision though.