When I first got my explorer I spent a long time on air testing coins and noticed that I liked Limits at 10 to start, giving me the widest possibility of the diff. denom. of coins in tones. Then by going to variability I tried them and the lower 6 seemed to be all to low of tones and then it started to seperate the lower from the higher tones at 7, then 8 and after 8 it got too high of tones for my ears and seemed to mix the penny,dime,quarters, silvers.....even though you wouldn't think so, but my ears do not like HIGH pitches....so I settled on 8 variability. Then I went to threahold tones and noticed by adjusting this I got diff. tones again,.....so by going thru all the 1-10 threshold tones I prefered 5.....all coins seemed to be distincful enough to tell the diff. between them and my ears where happy. These 3 settings always stay the same, so now I could concentrate on tones and train with it to get use to them and it came second nature. But I feel it is very important to go thru all the settings first before you should go out and hunt for the first time. That way you got the tones you like and the best seperation of coins in tones to YOUR ears.....and can tell between the tones what is what. Now its time to decide Ferous sounds or Condutive sounds and normal,audio1,2, or 3...normal for me cause audio 1,2 or 3 is just not my cup of tea.....By being in the field I tried both ferr. and cond. and didn't like the way(conductive sounds) iron made me have to look at screen cause it sounded high pitch....I like to walk and hear low grunts(ferrous sounds) as in iron and not have to look at screen till the higher tones come in. So that never changes either. Now the things that change are sens.,gain, coil sizes,deep or fast(even though I never use fast,I hate the fast clips of tones) sens: mainly is high as possible without any falsing, but then again every erea will dictate that setting...and if it is real iron infested or trashy I lower it so coil won't pick up 10 targets in close prox. this I find I can find the shallow stuff1-5 inches and sneek up on the coins in with the trash or nails. Coils size is usually small. so after using low sens. say 8-14, i can take it up a few notches and continue with the search. Some coils have the ability to see right thru the iron and see the high coins....like the Wot and the stock 10.5....it can get very frustrating but by being in All Metal, weather that be in Iron mask wide open or smart screen cleared...it gives you the chance to get the ones others walk right over. Gain use to stay at 7, but I found out late in the career that it can be adjusted to help you. I prefer to hear the diff. between deep and shallow so 7 gave me that ability. But when in a electrical noisey or hot rock places I found by lowering the gain to 6 and able to turn up sens a little more the falses where quiet but when coin got under coil the volume was enough to tell me it was a coin and not a false. Also I have always had Deep on and fast off for the longest time...but found out in a noisy place due to electrical noise if I turned off the deep the cursor settled down a bit and digital numbers steadied up better. So That can be adjusted from place to place...but when in good grounds I leave deep on and sens. high as possible and gain at 7....If there are really deep targets and little shallow stuff gain can be turned up to hear the deepies better....so its up to you to adjust when needed and never stay one way....you got to experiment on your own and don't just listen to the punch in these settings and your good to go. Not true. The first half of this is a must do to get the tones you want to hear...and leave them alone...and the second half is adjust to each area as it is presented to you. All readings you get on either cursor or digital #'s is not text book.....they can be altered by depth,ground minerals, moisture,more than one target under coil,condition of coin,position of coin in ground, etc.....so by digging an new area and not knowing what is there, dig the first 30 targets or so(just an example) you will have a good idea what to ignore and what to dig.....
Sorry this was just going to be a quick response but I rambled again.....I am sure I left a few important things out ....