I had posted some numbers of the distances coins would give a signal on my Silver UMax.. The results were bothersome in that I dug several coins exceeding the original air test distances. This time I put the detector on a garbage can, with the speaker facing away from me..I put a board against the coil so That I could sweep the coins instead of just wiggle (as in the other test).and mark where the last "good" signal was DISC set at Iron, and sensitivity on max as I now hunt .Have some hearing problems, so the speaker facing the opposite direction has to be a good signal for me to hear it..I marked the distances , then measured when done..That way,just the spot distance,is given,," no helping"...Am calling a cent / silver dime in the 6 plus to 6 1/2 inch range...The clad quarter at 7 1/2 inches...Giving up 20 to 25 percent in the ground,,,and everything now fits..On all metal. you can get a slight increase..Since that is a "sand pit only" search mode, didn't add the extra half inch or so..Don't use earphones, so there is no way of knowing if the distance numbers would be jacked up any. I don't give a Rat's behind what anyone thinks or says, The Silver UMax is an exceptional value for the money..Will probably wind up with three detectors, a raw power ground pounder, and two Silver U's..Might even try a set of phones, except I hate those ear shattering blasts.Friend getting a Golden UMax.. Will be interesting to compare depth, and DOLLARS per INCH of DEPTH..I think we could do an interesting chart of all the detectors with $/inch..The super buys would stand out. Thanks for taking the time to read my ramblings, cordially NAD