Gila, how ya doin? This is the voice of guilt here, Marc Trainor. I'm so busy, and need to work tons of hours, I can't get with you quite yet, but that's another post, privatlly. Ok, I'm going nuts on this audio thing, but I pulled Andy's book out and I'd turn to page 46 and 47. This deal's getting pretty tricky here, so I'll take it slow and solomenly, but here's what it sounds like to me. On the Quatro, the "numeric" reading is always based on the ferrous versus conductivity rating: in onther words, if your looking at a nail or an old piece of iron it's gonna be in the negative number range, (-10 to -1) If it's a piece of tin foil, pull tab, copper, silver, it's gonna be in the 0 to 40 (positive number range). That's it for the numberic reading portion. Where it get's confusing to me and pretty tricky is the audio portion. On page 46 you'll see where the Explorer has two different "visual" settings, ferrous and conductive, where as the Quatro only has one visual setting. Notice that a wheat penny on the Explorer "visual" reading has 27 as conductive and 5 as ferrous. Now look at the same "Explorer" reading for a screw cap. The conductive reading is still 27 but the "ferrous reading" is 08, a higher reading than the 05 for the ferrous reading on the wheatback. Apparently, what we're seeing here is even though the wheatback would read at around 34 on a Quatro, and 27 on an Explorer, there must be some kind of "ferrous content" in both the wheatback and the screw cap in order for the Explorer to decern the differens in the "ferrous content". That's where I'm wondering what's going on here, but, all I know is what I'm seeing here and there's sure a difference in the "ferrous reading of the two different targets". Ok, with all that said, jump over to page 47 in the book and notice that even on the Explorer the two different targets here would have the same conductivity reading but different ferrous readiings. According to Andy, on the Quatro, when the audio is set at conductivity, there wouldn't be any noticible difference, but when you set the audio to the ferrous mode the screw cap would be lower tone than the wheatback. In other words, since the difference couldn't be seen on the visual screen because the Quatro only has one visual reference, you have to go to the audio to see the difference, meaning that the ferrous audio would show the difference. Whewwwwww. I hope I'm right on that, because that, to me is the whole crux of this audio cross saving thing and the main reason why we might use it. According to Andy, some ferrous targets can become conductive and give a high audio reading, but when you look at the visual reading it confirms that yes, it's truly a ferrous item wiht a low minus numeric reading. on the other hand, look on page 42. If your trying to read a dime, a quarter an indian head and a bullett in conductive audio, you won't hear any differnce but once you change over or "cross over" to the ferrious audio, you can hear the difference between those different targets. Also once you cross save from one mode to the other, you also need to go back and check on which numbers you want to be discriminated. At that point you can just "re-adjust" the discrimination "numbers" to suit your needs, In other words, first do the cross save for the audio preferences, then re-adjust the discrimination settings. Hope I'm right on all that, and hope it helps. Marc Trainor.