There really is no point to having iron audio on full time if you are using no discrimination.....you will hear the iron anyway , and really its just extra noise when using discrimination and it messes with the tones. Most of us aren't really concerned about knowing if there is any iron in the area , we are looking for coins , etc. If that's what you like then more power to ya , use what works for you , but the main purpose for iron audio is that you can turn it on now and then to check iffy targets for iron. I hunt trashy sites and rarely ever use iron audio , when iron is everywhere you cant tell if the target you are interested in is the source of the iron or if the iron is just right next to the target. If in doubt , dig anyway.