I gave a follow-up on my review below the original post with a happy ending. I had issues with the Automatic ADEL modules that came stock with my A12s (as you'll read below), but I'm going to keep the original post in case new customers get their IEMs in the mail and have the same issue my ears did. You will be able to read my frustration, possibly relate if your ears are like mine and are hearing all kinds of noises in various settings and don't know what to make of it...