No matter what head unit I hook my DD-1 to, it reads distortion before signal. I used it on my Kenwood DNX6180, I used it in my buddy's ride, and I used it on a radio that best buy had rigged up in their car stereo department. Each time, the DD-1's red distorion light would come on before the signal light would illuminate. I can even hook it to my Itouch and get the same readings. Yes, I changed the batteries. No, I didn't drop it, and it never got wet. It sits in a case on a shelf, indoors. I used it a month or 2 ago on my old set up, and it was tits. But now... not so much LOL