I'm assuming your HU runs on 4 Ohms here. If your speakers are say 1 or 2 Ohms, once you turn it up, your stereo gets overworks, can't match the Ohms, and the speakers will shut off. This happened to me when I had my Bose still hooked up for a couple days without the amps on my Alpine. If you have aftermarket speakers, I'd say it has to do with the way you have it wired up. Hope that helped any