i lost my post in a power outage. Did you ground the inverter? It seems as if when you run ungrounded power (i'm assuming your lapotp power plug has 2prongs, not 3) it creates a ground loop. If its not that, then i'm at a loss man. I wouldnt' give up still though:-).
here's an idea
Go on ebay
find a crossover that you like.
Bid to win.
They come with built in ground loop killers that you can set yourself. It will be a month before i set mine up, so try it and see. In the end, you'll gain a high quality crossover that will make your music sound better anyways. I'l sure other companies have somethign like it, but htis kills the groundloop before it gets to your speakers and they'll help you set it up if it doesn't do it right away. Hook it up between your head unit and your amps. That's it.
nope mic and line in are muted. that i checked in the begining as far as grounding how would be the proper way of going about it at this point im trying every thing