Actually. I was saying what he thought I was saying. I meant it, though, just as an experiment or as a temporary solution.

The only reason I can imagine he needs the relay (for his stated purposes) is because his alpine doesn't have an aux-in.

If the alpine's got an aux-in, then of course use it, and everything is taken care of, no relay needed. I'm sure he doesn't have that option or he would have done it that way from the beginning.