Originally Posted by Spud2388
Bump. I think I have found the answer after a little more digging. The 3.0 does send out a full signal to all the speakers but the dash speaker has a crossover attached to it to cut the low frequencies. Still am unsure about the 8.4an. I know the ones set up for the Alpine system have the crossed over signals and the ones for the base speakers do not (same signals as the base 3.0). But am unsure on how to tell which is which. I guess you vin would tell it which signal to send out, either use the internal amp for the 6 speaker system or send the digital signal out for the Alpine system (the amp processes the digital signal and turns it into high level speaker voltage. That's from what I have read anyways.
The 8.4 alpine HU unit sends full freq to the amp. The amp has the crossover built in.