Got my Hifonics HFI100.4 in today

[SloFiddy]

So i got around to installing my mids amp today and i can't seem to get the rca's right. If im understanding correctly, running a single set of rca's into the 1/2 rca slot and switching the amp to mode '4' it should copy signals from 1/2 to 3/4 correct? At first i was having some serious distortion/echoing issues. I re-ran the rca's and it helped, a lot. But now I'm having troubles with front/rear sound differences. Both filters are set to full range and gains are identical. But the front seems to produce more treble, where as the rears, more bass.

Aside from that i am very happy with the amp, minus the problem at hand. Which i'm sure is user error.

Any input would be awesome!