Ok, I am kinda confused about something.  I have a Profile Clarus CL640 4 channel Amp bridged to 2 channels to power 2 Infinity Subwoofers.  My question is what spot do I put my patch cables into?  The speaker lines are marked but the patch cable spots are not.  It doesn't seem to be getting full power to the subs.  I have the cable coming from the sub spot out of the  headunit to Channel 1 & 3.  Would I have to add another patch cable for the 2nd sub?  I hope that rambling didn't confuse anyone but I appreciate the assistance you can give me.