make sure the ground on your trans is clean then
reason why i say no: if your power wire is to the batt then the wire to the fuse box has no more load then with out a system
also when you crank it are you sure its not the box peaking out? cap = extra weight lol
OP: what HU you have? model and everything
also make everything flat no boost at all
your gain should be set to the voltage that the HU is feeding the rcas
just becouse its wired to 2ohm dose not mean its seeing 2 ohm your gotta take in effect rise IE: my Aqs where wired down to 1 ohm but when mettered showed 2.66 on 1 amp keep in mind that was a test tone music the ohm load will change alot depending on the note and how the sub and box react to that freq.
