I'm installing an OEM subwoofer in my wife's 05 Legacy. I note that the OEM subwoofer has two configurable settings on it. One is the crossover, and I think(?) the other said "gain." (The car is not here just now, so I can't check the wording). Does anyone have any suggestions for how far I should turn these up as initial settings? (I.e., the settings most likely to please the average listener)?