[rayson22]

have a quick question here, i took my e90 to an audio shop and let them installed my sub system ( 1 sub woofer 1200w, and amplifier 980w.) when they are done hooking everything up including the hi low switch, just noticed that even though the stereo is off i can still here the sub making that boom sound and even after i took the keys off the ignition it stayed on for about 5 mins. could there any possibilities that they hooked up to the wrong wires? any help will be greatly appreciated! do i need a capacitor to fix this?