Originally Posted by billmoon73
I have an '04 Baja Turbo with the 'upgraded' factory stereo (in dash 6 disc changer plus the tweeters). When I fade to the rear speakers there is a clear and noticable DECREASE in low end response, greater than would be expected from just a 'weaker' speaker unable to produce lower end bass.
Do you have the factory subwoofer underneath one of the front seats? If so, put your ear close to that and see if its volume goes down when you fade from front to rear speakers. You can also unplug the sub and see if this phenomenon stops.
All of the factory subwoofer harnesses that I've seen have tied the sub to the rear speaker outputs, so more rear = more subwoofer. But one person claimed his sub was running off the fronts. Perhaps that's the case in certain models? It's tough to know because the powered subwoofer harness does not appear on Subaru's schematics for the various vehicles.