So, I gutted my cavalier for the subs, amps, head unit and wires the other day. After a very long process of trying to get the subwoofer enclosure to fit in the trunk (12"H 36"L), pulling up the carpet to get the power wires and RCAs run and trying to scrounge enough 4 gauge to go from the battery to the trunk, it's finally installed......and sounds like crap.

I'm using a Pioneer DEH P880PRS as a HU. I love this thing. It has a dual 16 band digital EQ with an auto EQ option and Time alignment plus three way networking to get the highs, mids and lows dialed in just right. From there I've got 4" 42.9i Kappas on all four corners. the in-line crossovers these use really let you adjust the frequencies to the 'T'. Then I've a 10" sub on a 300 Watt Pioneer amp to the rear RCA outs and another 2 10" subs on a 760 Watt Pioneer amp to the sub RCA outs. All three subs are in a 12"x36"x tappered 13" box that pretty much takes up the entire "top" shelf of the trunk behind the seats. Same set up I had in the cavalier that sound awesome.

I think the problem is a combination of things. First, the subs are old MTX Blue Thunders that back in the day were the cat's pajamas.....unfortunately, that day was about 10 years ago. They're wearing out. They don't perform well in the cold weather up here which leads to my second problem. The trunk does not warm up. There's a 1/4" piece of fiberboard over the substantial amount of metal bracing behind the seat back cushion insulating the trunk from the cab. Which is the crux of the third problem....that's a lot of material for 3 old *** subs to make noise through. I think the box is too big too. Pointing backwards, there's no where for the bass to really go because the box fills up that whole void....

sigh....This just wasn't an issue with the wagon.....back to the drawing board I guess.

 

well...I putzed around with this a little more last night. Turns out you really don't need the high pass filter dialed up on these Kappas. The built in crossover mechanism does it for the HU. After turning both the rear and front HPFs off and re-adjusting the EQ to compensate, I'm getting closer to what I know this system can sound like.

consequently, I'd like to hear what any of you other 240 sedan/coupe owner might have done differently with the sub box. Did any of you remove the fiber board behind the rear seat back? Maybe leave the armrest down?