2005 Corolla Install Question

[kyles]

Ahoy-ah-hoy. I posted this in a corolla forum and got very little useful response, so I thoguht I would try this forum out since the primary subject is audio-related.

I currently have a 2005 Corolla CE, 5sp (Phantom Grey if that matters to some of you) and have done some work on the stereo components…as listed below.

Head deck- Stock Toyota
Line-Out Converter: Peripheral SVEN4 4 channel, variable output
Amplifier: MTX MXA4004, 4 Channel, 50 watts/channel RMS @4 ohms
Rear Speakers: MTX TDX6903, 6” x 9”, 3-way, rated at 100 watts RMS
Front Speakers: MTX TDX6502, 6-1/2” (6-3/4”), 2-way, rated at 60 watts RMS

(See Attached Iamges or rear area install from trunk)

Here is my problem. I have taken a lot of time and effort to ensure that the rear speakers have been properly sealed from the deck side of the mount as well as the top “gasket” mount area with foam and silicone (to keep the front and rear sounds from cancelling each other out). The speakers pound pretty well, but I loose bass response when the fronts are turned up, or gained on the amp for that matter.
To remedy this, I have made one of the front speakers 180 degrees out of phase (ie. switched the pos./neg. outputs from the amp) and turned on the cross-over at around 80 Hz which has helped in bass response on the front end. But the rears still seem to die out at low frequencies, almost to the point where the front speakers with the cross over on are achieving better bass. What can be causing this? Is this possible that the trunk volume is too large for the 6x9’s to work with? Or am I kidding myself and need to get a proper deck installed?
Would appreciate any feedback you may have with this silly problem.
Many thanks.