If the overall sound level is lower than you prefer, set all speakers to "LARGE". If there is not enough bass, you should be able to use the internal setup to boost the bass levels??
Actually, I have my mains & CC set to "LARGE", this disables me from even setting a crossover level. My surrounds are set to small and Xover set to 80 Hz, and my LFE HIGH CUT>STD(120 Hz). I guess preamps are different than receivers because you can still set the crossover even when set to large as you have stated.
Joel, since bass sounds have a certain amount of directionality, it is best not to cut them, if possible. See if you can disable the Xover to your mains? Let them babies RIP!!! That's not "rest in peace", that's rock and roll.
One more test, instead of disconnecting the center, set it to "NO". The sound of the center channel should be output from the front speakers.
Oh, according my Sony manual, when you set your CC to "SMALL" to activate the bass redirection circutry, those bass frequencies are going to the subwoofer if you are using Dolby Pro Logic set at Normal. Still doesn't explain why the fronts are not getting bass.
Stay at it...We're all in this together>>>