I got news for you...the vast majority standard passive home monitors can handle full range DD/DTS soundtracks properly without distorting, bottoming out, mushing out, etc! You should be crossing that speaker, over at least 80 hz, or 50-65hz if you have a pre/pro with base management!
Really, for proper results you should be crossing your main 801's over at around 50-65 hz as well!..and letting a POWERED ACTIVE sub or two handle the rest!
You'll alway's get a relatively week and stressed sounding system otherwise. Even though your mains are full range speakers, they're not designed to handle a full range Digital soundtrack. They're music speakers.
This is the very reason companies made ADVANCED BASS MANAGEMENT!...with flexible cuttoff frequencies from 30hz up to 160 hz! Actually, most pre/pro's only do 80hz or full range, and neither is really practical. 50-65 hz is best usually.
Outlaw audio has the piece you need to put between your pre/pro and the amps. It's called the ICBM, and it's fantastic!
You should, in my experiences of 1000' of installations, be using some sort of better bass mgmnt with the speakers you have...you'll get infinitely better results with your HT!..I promise
You could use your 801's, use the matching center for the matrix series, use the ICBM at $250(cheap!!...and pretty transparent really!), cross your mains over at 50=65hz, and the center the same, and let the sub do the rest! Man it will sound so strong you won't believe it!
Oh, and 2 center speakers is going to cause some problems really. Actually you could put two of the 805's on either side of your monitor, but I wouldn't put em together(you'll get all kinds of phase problems otherwise.
Good luck