Hmmm, I'll qualify my comments up front by saying that I am not that well versed in HT. That said, it is true that there is a lot of information contained on the center channel. In HT and film reproduction for the home that information is in the form of dialog and panning information. Very little in the way of LF information is directed to the center in a typical home HT setup. A 5.1 or 7.1 system uses the LFE out, the .1, to direct LF information to the sub. If you want to experiment with two subs, my first choice would be to use a sub for each of the two front speakers, or try using a sub to augment the rear channel information.
2nd sub for center channel ?
A Tweeter salesman told me that if I wanted to have two subs to try the 2nd with the center channel if there is an OUT for it because there is so much info on the center.He said to then switch and put both on the sub out and decide which is best. First time I have heard that. Any comments ?