One or two subs?

[Feanor]

Hey guys I decided on adding a subwoofer to my bandw 602's. I have always heard two subwoofers placed symmetrically in a room are far superior to one subwoofer. While on a budget, my question is whether buying two inexpensive subwoofers and placing them symetrically will sound better than buying one more expensive subwoofer by itself. I know with two subs I can better integrate the subs seamlessly to my stereo configuration.

I once heard two subs recommended -- despite the fact that bass under 80Hz is non-directional -- because the two subs can reveal "out of phase" information. I don't know the veractiy of this theory.

I take "out of phase" in this context to mean sound recorded out of phase as between the left and right channels. Whether or not there is out-of-phase info would very much depend on the recording process and I doubt that it would be present in the majority of records. It would also depend on the usual sub considerations such as room placement.