I have to disagree regarding the frequency and localization issue. I propose that if you believe that you cannot 'localize' a sub that is cutoff below 50 Hz, then try this.
Put the sub, LPF set at 50 Hz, at the 1/4 point between the speakers. That is, halfway between one speaker and the midpoint between both speakers. I guarantee you'll be able to tell which side it's on, provided that your speakers are set up properly, and in a room that's a decent size. The effect gets more noticeable, naturally, as you move the sub closer to one speaker. And when you've proven to yourself that you can 'localize' it, the case for two subs over one is practically irrefutable.
I was a non-believer before I tried this myself, having subscribed to the common knowledge. Sorry, but this myth needs to be debunked for the good of the audiophile community.
Put the sub, LPF set at 50 Hz, at the 1/4 point between the speakers. That is, halfway between one speaker and the midpoint between both speakers. I guarantee you'll be able to tell which side it's on, provided that your speakers are set up properly, and in a room that's a decent size. The effect gets more noticeable, naturally, as you move the sub closer to one speaker. And when you've proven to yourself that you can 'localize' it, the case for two subs over one is practically irrefutable.
I was a non-believer before I tried this myself, having subscribed to the common knowledge. Sorry, but this myth needs to be debunked for the good of the audiophile community.