It would seem that with this logic, a room full of tweeters should put out great bass.
You guys are taking things too literally.
Honestly, I would stay away from 8" "subwoofers" To me, those are larger midrange.
The point being made by the guy was that instead of one massive and powerful sub, 4 smaller subs (real subs) would give better and more even response in the room. A larger sub should go deeper, but if you are sitting in a peak or a null that can be very bad.
Ideal situation would be 4 larger subs like the 600s.
