Nothing against those that choose to use a sub, to each their own. To me, it is over kill and not necessary. Most music contains nothing below say 40 hz...most speakers with say a 40 hz rating actually go significantly lower when interacting with the room. Lastly, you will never get the timbre to match the 2 channel speakers. To me, you are ruining the sound of a well designed 2 channel speaker.
Uh, @audioguy85, a statement like this indicates someone who’s never experienced a sub properly set up and hence is focusing on the wrong things. You have no idea what you’re talking about. Wilson Audio uses subs with their Alexandrias, which go gobs lower than your speakers could ever hope to. What do you think you know that they don’t? Ugh.