A lot of people hear the word "sub-woofer," and they think that includes all of the bass impact we are hearing/feeling. When it comes to most mainstream music, however, it's actually the bass/mid-bass that probably turns us on, more so than the sub bass frequencies below say, 65hz.
How often do we hear reports of how surprisingly good the bass response is from some small bookshelf speaker with perhaps a 4-5" woofer, as if it's some sort of freak of nature? Then you look further into it and discover that the little speaker actually rolls off rather abruptly at 50 hz, or say, even 45 hz, giving benefit to doubt. Bass/mid-bass wins again.
Then onto the myriad of bass performance troubleshooting about the web, most all of which gets defaulted to the sub-woofer. 9 out of 10 times, the user would not be dissatisfied with the performance of his otherwise, well measured sub-woofer, but is actually missing the impact of solid, bass/mid bass performance from 100 hz to perhaps even 300 hz or so from the mains. How many people start researching "Mid-bass Modules," for being less than excited with what the sub-woofer actually does?
So do you need a sub-woofer? I don't, but then, what I typically listen to doesn't have much to offer below 40 hz and my rooms are rather small by today's standards. I also notice that the music I listen to tends to naturally roll off right about when my speakers do. It's almost as if the engineer who recorded my music must've also had speakers similar in performance to mine. I do own 5 sub-woofers (6, if I count the one in my truck) though and I can get great performance with them with most of my smaller speakers. With my larger main speakers that have 12-15" woofers, it kind of ends up being the long way around the block for what audible, musical qualities they may add. I've been hooked on the bass that the Eminence Delta Pro 12a's do in my main speakers, is the only reason I am not using subs, or end up crossing the subs really low, instead.
