Adding to the comment above....
Part of the review by an amazon user :
"Some have inquired about the subwoofer which is passive (not self powered) and also about active subwoofers. The passive subwoofer supplied with the 3300 is, in my opinion, plenty strong. I did a bit more research into this and there appears to be a 50/50 split. I reviewed opinions etc., and weeding out the comments that try to be expert but only provide one line responses it appears that there are pluses and minuses for each. Again, it is subjective and boils down to your personal preference. I also called Onkyo tech support to inquire about future upgrades for the 3300 and the pleasant gentleman responded that if I wanted to upgrade the subwoofer I would probably need to purchase a new system. I am ok with that because he also reminded me this an entry level system. Entry level or not, the 3300 is plenty powerful for my needs but please share your comments to help others decide on possibly the 3300, 5300 or other type system. Try not to get too caught up in the ongoing, neverending debate. Go with what you like...not matter what your ears will love you for it. ":clapping:
Heres the link for his entire take:
Amazon.com: Sketch "Supremesketch"'s review of Onkyo HT-S3300 5.1-Channel Home Theater Re...
And morover i have even heard some people on this forum pointing out that the 3300's passive sub outperforms some yamaha active sub
. As you have mentioned a 12 ft viewing distance the passive sub will be more than enough, that is unless ur a bass freak and you dont have unfriendly neighbours. TC Cheers!!