Originally Posted by pcfriedrich
Never even heard of the name "SVS". Back when I bought my equipment (except my receiver, I ordered that from Amazon, after previous experience with Onkyo), You could go to stores, like Circuit City, and Sound Advice, that had listening rooms, and you could try everything out. I'm sure they still do, but not in every little podunk town. The internet has made it hard to buy quality components with confidence.
SVS is an Internet Direct company with a long and sterling pedigree. One can benefit by using an I.D. company in several ways. I.D. companies don't need stores to sell their wares, nor sales people to sell them under commissions. That allows these companies to sell superior products directly to you for less than many commercial companies could sell inferior products. Once you purchase an I.D. sub, that company allows a trial period (usually 30 days) to try out their product in your own home. That is the best way to audition anything. If you like it, then keep it. If you don't like it, they will issue you a return order and refund your money once you ship it back (usually takes a week or two for the refund). Most I.D. companies will not charge a shipping fee to your home, but will charge a shipping fee back to their factory. SVS allows free shipping both ways and a 45-day trial period. And the fact is, one can buy from I.D. companies with far more confidence than in most any commercial showroom.
A budget of $400 won't allow you to buy many subwoofers from I.D. companies. The reason is they build only high quality subs and not budget subs, which the Polk you mentioned certainly is. One of a few I.D. companies that has subs for under $400 is Hsu Research (the oldest of the I.D. companies and highly respected, but they charge for shipping). Up your budget to $500 and you will have a few more options, like SVS that basshead mentioned, along with Hsu and Reaction Audio.
Personally, I think you'd benefit from the sub basshead mentioned (PB-1000), or the Reaction Audio BPS-212 (dual opposing 12-inch drivers). While the consensus is that two good subs is better than one excellent sub is usually correct, I wouldn't call the Polk anything but a budget sub. And because you have a fairly large room, buy the best sub you can, then later when funds are available, you can buy a second.