Subwoofer question

[bjwilli88]

Hey all,

I'm new to Home theaters and just have a question. I just bought a HTIB from amazon. Here is the link: http://www.amazon.com/Polk-Audio-HTS-9405-5-1-Channel-Receiver/dp/B001JEOQV0

It came with a Polk Audio PSW111 8" subwoofer. The bass is pretty good, it's just not quite cutting it for me, though.

My question is, would it be better to purchase an identical 8" sub, and use a y splitter to hook both of them to the receiver, or would it be better to purchase a 12" sub (like the PSW505) and use that one by itself? Or...could I purchase the 12" sub and use that one in conjunction with 8" I already have? Which option do you guys think is best?

Thanks!