I am currently upgrading my passive 100 watt subwoofer I got in an awesome $50 deal i got on craiglist for a HT-330 onkyo surround sound system (can be seen here) with a powered subwoofer. I was wondering if is possible to hook up my subs in series so that I could potentially use my old subwoofer and new one instead of just throwing the other old one out. The new subwoofer is a Polk Audio PSW Series PSW10 10" Powered Subwoofer while the old one is an 8 inch passive type that uses standard speaker wire. This setup is for a small dorm/bedroom and I am pretty poor/cheap at the moment to be honest. The receiver provides 8 ohms and 100 watts/channel (although it is more like 60 watts/channel to be honest) Is this worth it and safe to do? Again, I am a poor college student so just having powerful yet poor quality bass is not too big of an issue for me. Thanks for any input!