Looking for a cheap sub...

You could get one as a kit in that price range but it would be a a passive model in that price range so you would have to drive it speaker level. The kits are very easy to put together,pretty much just have to install the drivers into the cabinet. The are very good bang for buck. It might be hard to find a good sub that would add much to your speakers if they are flat to 30 hz. for only $300. I looked in the for sale subs on Agon and found a few subs $300 and below but none I have listened to so I can't help you there.

FOr $300 there really is nothing out there that will add any significant extension to your existing system...I would wait till your budget increases...for a little more...you could go with a used Carver Jr...which has bass down to the low 20s..or even better...a used Rel...deep, clean bass doesnt come cheap...

I second Phasecorrect. If you can find a used REL anywhere close to your budget, I would jump on it.

Nothing is worse than a really crappy sub. I would hold out and get the HSU VFT-2. It really is a nice subwoofer, and will lighten the load on the rest of your system.

Your speakers are not flat to 30 regardless of what the specs say. I know "full range" 10k speakers that are not flat to 30. This sub won't be flat to 30, just a whole lot closer, while letting the receiver and speakers do what they can above 80. In the end your room probably won't allow for these flat responses.

You should be able to find a VFT-2 for very close $300. Anything over $350 is a joke for a used VTF-2.

Marty

I would also hold out for a used Hsu. Unlikely to find a used REL for under $500.