Re: Small, cheap and used powered Sub?
Awesome choice. I have two F12's and love them. I have them on SVS SoundPath isolation feet and my duplex neighbors have never complained, FWIW. Make sure you keep the rumble filter on and they won't make any of those crazy rumbly noises that other subs make. The servo design keeps them from wasting energy on shaking the enclosure around so that should make your neighbors much less likely to notice it. Keep the volume down, though, because it can really dig deep.
-Alex
PS4/Nvidia Shield --> Emotiva XMC-1 --> Emotiva XPA-5 --> Ascend Acoustics Sierra Towers and Horizon Center w/ RAAL tweeters (L/C/R), HTM-200 SE (Surrounds), 2x Rythmik F12 subwoofers