Deep, punchy bass from a shallow, wall-mountable sub
Focal's Sub Air powered subwoofer stands out from the pack in a couple of cool ways. For one, it's shallow enough to literally mount on the wall — no need to sacrifice an inch of floor space. Focal even includes the mounting hardware you need to install it.
Second, it's wireless, which opens up even more placement possibilities. Hook up the included transmitter to your receiver's subwoofer output, and place the sub anywhere within a 49-foot range. (Just remember: you will need to connect the subwoofer and the transmitter to AC power.)