You might just be looking at some of the Alexa-powered devices due to show at Amazon's rumored hardware event this month. Pocket-lint has spotted listings (since pulled) for the Echo Sub wireless subwoofer (above) and Smart Plug (below), both of which see Amazon venturing into unfamiliar territory. The Sub adds 100W of bass to an Echo or Echo Plus setup, whether it's one speaker or two -- yes, stereo pairing would also be new. It reportedly cost £75 (about $99) when it shipped on October 11th, which might be a small price to pay if your rap or trance isn't sufficiently room-shaking.