When I say the word subwoofer, what comes to mind? Is it a giant box in the corner of the room that rumbles when the dinosaur pads along the ground onscreen? Or the thing that shakes the door panels of cars at traffic lights? Arguably, neither of those have very much to do with "music."
The category of music subwoofers, used for boosting the low-end performance of smaller bookshelf speakers, is still fairly unknown, though I can think of notable models from both Bowers & Wilkins and Bang & Olufsen. While Sonos doesn't technically make bookshelf speakers -- the Play:3 and Play:5 are more akin to speaker docks -- its products' bass response is still limited by the relatively small size of the cabinets. Sonos' solution: the wireless Sub.
Design and features
The Sub is designed to integrate into an existing Sonos setup, which is one of the most popular types of multiroom music system on the market. The Sub is a large subwoofer equivalent in size to a PC tower, with a distinctive O shape. At the center of the unit sit two oval, 6-inch drivers in a push-pull arrangement which setup Sonos says eliminates cabinet rattling. The cabinet is quite heavy at 36.3 lbs and is finished in a gloss black lacquer; it's quite a magnificent looking piece. The company is apparently planning a non-glossy version for later in the year (at $100 less), and I welcome this, as the black finish doesn't really match any of the other Sonos components. The Sub comes with rubber feet and can be placed upright or mounted on its side. Sonos even suggests putting it under the couch, a waste of that beautiful finish, though!
The Sub has only one control, a button that connects it to the rest of your system, and as a result there are no crossovers, phase switches, or other fiddly knobs to worry about; the software takes care of all that. Connections are similarly sparse, just an Ethernet port and Sonos' proprietary wireless system; there's no LFE input, so the Sub is only usable with a Sonos system.
Connecting the Sub to the system was easy. I simply called up the Sonos software, pressed the button, and was greeted by a couple of test tones so I could select when the sound was suitably loud for the room. That's it. You can connect the sub to any Sonos system (any but the Connect) with a built-in amp. The Sub is particularly handy for users of the Play systems since they don't offer a dedicated subwoofer out as the Connect: Amp does.
If you have multiple Sonos systems in your house, the software then gives you the option of which one you'd like to connect it to. It's a little fiddly to then assign it to another system with the software, but it can be done.