KEF Q400 Subwoofer Review (Updated 2023)

A Lesson In Performance

**Unfortunately the Q400 has been discontinued but we've kept the original review below. If you're currently in the market for a sub, the KEF KUBE 12b is one of the most highly rated substitutes**

KEF Q400 (Original Review)

What We Like

What We Don’t Like

KEF produces an array of high-end audio devices. However, that isn’t be apparent when first glancing on the Q400. Low specs in the context of other speakers make the subwoofer look unattractive. Make no mistake though, this is one of the best subwoofers under $1000.


Spec sheets aside, this subwoofer is gorgeous. The speaker comes in flat black, white, and two wood grained finishes. Despite your choice in finish, a trend runs through all of these options. The front panel is cleanly finished, beveled at the corners to add depth to the front. Finishing it off is a clean, but well-placed, 10-inch woofer sitting dead center. Other than that, there isn’t much else. Of course, the usual assortment of hookups are around the back, with no porting in sight.

For me, the look of the Q400 is stunning. The understated yet bold design sticks out in all of the right ways. No theatrics, just solid design. There’s a small footprint taken up by the subwoofer, allowing it to fit in most rooms will little fuss. Additionally, the different finishes allow you to find the one that fits in your set up perfect. I would give you my personal favorite, but I can’t design because they all look so good.


All the essential show up, including volume, phase reversal, tunable crosser (ranging from 40Hz-140Hz), and automatic signal sensing. The most interesting feature is the bass boost switch, though. Interesting, because it doesn’t show up on all subwoofers, but no special. No, the switch just adds a soft bell boost of either 6db or 12db at 40Hz. The woofer measures 10 inch across, housed in a die-cast aluminium chassis. That means it helps reduce all that resonance you don’t want.

The feature set of the Q400 come up short. Yes, controls are here to tune the subwoofer for your set, but it’s not enough. It should be expected at this price point that more features than a bass boost show up outside of what comes stock on high-end options. I do like what is here, but it’s disappointing that KEF didn’t add a few options for tuning the speaker considering a bass boost is already present.


I said this was one of the best subwoofers under $1000, and I’ll stand by that statement. Performance always wins, and the Q400 doesn’t slouch. The woofer’s cone is designed in the same way as the UniQ array from KEF. In translation, this woofer is powerful and tight. A 50mm voice coil handles the 200W of power effectively for low-distortion and full impact.

The Q400, while impressive on paper, sounds incredible. It won’t blow away everything else in your system or bombard you with low-end. That isn’t the point, though. KEF has instead focused on making a subwoofer that performs well in the setting where most people will use it – at home.