Our Verdict 
It takes up a bit of space, but thanks to its bold and powerful performance this KEF surround package deserves every inch
For 
Bold, powerful presentation
Seamless integration
Fine timing and dynamic range
Incorporates two pairs of Award-winning stereo speakers
Against 
Centre speaker lacks some expression at lower volumes
Physical bulk won’t suit everybody’s environment
Reviewed on

To paraphrase one of Morrissey’s more inspired lyrics, we have indeed just discovered that some speaker packages are bigger than others.

It is these speakers’ sonic ability that warrants a five-star rating, of course, but there's no ignoring the KEF Q350 5.1 package’s brutish stature or the physical command its has over our listening room. It’s certainly not one for a small bedsit.

Build and features

The package takes its name from the Award-winning Q350 standmount speakers, two pairs of which comprise the front and surround channels. These are joined by the Q650c centre speaker and a brand-new Kube 10b subwoofer.

Both the Q350 and Q650c are fitted with the latest generation of KEF’s iconic Uni-Q driver. What looks like a single driver is actually a 25mm vented aluminium dome tweeter sitting in the throat of a 16.5cm aluminium mid/bass driver.

The single point-source arrangement is designed to improve integration between the drivers and improve the way sound is dispersed, with the distinctive waveguide on the tweeter helping distribute sound evenly.

MORE: KEF Q350 review

The latest evolution of the Uni-Q driver features a damped tweeter loading tube – derived from KEF’s high end Reference series – to soak up unwanted activity from the back of the dome.

It’s designed to improve the quality of the high frequencies. Other tweaks have been made to the motor system and shape of the mid/bass cone to help reduce distortion.

The Uni-Q driver sits right in the middle of the Q350’s otherwise largely unadorned cabinet – not only to keep a consistent look with the rest of the company’s speaker range, but also to help control internal standing waves and improve clarity – and on the Q650c is flanked by a pair of equally sized low-frequency drivers.

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The Q350s also benefit from reflex ports that have been positioned to the back of the speaker, which KEF claims ensures any midrange leakage of noise is less audible.

Said ports have also been redesigned to reduce noise and distortion for deeper, cleaner bass performance.

We’ve mentioned these speakers’ physical heft – each Q350 measures around 36cm tall and the Q650c is 63cm wide. With positioning a priority, you’ll need a fair-sized room to accommodate each with a little space free from surrounding walls.

Bulk is one thing, but there can be no qualms about the quality of their build.

Available in either black or white satin finish, they feel as sturdy as they look smart, possessing a sleekness that belies their physical dimensions.

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More after the break

Though there is nothing lightweight about its counterparts, providing the real low-end heft is a new addition to KEF’s range of Kube subwoofers, the 10b.

It features a DSP preamp and a not-inconsequential 300W Class D amplifier powering a front-firing driver – in this case measuring 25cm in diameter. 20cm and 30cm models are also available.

By the prevailing standards of subwoofers, and indeed the rest of this package, the Kube 10b is quite lean - there is minimal extra volume beyond that the size of its driver necessitates.

It matches the Q350s and Q650c in its subtle, minimalist design. Handily, to its rear you’ll also find the Kube 10b benefits from a manual volume dial and variable low pass filter ranging from 40Hz to 140Hz.

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Sound

Once steadily positioned upon its stands, we begin by hooking the KEF Q350 system up to our Award-winning Denon AVR-X6400H AV amplifier and spinning a Blu-ray of the Miles Davis’s biopic Miles Ahead.

Having had a weekend running in, these speakers have little trouble blistering through the trigger-happy car chase of the opening scenes - they use every ounce of their muscle to pin us back into the sofa.

But there’s organisation within the chaos. You’d expect little else, but superlative integration between the two pairs of Q350s - and  conjunction with the Q650c - means they don’t disappoint.

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Rather than noticing the sounds emitted by each speaker, regardless of how well they interact, there is simply that immersive unity for which all 5.1 packages strive. We're able to forget just how many speakers are on the job.

That’s aided by a robust but agile performance from the Kube 10b subwoofer, which punches more than booms and serves up sufficient rumble in our guts without hamming any of its lines. The Kube certainly has quick feet for a big man.

But such frenzied scenes are rare in this particular picture, which largely acts as a barometer for the KEFs’ handling of dialogue - and its musicality. Unsurprisingly for a package including two pairs of Award-winning stereo speakers, music is delivered with aplomb.

Through our Denon AV amp, a secure sense of rhythm and dynamic range is evident, unmuddied by the extra bass provided by the sub and Q650c’s low-frequency drivers.

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Dialogue is largely the domain of the centre speaker, and at reasonably high volume it doesn’t disappoint. There is plenty of body, and the Q650c is able to match the Q350s in terms of its level of expression.

Our only qualm is that a fair amount of that talent is veiled at lower volumes. All speakers have a level at which they open up and give the best account of themselves, and for the Q650c in particular – though we also mentioned it in our original Q350 review – that volume is reasonably high.

That shouldn’t dissuade many home cinema enthusiasts, but it's another reason to place these speakers in a room of decent size, where finding the KEFs’ sweet spot need not be an assault on the ears nor irk too many neighbours.

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Verdict

There’s no denying KEF has done a remarkable job here. Building a championship-contending team is by no means as simple as merely cloning your star performer and throwing in a couple of well-drilled journeymen.

Even considering the Q350’s talents are already well known to us, the fact that each component plays its own part earns this system its five stars.

If you have the space to let your 5.1 package stretch its legs, then you should consider opening your home to this outstanding KEF package. For its combination of power spiced with precision, you could do much worse.

Read all our KEF reviews

Breakdown 
Sound
Compatibility
Build