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KEF X300A powered loudspeaker review

  • Bubbles. Let us begin by popping some: KEF’s X300A (AU$1000/pair) aren’t a powered LS50 (AU$2000/pair). They might present with a similar Uni-Q point-source configuration, trickled down from the Blades, but if you think you’re getting the LS50, amplified, DAC-d, for half the bigger brother’s RRP, think again. In the X300A we find the same coaxial driver array as per the Q100 passive monitor (AU$750/pair).

    The X300A aren’t just loudspeakers either. They’re a complete hifi system. Everything in one box: DAC, amplifier and transducers.

    There’s no DSD compatibility on offer here. You can’t even play PCM files above 24bit/96kHz. Let’s not forget that hi-res (and especially DSD) are audiophile niches within audiophile niches. Their seams are narrow and shallow – not every consumer cares about bit-perfect playback or jitter. This isn’t a set-up for bleeding-edge tweakers. It’s a system-in-a-box for pragmatists and/or newcomers. Say it again: pragmatists and newcomers.


    There are two amps inside each speaker – one each for woofer (50w) and tweeter (20w). Typical of KEF’s ‘no compromise’ mandate for the X300A they didn’t go with Class D here – inside are twin Class A/B amplifiers, developed in-house by KEF’s mothership GP Industries. In housing its own amplification each loudspeaker needs its own power feed.

    Inputs. There are two. USB (mini-A) and analogue (3.5mm socket) are found on the rear panel of the left loudspeaker. There’s no S/PDIF so anyone looking to hook in an Airport Express, Apple TV or Logitech Squeezebox should shop elsewhere. No word (yet) on whether the Squeezebox Touch + EDO can play ball. I deployed a MacMini as source; it keeps the digital audio ‘always on’ and thus defeats KEF’s 25-min auto-shut off. Removing the possibility of missing the first few notes of music when bringing the X300A out of standby is a good thing.

    Another sign of KEF’s dev team smarts: a USB cable joins the loudspeakers digitally. The incoming USB signal is processed by a DSP before being sent to the internal DAC – a PCM1754 – in each speaker. This holds true for the analogue input; a WM8782 ADC digitizes the incoming signal. Consequently, there’s little point in bringing your own fancy-schmancy DAC to this party. The analogue input was most likely included to keep iPodders happy but the side-benefit is that it keeps turntablists in the game. One could imagine the simplicity of the X300A and a Pro-ject Debut Carbon (plus phono stage) being a stellar pairing. One more factoid: the USB connection takes precedence over the analogue input.


    With all this technology inside each loudspeaker, it’s no surprise they weigh in at a hefty – 7.5kg each.

    Whenever I see active ‘computer’ speakers the apartment dwelling synapses in my brain fire. KEF might want you to ‘hifi your computer’ – on the desktop – but I was eager to see how they sounded in free space, on stands as a main rig.  I’d been curious about this from the moment I first clapped eyes on the X300A at 2012’s RMAF. Would it satisfy as a lounge room system? Unboxing the X300A nine months later it became abundantly apparent that KEF had thought of this too.

    A switchable EQ can be found on the rear of the left box: it’s intended to maximize imaging depending whether the X300As are on ‘desk’ or ‘stand’. Such flexibility is not just a boon, it shows that KEF has thought about what consumers want from their hi-fi, particularly those new to the whacky world of audiophillia.

    Talking of which – port bungs are supplied. Each bung separates into inner and outer sections so that a half-bunged port is possible; you’ll need both in place for placement close to a rear wall or both out with them stood in plenty of free space. I positioned my review pair somewhere in between so went with the outer-bung only.


    Listening. The X300A sound is full-bodied and thick-blooded which makes for a kinder handling of thinner, bleached recordings (than the recently reviewed Zu Soul MKII). I’d not enjoyed Kitchens Of Distinction’s The Death Of Cool so much in years! A wine analogy here: the sound moves from a thinner Merlot to a more solid Cabernet Shiraz after an hour’s warm-up.

    The Uni-Q driver arrangement allows for sound staging that’s better than average. The X300A are strong on layer separation and deconstructing complexity. Take James Holden’s Renata EP. The KEFs make it a cinch for one’s listening focus to remain anchored to the rear-centred rhythmic bass charge whilst tracking the midrange-dominant synth whirls that swing from left to right and back to front. Neither crowds the other out. It’s the same with Bob Dylan’s Love And Theft; his vocal rasp might be the most upfront part of the mix but it doesn’t obscure the dynamic interplay between bass, drum and lead guitar; each of which remain richly coloured against the back-dropped spirit of the X300A’s cooler neutrality.

    I can picture the most anally retentive of audiophiles taking issue with the sometime exuberant highs, particularly when driven hard.  You won’t witness the refinement of a ProAC TR8, Spendor SA1, ATC SCM 11 or even KEF’s own LS50 but in the context of the asking price it’s a non-issue. Besides, hearing AtomTM‘s “Pop HD” layers deconstructed so cleanly is what makes these powered KEFs so enjoyable with electronic music. You probably wouldn’t get such clean definition from warmer boxes.  Many would struggle to achieve such dynamic flair from combining their own separates.


    I’ve consistently championed Usher’s S-520 (~AU$350) as being the goto standmount loudspeaker for less than four hundred bucks. I’ve yet to witness those same Ushers offer as much transparency or midrange presence as the KEF X300A. The S-520 demand power and power costs money. Even the superb Brio-R from Rega would tip your spend well beyond the X300A’s sticker, after which you’d still need to source a DAC, interconnects and speaker cables.

    Despite the analogue volume control being located on the rear of the X300A’s left speaker, I set a rough maximum and used a remote-controlled Audirvana+ to move volume downwards. Detractors of digital volume attenuation need not suffer anxious wheezing. With a 24-bit DAC handling 16-bit source files I never had to worry about data sacrifices. 1 bit = 6db and 48db is a long way down and Audirvana+’s dithering presented no audible artifacts or colouration. Besides, the X300A isn’t really intended for those worried about such things. Remember the newcomers and the pragmatists?

    Pragmatism. If you think such active monitors have no place in an audiophile’s life, think again. My buddy Andreas is an audiophile who doesn’t own a hi-fi. Why? Because he can’t resist the urge to upgrade or tweak. He just can’t help himself (poor fella) so he owns nothing because he can’t afford everything. A sensible move of self-enforced restraint. The KEF X300A would be a perfect fit for his life; there’s nothing here to upgrade (unless you count the USB cables or power chords, 99th percentile concerns both). You can’t upgrade the amplifiers. The DAC is staying as is. There aren’t even any interconnects or speaker cables to play with. This is a complete, audiophile quality system that’s ready to up ‘n go – but go no further.

    By keeping their first foray in digital audio a ‘no compromise’ affair, KEF has freed us from the tyranny of choice. Their X300A is a set menu system – entree, main and dessert – and it is truly delicious. An everyman hi-fi product if ever there was one. Brav-bloody-o. DAR-KO award.


    Associated Equipment



    Audition Music

    • AtomTM – HD (2013)
    • James Holden – Renata EP (2013)
    • Bob Dylan – Love And Theft (2001)
    • The Kitchens Of Distinction – The Death Of Cool (1992)


    Further Information

    John H. Darko

    Written by John H. Darko

    John is the editor of Darko.Audio, from whose ad revenues he derives an income. He is an occasional contributor to 6moons but has previously written pieces for TONEAudio, AudioStream and Stereophile. John used to live in Sydney. Now he lives in Berlin.

    Follow John on YouTube or Twitter


    1. As you’ve said, John, that is an all-in-one hi-fi system for people who either are on a tight budget or believe in a no-nonsense approach to listening to their music. I think it’s a high time for audio equipment manufacturers to realize that there is much bigger market for them to explore in that category than any high-end niche market. I applaud those manufacturers who are already in the game…

      The only missing element that would make the KEF’s system closer to perfection, is a wireless connectivity. Dynaudio makes the excellent XEO-3 wireless powered “desktop” speakers (Wi-Fi, as opposed to Bluetooth), which do not include wired connectivity. They also sound great away from the desktop.

      I wonder which approach is better from the practical, as well as from the sound quality, point of view. Probably, combining wired and wireless systems into one would be a totall perfection…

      Anyway, until such a hybrid system emerges, is there a chance, that you might want to compare these two approaches and give us your opinion?

    2. (1) That last comment is very timely. I’m looking at these KEF X300A powered speakers versus the KEF LS50 with a small class-D amp (like a Bel Canto). Hope to read your review of the LS50 soon.

      (2) What bookshelf speaker stands are you using?

    3. This is the best review of these speakers I have read, if only because I too got caught up in that expensive cycle of upgrading various parts of my system. So I got off my a**e (something more bloggers should do) and auditioned the X300A’s against the LS50s and was blown away by their sound quality, simplicity and price. Should I feel the dreaded urge to upgrade in the future I can just wait for KEF to build a better model. Keep up the good work Darko!Pip Pip.

    4. Good stuff John, but the logical competition for the X300 – IMO – is Dynaudio’s 2.5K Xeo 3. Considerably more expensive, granted, but those who dont want to spend that kind of money can hook their TV/BD player up to the Focal Bird 2.1 for roughly the same money as the X300. Either would make for an interesting comparison, but I look forward to the LS50 comparo anyway. Kudos for not simply phoning this review in and moving on to the next ‘big thing’ !

      • I’ve got something similar coming my way from Vanatoo that sells for considerably less than the X300A.

    5. This is a surprisingly informative short review. It makes me wanton of these “speakers”. It seems that they could be a real problem solver. Per-aps its time to start saving.


    6. Having heard both these and the AMAZING 50s at the Newport show, i realize they are not equal BUT I could certainly live with them in my kitchen computer system where I spend too much time.


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