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Think about the future: an *active* KEF LS50 loudspeaker?

  • When KEF introduced the LS50 monitor – a modern day re-imagining of the legendary LS3/5a – it was intended as limited production run. KEF’s Hong Kong production facility would make enough to satisfy demand throughout 2012, not un-coincidentally KEF’s 50th anniversary in the loudspeaker manufacturing game, but once it was gone, it was gone.

    With the global audiophile community – from forum dweller to semi-pro reviewers to print-mag journalists – unable to hone in on any rival US$1500 standmount bettering the sound of the LS50, it sold by the veritable truckload and recognising they were onto a good thing, KEF extended production indefinitely (with the “50th Anniversary Model” assignation quietly disappearing from the front baffle).

    It’s easy to see why: the Uni-Q coaxial driver array does something special with imaging, especially in conveying the illusion of soundstage depth.

    Or perhaps the LS50’s strikingly modern look, rumoured to have been implemented at the behest of the GP Acoustics mothership despite some reservations from the Kent engineering facility, delivered just the right amount of KEF’s (traditional?) house sound in a future-facing box? Being priced within the reach of mortals didn’t hurt.


    In June of this year I pitted Rogers’ “65th Anniversary” take on the BBC LS3/5a against the LS50. The old timer still has it over the LS50 on treble sizzle and ambient detail but its restraint with dynamics means it just can’t rock out. The LS3/5a is without doubt far better suited to a simpler, gentler musical programme; it nails voices like no other bookshelf box, not even the LS50.

    For the modern audiophile though, the LS50 is emphatically where it’s at – better dynamics, deeper soundstage, greater low end authority. The LS50 is an all-rounder for those whose musical taste takes in contemporary indie rock, dub reggae and electronica.

    More importantly, the LS50’s pole position in the sub-$2k standmount loudspeaker sector has been hard won over a relatively short period of time; it has yet to benefit/suffer (your choice) from the reputation elevation of misty-eyed, vaseline-lensed nostalgia.

    And despite 2014’s blue and white variant being greeted with a mixed reception, it did nothing to dent KEF’s reputation as holder of the entry-level speaker cards. Me? I’m hanging out for the possibility of a Ferrari Red cabinet with a gold-bullion-coloured driver.

    On a DAR level: 1) I receive more emails about the LS50 than any other speaker and 2) even though a full two years have passed since publication my piece on three amplifier choices for the LS50 has maintained its position as one of the most read articles on this site.

    Subsequent to penning those thoughts, I extracted maximum cleanliness and drive from the LS50 with a trio of separates from Wyred4Sound. The mPRE pre-amplifier pushing into a pair of mAMP monoblocks bested even the junior mINT and even the high-current provision of the REDGUM RGi60. The mINT is the way to go for those eyeing the LS50 as a desktop option. And why not? With the listener sitting in such close proximity to the loudspeaker, the LS50’s coaxial driver array ensures the woofer and tweeter’s air displacement coalesce more readily before reaching the ear.


    However, the ‘which amplifier?’ conundrum surrounding the LS50 (like ANY passive loudspeaker) can sometimes lead the consumer facing myriad options to make no choice at all; the whole shebang gets filed in the too hard basket.

    BUT…what if having to choose an outboard amplifier were removed entirely? I’ve been pondering this since giving numerous hours to KEF’s more affordable X300A and X300A Wireless solutions: a DAC, twin class A/B amplifiers and loudspeaker loaded into each box and joined via USB. If there’s a better all-in-one system available for less than US$1000, I’ve not heard (about) it.

    The X300A are proof positive that KEF are hip to modern city living, that not everyone wanting good sound lives in a space capable of accommodating the physical intrusion of separate DAC, amplifier and loudspeakers. In short, box count matters.

    Out in the room on speaker stands, swapping out an LS50 + mINT combo for the X300A saw the active option surrender a little on transparency and frequency extension but – take note – layer separation acuity went up a few clicks. The upshot? Once activated, the technically inferior/cheaper driver – a Uni-Q from KEF’s Q100 passive – did some things better than a pair of LS50 powered by outboard amplification.


    On value, the X300A nail the LS50 to the wall. I’d concluded as much back in 2013. Reaffirmation came after I’d covered the Wireless iteration of the X300A in July 2014.

    Twelve months on and the mental presence of active loudspeakers looms larger than ever for this writer. Srajan’s KIH piece on the re-activation planted the seed. A seed that had begun to sprout by the time I hit Munich in May. Spying towering monoliths powered by trunk-sized monoblocks just doesn’t excite me. Is the future of high-end audio really tied up in so many boxes? I doubt it. With component matching taken care of by the manufacturer, active speakers are plainly more relatable.

    Since May, I’ve acquired a pair of Audioengine’s 5+ – a most splendid entry point – as well as a pair of Adam Tensor Deltas (as a direct result of what follows below).  A pair of Genelecs with room-correcting DSP are also on their way.

    Not only do active loudspeakers forestall the tyranny of amplifier choice and lower the box count but they strip loudspeaker cables from the equation. Ditto analogue interconnects if a DAC comes along for the ride.

    The theoretical advantages of internalising amplification are numerous: amplification housed in each loudspeaker brings mono-block-grade channel separation; an active crossover can be tailored to accommodate driver impedance swings; sitting post-crossover, each driver can be assigned its own amplifier; each amplifier talks directly to the the driver’s voice coil where it need only juice a specified frequency band (and not the entire range); amplifier classes can be mixed as/when required. Oh, suits you, Sir.

    Furthermore, designers taking crossover network execution into the digital domain can stir DSP-enabled room-correction into the mix.


    Compare this to the passive-driving outboard amplifier which must be brought to life without knowing what it will be powering. Consequently, the amplifier must be (over)-engineered to accommodate myriad impedance swing possibilities and for full bandwidth operation. Its signal passes through a (potentially) power-sapping filter crossover network comprising passive components – resistors, inductors and capacitors – so implemented to divvy up the signal between drivers and smooth any frequency response anomalies.

    The pick-n-mix approach to matching amplifier to loudspeaker leads to a higher probability of disagreeability – power shortfall, driver overdamping, tonal balance shifts etc. – more often than not determined by the end user after money has been committed.

    Worse still, an amplifier manufacturer’s claim that their design is “stable down to 2 Ohms” is sometimes UNconfirmed the hard way – an expensive lesson to learn whose bill is too easily footed by the consumer.

    One must therefore ask: why do so many audiophiles continue to shoulder the responsibility of matching off-the-shelf amplifier to passive loudspeaker when the technical superiority of a bespoke solution is all but guaranteed?

    Actives are also, pound for pound, less costly to make: is an amplifier’s chassis not its most costly ingredient?


    Of course, the recording studios wised up to active loudspeakers years ago. Ditto the pro audio and DJ worlds. Take a peek at any pro audio store’s loudspeaker section and you’ll see actives (and nothing but).

    I did precisely that a few weeks back. I dropped into Store DJ’s Sydney branch not once but twice. The questions burned on each occasion: could I source an active loudspeaker that would rival the sound provided by a pair of KEF LS50 driven by Vinnie Rossi’s LIO?

    The short and most emphatic answer is YES.

    Before we get to dishing the details, a little background is required.

    Store DJ’s sales staff were gracious enough to allow injection of my Pono Player’s line-out to feed a switchbox that would call any of their shelf-mounted monitors to life. As an interesting aside, 80% of Store DJ’s loudspeaker range comes in at under AU$1000. Talk about keeping it honest!

    Running favourites, the home-grown Event Opal 2, were M.I.A. due to “supply issues”. At AU$3599 they are by far the most deluxe active monitor offered by the Store DJ chain.

    On dollar value alone, the next model down were the Presonus Sceptre S6 (AU$1799) and Adam Audio A7X (AU$1899). Having heard a pal’s Adam Audio Tensor Delta, I already had the German manufacturer’s X-ART ribbon tweeter mentally pegged as a contender. Next to the smooth-sounding A7X the Sceptre S6 had the theoretical benefit of coaxial driver alignment but in reality their horn-loaded tweeters sounded several clicks too insistent.


    Maintaining Adam Audio focus, the difference between their A7X and the more affordable F5 isn’t just 2” of driver diameter and AU$1000; the former is considerably more transparent, readily discernible in-store despite the wall-o’-speakers approach to demos.

    I dropped by the Store DJ a second time to confirm findings before dropping my own hard-earned on a pair of A7X (no review loaner here) and sneaking a few smartphone snaps for good measure.

    Setup at home, the 7” driver sees soundstaging come on that bit too large for long-term desktop deployment – the 5” A5X would be more appropriate here – but those extra inches really come good once the A7X were placed on the Atacama Nexus 6 stands previously occupied by the LS50. For maximum consistency, pre-amplification came from the variable output of the LIO.

    What is it that keeps audiophiles away from monitors whose pro-sector marketing makes more of a play neutrality? Why is the N word entirely acceptable when pitched by their own kind but tainted by the notion of a divorced emotional quotient when heard from over the fence?

    Powered internally, the A7X’s tonal balance isn’t too far removed from that of the LS50 + LIO MOSFET amplifier combo. Room drive proved to be comparable. Ditto soundstage height and width. The A7X demonstrates a little more fluidity (and less grain) in the treble than the KEF setup. The latter show slightly more eloquent midrange expression. Where the Adams come up short is on soundstage depth, an entirely forgivable shortcoming in the context of the Stateside asking price where a pair arrives for the same as a pair of LS50 sans juicebox.

    I missed the KEFs not one jot once the Adam A7X had been serving main-rig duties for a few days.


    I’ve taken the long way ’round to arrive at the punchline: that the audiophile world desperately needs an active LS50. The British manufacturer are already fully across such wishes from your truly. I’ve been at them about it for well over a year.

    The X300A prove KEF have the chops bring it to market. But more importantly, the LS50’s near universal praise, combined with its comparative affordability, might be just the ticket to overcome the audiophile world’s reluctance to head down the active route.

    As buried in my coverage of the Eversound Essence, living spaces for millions aren’t what you’d call spacious; just ask anyone living in Tokyo. Fewer boxes not only make for superior aesthetic agreeability, but active solutions take away the guessing game of amplifier matching – they remove a layer of complexity. Not every audiophile prioritises the flexibility of amplifier switch ups over having those same electronics tailored for an optimal match.

    Moreover, simplicity and convenience move in lockstep with one another. Either will attract some much needed fresh blood to this ‘ere audio malarkey.

    By activating their iconic standmount, KEF would further increase the LS50’s relevance beyond that of traditional hi-fi stores. Done right (with optional DAC board) it’d have the potential to go toe-to-toe with Devialet’s Phantom and emerge victorious.

    Whilst I’m on a predictive tip, I’ll go one further: the future of high/er audio for this British manufacturer doesn’t so much rest with Blade or Blade 2 but with an active LS50. (I’ll take mine in red and gold, please).

    Your move, KEF.

    Further information: KEF | Adam Audio | Store DJ


    John Darko

    Written by John Darko

    John currently lives in Berlin where creates videos and podcasts and pens written pieces for Darko.Audio. He has also contributed to 6moons, TONEAudio, AudioStream and Stereophile.

    Darko.Audio is a member of EISA.

    Follow John on YouTube or Instagram


      • You and me both. I suspect Srajan will get the scoop on the Kii Three over at 6moons long before I get to hear a pair.

    1. Neat idea. I wonder if they could fit an amp in that cabinet? Maybe if they’d been active all along we’d be calling for a passive version?

      • Oh for sure! No doubt that audiophiles LOVE passive speakers but many are rather set in their ways in this regard, don’t ya think?

    2. Bravo! Bravo! Bravo! I ready your story with great interest as I’m already completely sold on the active loudspeaker approach. Dozens of manufacturers now offer consumer models configured that way. Unless you are into summit-fi territory, the advantages of a pair of mono active crossovers feeding a quartet (or more) of optimized amps are darn hard to beat. (Linn has beat that drum on the consumer side for decades.) My modest JBL studio monitors on my desk tell me that every day. I, too, would love to see a tricked out pair of powered KEF LS50s come to market as you advocate in this post. Given their sound profile and even some of their advertising, such a launch could happen simultaneously in the consumer and pro audio spheres to widen the net. Yes, DSP should be applied, in part to extend the bottom end. Personally, I just can’t get past the bass roll-off starting in the 70s Hz, and I don’t want to add a sub and risk mucking up the magic.

      Going even further upmarket, I wonder how the tri-amped monitors from Focal, Adam, Dynaudio, Genelec, ATC, etc, sound. How might their $7000 to $15k (and up)/pr sound compare to an equivalent amount spent on a really good consumer-grade rig? From what I’ve read and heard, they are a relative bargain, butt-ugly though some are. Perhaps you could get a pair of those in house for an “audiophile” evaluation and comparison.

      On a related note, how did the 7″ Adams work on your desk so close together and at such close range? When I listen to material with deep bass, I need to scoot back about 18″ to form an equilateral triangle with the speakers and my body for that frequency range to bloom and not sound “thunky.” (That’s what the owner’s manual specifies, too.) What I really need to do is put my monitors and their IsoAcoustics stands on a pair of tall stands in front of my desk, just like the pros do.

      • Hey BradleyP. Interesting thoughts on DSP. I wonder if going completely digital though will be a bridge too far for those wanting to add their own high-end DAC to the mix? One must overcome the (gut-level) objection to the additional ADC – DAC stage!

        I’ve been tucking into a pair of Adam Tensor Delta these past few days: it’s a *seriously* impressive active 3-way that, as you say, one would probably have to drop megabucks to best with a passive/amp separates.

        And I hear ya on the studio desktop monitor stand config. On the desk surface, even on IsoAcoustic stands, the 7″ Adams are great but a long way from being optimal.

    3. I have LS50’s and also the new Falcon 15 ohm LS3/5a with real KEF T27 and B110 drivers.

      Sure, the KEF plays louder but the Falcon is head and shoulders more musical than the KEF.

      Derek Hughes and Graham Audio are making an ‘LS3/5’ which is supposed to be even better, but we’ll just have to see.

    4. Despite limited reviews across the media, Meridian speakers have been championing this route for over a decade.
      Interesting the DSP3200 were often cited as having better imaging and soundstage than their larger offerings.
      KEF could partner with Meridian on the electronics?
      Maybe they’d both benefit?

      It’s time you reviewed some Meridian speakers and set a benchmark? The new DSP7200 SE perhaps?

      • Yes, the Meridian guys have indeed been at the forefront of development in this sector, but alas their offerings rarely fall under what most would refer to as ‘affordable’. Do/did those DSP3200 not sell for well over US$30K? An active KEF LS50 would turn more heads because it would probably come in at (well) under $5K.

        Besides, I’ve already sourced a pair of Adam Tensor Delta for benchmark setting.

        You do raise a good point though: that any loudspeaker manufacturer going active could easily stuff it up if they don’t get the electronics right. Proper partnering and/or consultation is key.


          At $6k new they’re probably a steal used.
          At $30 odd thousand the DSP7200’s come in and compare to Wilson Sasha or B&W 802’s with very spend electronics.

          The bigger problem is convincing worldwide audio enthusiasts that active and DSP is the future – it’s taken long enough to see digital sources lead the way!

          If KEF can come up with some electronics to match the magic of the LS50’s they’d have a winner for sure. Heck, how about making ethernet a source option…

          • And that’s my point: for any manufacturer to convince audio enthusiasts of the case for active, it needs to come from a loudspeaker brand with pedigree AND be affordable.

    5. I haven’t switched to active probably because I’m afraid I’d be lost without the good old integrated amp all-in-one hub that I’m so used to.
      Just two speakers in the middle of the room – no DAC, no pre, no amp, no VU meters, no LEDs nothing to stare at or show off?
      I consider myself somewhat of a minimalist and while I don’t go for the sound altar or towering rack-o-gear looks I’m still attached to ”the hub”
      Active with a pre or active in a desktop setup – maybe. For the living room? Not yet doctor.
      Kef, no need for grills but please lose that orange driver in the black version. Something more traditional please and I might consider.

    6. ‘Music to my ears’

      A subject on active loudspeaker design as I am listening to my active Meridian M20’s which I have owned since right after introduction. (That was a long time ago-they use KEF drivers as you may know)

      Those speakers launched me into ATC SCM 50 ASLT actives some yrs ago which are in my main system. However my recent foray into the KEF X300a didn’t go as well having needing to service them twice in just over one yr where the electronics kept failing .. Otherwise actives have been a positive experience for me for over two decades.

      What’s a power amp again?

      Happy listening…

    7. Great article John.

      It made me smile to think about how I approach products like the Devialet Phantom. I see myself as a relatively ‘progressive’ user of technology as I have gone fully digital for a few years now.
      I was shopping for new gear this year and took a hard look at the Avante Garde Zero 1’s. In the end I wasn’t really captivated by their sound but what I found notable was my own trepidation at no longer being able to mix and match components to move the sound in the direction I wanted. I currently have numerous ‘levers’ I can pull to get the outcome I want. With products like the Zero 1 and Devialet I would no longer have that option (eek!). I knew that there were numerous benefits of such a beautifully integrated system and I wanted to embrace the approach but the lack of control was my single biggest concern. If I didn’t like them there was nothing I could do (other than replace them).
      But I recognise that is not how the rest of the world approaches the search for a better sound. I think that an active KEF LS50 would be a great landing spot for those moving up from a UEBoom and the thousand other bluetooth enabled units. If they could combine ease of use with true high quality sound that only requires BYO source then it would provide a realistic and practical solution to thousands currently stranded with ‘lifestyle’ products that prioritize convenience over sound. If we want to understand how to help people get more pleasure from their music (and I do) we need to really understand where the sweet spot of convenience, quality and value sits because every journey begins with a single step.
      Regards David

    8. I would buy active LS50s if they existed. And I’m not just saying that – I would actually buy them. (Hi KEF). But I would have to spend a long time saving up for them, and would have a hard time justifying their purchase to my partner when they’d be in the $3K – $5K range. I’d probably have a hard time justifying their purchase to myself, tbh.

      So, other speakers I would like to get the “active treatment” are: Usher S-520 and Magnepan MMG. Both cost considerably less than the LS50, but have the reputation of being good value with the condition that you give them a decent amount of power (especially the MMG). The reality is that when it comes to buying a capable complementary integrated amplifier at parity value (<1400 AUD), you're gonna have a tough time (from what I've observed, at least).

      Active MMGs are really the dream for non-desktop set ups IMO – no bookshelf stands required!

    9. I’ve had the fortune of trying lots of HiFi at home and indeed went through an LS50 ‘phase’ a couple years ago with a Pre, Dac, Monoblocs, God knows how many cables etc. Taking a pair of the X300’s home for a curious listen turned out to be the most shocking audio experience of my life – used nearfield, they were actually better in quite a number of ways and at about a fifth of the price. A fifth!!!
      Sure enough, i flogged the LS50’s and every single bit of accompanying gear and set down my active/powered road.
      Currently the Focal Solo 6 Be’s are the zenith of my journey, and (with alternating DAC/Pre’s) they’ve stunned Hifi sales reps and retailers alike. “How, just HOW, do they image like that?!”. But i’m always on the hunt for better…

      The trouble with Meridian as they are too ‘Lifestyle’ for your average fella, meaning there’s a few more zero’s on the price tag than there really needs to be. Engineered to be exclusive, i’d say, but they are on to something from a clean and minimalist POV.

      I also think that anyone who prefers having a gazillion boxes and cables simply prefers all the fiddling and upgrading of a system because they are addicted to Hifi, not music. For the most part, Hifi is a wealthy man’s game. A huge sprawling system is little to do with value and more to do with megalomania.
      And it’s true, the case/chassis is the most expensive part of most Hifi, so think about that in value terms when you have 7 boxes doing what 2 can.

      Chances are that if you are on this website in the first place then you are quite likely a ‘desktop listener’ and are already aware of the virtues of active speakers. If not, then hopefully you will be soon!

    10. Would I purchase an active LS50, if funds allowed? yes for situations where multi box kit isn’t suitable. If ‘active’ speakers are a step towards good sound with a nod towards convenience then that’s fine, however for me it’s just a step towards the traditional one box radiogram approach which is of little interest to Audiophiles who would prefer to have an upgrade step when funds become available. For me they are convenience lifestyle items even taking into account driver amplifier matching etc. . Just an open and honest opinion.

      • I don’t think see quality and convenience as mutually exclusive. The KEF LS50 could provide the right buyer with a happy medium. Perhaps even more so: a small surrender on SQ (assuming one can locate a good amp match) for a drop in box count.

    11. Perhaps you could try out the focal solo6 be and see how that compares? The price puts it as a competitor to the ls50 and it’s pretty well reviewed too!

    12. Great article, thanks John.
      I started on the powered speaker path with a pair of Paradigm Shift A2s. I now have 4 pairs dotted around the house, each driven by an Airport Express. These are very versatile little DSP speakers that work well for either near field listening or rocking out and sound surprisingly good connected directly to a laptop or wifi hub. I now have a pair of Genelec M040s in my main system, driven by either a Pioneer DJM-850 or a Chord Hugo, depending on what I’m up to. Again, awesome sound with great versatility – can’t see myself going back to a traditional setup and it’ll be very interesting to see how the field develops over the next few years.

    13. Wow such a good entry!

      I have a bit of a studio background and so was used to active monitors. I was always a little disappointed when it came to hearing hifi speakers that cost the same amount and without the amp!

      I’ve been searching for the perfect bookshelf style studio monitor and after trying many, many different brands I finally found the Adam A7x as well. They are really great even if their looks leave something to be desired.

      Since reading you’re blog though and dropping in and out of 6moons I have wanted to find a nice digital lossless streaming solution that I could control with an iOS device.

      So far that’s A7x plus XLR cables to preamp to DAC to streamer. Still a few boxes.

      I heard rumours about the Devialet Phantoms and then I went and auditioned them. I spent two hours with them with all kinds of music in a living room style listening room. I couldn’t quite believe what I was hearing – everything worked well regardless of genre.

      The dealer then took me next door to another room where he had setup some Kef LS50s connected to a nice streamer and amazing DAC (Metrum Octave) – a system coating around €10,000.

      Now I have really enjoyed the kef ls50 when I’ve had the opportunity to listen to them before. But compared to the Phantoms they sounded box-y. I was a little shocked because I really like them. I looked at the dealer with a look that said “why do they sound not so great?” And he looked at me and said ‘I know’. He added “I don’t know how I’m going to sell all of these other speakers!”

      So if you’re going to spend around €4,000 for everything (streamer, DAC, cables, sub, speakers) then I strongly recommend the phantoms. Even compared to the Beloved A7x which might be a tad clearer, overall the phantoms win and the convenience of no wires/boxes anywhere. The only downside is that upgrades are not possible except through the often needed software updates.

      But even against the venerable LS50 with amazing amping and dac-ing, the phantoms still won. I then got them on home trial and have decided to purchase two silvers and a dialogue.

      Many confuse them for a lifestyle product but that misses the point completely.

    14. Great article!

      For those looking for a great active setup on a budget I can highly recommend the JBL LSR305 (~$425 AUD a pair). They have replaced (and sonically exceed) my budget separates (redgum sonofagum, paradigm atoms) which I was very happy with. Great bang for buck speakers just add DAC.

    15. Another, smaller player that has been championing the active approach for a few years now in Australia is SGR. In fact, I have been contemplating moving down the active route ever since hearing a pair of their CX4F floor standers, just never had the budget. You have inspired me to look further!

      • Yep – I mentioned ’em in an earlier piece I believe. Stuart Ralston has brain the size of a planet.

    16. An active LS50 would very tempting however I am fully enjoying my X300A, corrected with Dirac Live digital room correction, in my 20m2 room. The only thing I would wish for is a subwoofer output, so if KEF decides to design an active LS50, please do not forget a subwoofer output!

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