Introduction - what is the LS50 Meta?
The KEF LS50 Meta is a two way standmount speaker. It is a revision of the original LS50 which has been a huge hit for KEF in the eight years it has been on sale. There are a few reasons why this is the case, and it’s important to stress that KEF hasn’t messed with the basics in the creation of the LS50 Meta.
One of the most important of these is that the LS50 exists as a solo model (albeit in both passive and active versions) rather than as part of a range. By grouping it in the same category as the Blade and Muon, the LS50 was pitched as a bit of affordable esoterica. Of course, it helped that it was rather good too. Anything that survives eight years in production unmodified, barring various limited edition finishes, which varied between the very lovely and utterly unlovely, has to be fundamentally sound in design and execution.
All things must change though and here we are with the updated version. Is the basic design still sound enough to compete? Do the changes warrant the price increase over the old one? Has the competition caught up? All this and more are on the list of things to cover.
Specification and Design
The LS50 is a two way design that leverages a key part of KEF’s engineering to do what it does. KEF wasn’t the first company to look at a coaxial driver arrangement and neither is it the only company to continue to make them but few other companies have put as much engineering time and effort into their development as KEF has. The Uni-Q driver has been in a process of continuous evolution for decades. The principle of what it is, i.e. the process of mounting the tweeter in the ‘throat’ of a mid bass driver to syncronise the axial performance of both, hasn’t changed but the technology that makes it happen has continued to evolve.
Before we get stuck into what has been improved this time, it’s important to consider that the LS50 is shaped - literally - by the Uni-Q driver. It is a two way speaker that only requires a single perforation in the front panel. This means that the front panel can be shaped in a way that wouldn’t be possible if there were two drivers. This allows the use of the immensely stiff Dough Moulding Compound - a glass fibre and polyester combination that creates an extremely stiff and inert assembly. The driver can be mounted in the centre, which ensures that the forces it exerts back are evenly dissipated.
This baffle proceeds to work with the driver in a way that is governed by the driver’s natural attributes. The driver is designed to behave as a single point source and the baffle assists this in curving away at the edges, helping the LS50 Meta to generate the stereo image that it does. The baffle then attaches to the rest of cabinet, which is heavily braced, and uses constrained layer damping to ensure it is suitably inert. The driver is augmented by a surprisingly long rear port that uses computer modelling to assume the form that it has. The most notable aspect of the port is that it is soft and deformable which KEF says is key to avoiding unwanted turbulence.
New for the LS50 Meta - and indeed the reason it is so named - is the arrival of metamaterials. The full name is Metamaterial absorption technology and the reason is has been deployed is down to a characteristic of all dynamic drives, be they Uni-Q or more conventional. When a driver radiates energy out toward the listener, some energy is also produced that radiates energy back into the cabinet. This is reflected and then proceeds to make its way forwards, muddying the signal that is leaving the driver. KEF’s approach to dealing with this is to create a shield made of this metamaterial and place it over the rear of the driver. Inside the shield is a network of channels that proceed to dissipate this energy and ensure it isn’t reflected back. More than anything else, this Metamaterial shield looks like the Maze motif in Westworld but KEF is extremely proud of its creation. This is its first production use but the assumption is that it will roll out to other models in due course.
This concentration on reflections means that the quoted performance of the LS50 Meta is relatively similar to its predecessor. KEF has dropped the crossover between the tweeter and midrange to 2.1kHz and there are some other detail tweaks but the idea is that there wasn’t a huge amount wrong with the physics of the original LS50 and that the basic rightness continues as before. This means that KEF quotes a frequency response of 79Hz- 28Hz at +-/- 3dB and 47Hz-45kHz at +/- 6dB; one of the widest disparities I can remember seeing. Tucked alongside these figures is the innocuous ‘Typical in room bass response’ which is an eyebrow raising 26Hz. More on which later.
These similarities with the original LS50 extend to the rather stiff minimum impedance of 3.5 ohms and quoted sensitivity of 85db/w. I have long regarded KEF as nigh on fanatically honest about its measurements which means that it can sometimes come across as unforgiving compared to speakers that - if measured in the same way - would hit similar figures. Nevertheless, these numbers have some significance to the performance of the LS50 Meta we’ll cover in due course.
In appearance terms, save for a tidied up rear panel, there are few changes to the basic styling of the LS50 but that’s not too surprising. In eight years of availability, including a level of market penetration that pretty much extended to ‘normal’ people, we became used to the LS50. Take a look at it with fresh eyes though and this is still an exceptional looking bit of kit. In the white finish in particular, this is still an extraordinarily unadorned, almost minimalist device. The combination of stark cabinet and the Uni Q, which is festooned with the evolutionary details that have appeared in successive generations, is one of the most striking pieces of design at the ‘quasi sensible’ end of the market.
Like all distinctive and different things, enthusiasm is not unanimous. Two friends of mine greatly dislike them while another bought a pair of the original wireless LS50 in the week they came out and will most likely swap them in for the new version because in their (rather more elegant than mine) living space, nothing looks as good to them as the KEF does. I’m somewhere between these two positions. My living space is perhaps, a little too ‘adorned’ for the LS50 Meta to look perfect in but I admire KEF’s boldness. I also have absolutely no complaints about how they are bolted together. They might now be a £1,000 speaker but there’s not much in the way of £1,000 speakers that have any advantage over the KEF.
Take a look at it with fresh eyes though and this is still an exceptional looking bit of kit
How was the LS50 Meta tested?
As it was unclear what running the samples had done before arriving, they were used on the end of a Naim Supernait 3 and ND5 XS for general listening for a few days before critical listening was undertaken. This was done in two stages; the first using a Cambridge Audio Edge A integrated amp connected to an IsoTek Evo3 Sigmas mains conditioner and taking a USB feed from a Roon Nucleus. The second was using a Rega Brio and Chord Electronics Qutest, again running from the Roon Nucleus for signal, in order to see what the KEF did with slightly more price comparative equipment. Material used has been FLAC, AIFF, DSD and some streaming service content from Tidal and Qobuz.
More: Audio Formats
It has been five long and busy years since I spent time with the original LS50 in a home environment (and not the same home environment as this one) so audio memory has faded to nothing. Nevertheless, reading over my old notes for the LS50 before writing this was instructive. In essence, the KEF takes the strengths of its predecessor and runs with them, never losing the basic character of the original but tweaking the attributes on offer too.
Connected to the Cambridge Audio, the KEF delivers the same impressive selection of abilities as the original. It takes what the Uni-Q driver is naturally good at and uses the form, cabinet and supporting engineering to deliver the definitive Uni-Q experience. So long as a little care is taken with the placement, the KEF delivers an astonishingly immediate and three dimensional listening experience that has very little perception of the cabinets in it. Following the ‘trad but not’ Spendor Classic 4/5 though testing, the LS50 Meta has to give ground to the incredible midrange immediacy of the Spendor but it has a level of scale and bass response that the Spendor cannot get near.
And the metamaterials? Again, it is not possible to compare old with new but there is a clarity to the KEF’s performance that can almost certainly be chalked up to you hearing only what the drivers project and not what they reflect. They dig details out of the audiophile catnip that is Oh Woman, Oh Man by London Grammar and place them in that assured and defined space in such a way as to appreciate them but not to the level where you lose sight of the bigger picture. The bass extension is superb too. I don’t think that the sub 30Hz is viable without being close enough to a wall that it would be audible but I don’t know of many two way standmounts at similar money that can get near.
This also improves the perceived speed and clarity of the performance too. The LS50 Meta tears into the thoroughly unaudiophile Disbelief Suspension by Mark Lanegan. Without compromising on the technical ability, the sheer fury of the track is delivered in a way that appeals at an emotional rather than a critical level. I’d hesitate to describe the KEF as a forgiving speaker; it wants to tell you everything about what is going on, including the shortcomings of material. The manner in which it does this is sufficiently benign that it is unlikely to result in you putting parts of your music collection off limits to them.
Making comparisons to the Spendor- a speaker that costs 60% more than the KEF - isn’t the limit either. Used in the same test context as the JBL HDI 1600, PMC twenty5 21i and Neat Ministra, all speakers that are getting on for (or indeed are) twice as expensive as the KEF, the LS50 Meta genuinely holds its own. In terms of clarity, soundstage and sheer impact, it’s genuinely competitive with any of them. It has to be seen as something of a bargain in terms of the outright performance potentially on offer.
There’s a ‘but’ coming though. The thing is that it’s a ‘but’ that needs explanation and qualification because, depending on how you intend to use the KEF, it’s not necessarily a ‘but’ at all. The KEF stands comparison to the PMC 21i, a speaker that costs exactly twice as much. The catch is that to achieve this, you will most likely have to partner it with equipment of at least as good a quality as you would for the £2,000 PMC and possibly better. I’ve been intrigued by the small but consistent narrative from a group of people who had bought the original LS50 and simply could not get on with it. I think that in large part, this will come down to partnering equipment.
Case in point comes when I switch over to the Rega Brio. I love this amp and I have in the past run speakers up to and including the Focal Kanta No1 on it and thoroughly enjoyed the results. It’s partnership with the KEF was - bluntly - not good. Whether it’s a quirk of impedance or one of half a hundred calculations that determine the relationship between amp and speaker, the result was very much not greater than the sum of its parts. Whereas when I tested the PMC, I noted, it would work with equipment that cost rather less, flatter it and be ready for the next round of upgrades, the KEF isn’t that way inclined.
It has to be seen as something of a bargain in terms of the outright performance potentially on offer.
- Outstanding depth, scale and imaging
- Consistently fun to listen to
- Handsome and well made
- Fairly demanding electrical load
- Will not act as an automatic 'quick fix' to improve every system
KEF LS50 Meta Standmount Speaker Review
As I say, if the limits of my criticism toward the KEF extend to noting that it needs to be treated to some decent partnering equipment, you may - correctly - infer that this is one hell of a speaker. KEF has taken a concept that was always sound and made it even better. The result is a monumentally capable speaker, one that really does make good on the ‘affordable high end’ strapline. What is isn’t is something that will unconditionally deliver on this promise regardless of what you connect it up to. While you don’t need to budget for a Cambridge Audio Edge A, I would suggest that an amp that costs at least as much as the LS50 Meta and disposes of at least 70 watts with decent performance into a four ohm load would be a good place to start looking.
Work with it and the result is a superb speaker. The KEF is able to perform feats of soundstaging, time alignment and sheer impact that are an absolute delight. The KEF isn’t a one stop solution to greatness as may have been suggested elsewhere. What it is though, is a sublimely talented device that shines with the right partnering equipment. For these reasons, the LS50 Meta comes Highly Recommended.
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