Few audio companies can claim a history anywhere nearly as rich as the one KEF enjoys. Not only has this company, based in the United Kingdom, recently celebrated its 50th anniversary, but in an industry rife with short-lived ‘me-too’ products, KEF strives to create distinctive solutions while possessing the necessary skills set to produce uniquely-engineered products. In particular, the proprietary—and sophisticated—Uni-Q driver concept, which sits the tweeter within the midrange driver, sets KEF apart from the crowd.

To celebrate this 50-year acoustic milestone, KEF released a small monitor loudspeaker aimed squarely at the high-end market—and straddling nearby borders with professional studio aspirations. In fact, the design inspiration was the legendary LS3/5A studio monitor from the 1970s, which in early iterations used KEF drivers and went on to make a name for itself in BBC studios around the UK and in radio studios around the world.

Crossing Bridges
Coincidentally, my reviewing schedule had the KEF LS50 following the superb Grover Notting Code 4 speakers. Both are standmount designs, though the KEF’s cabinet is smaller—and ported—compared to the Code 4s, which have larger enclosures that are completely sealed.

Also common to both is the converse idea of an established consumer brand promoting its speaker as a studio monitor in the LS50, and a professional monitor making inroads into the domestic environment in the Code 4. As I mentioned in the Grover Notting’s review, when a speaker aspires to accurate sound, the borders between domestic and professional become blurred. The LS50 is a gorgeously-designed and diminutively-proportioned standmount speaker in a gloss piano black finish with a curved baffle that is covered in a low-diffraction ‘rubber-like’ material. It’s a design which would not look out of place in the techiest of studios or the poshest of homes.

The speakers feature a new coppercoloured—KEF calls it ‘rose gold’—130mm Uni-Q driver with trickle-down technology from the mighty Blade, KEF’s flagship loudspeaker. The quoted frequency response is a fairly wide (for what could almost be called a mini-monitor) 47Hz to 45kHz ±3dB with KEF claiming a nominal impedance of 8Ω and a sensitivity rating of 85dBSPL.

At only 7.2kg the LS50 is easily carried around for location monitoring if need be, however I think this is a high-quality domestic speaker at heart or, as represented in various marketing images, as a permanent fixture perched atop a console in a studio mastering suite.

Lightweight it may be but the LS50’s small enclosure is well braced and feels sturdy enough to the industry-standard ‘knock on the side’ test. KEF has used constrained layer damping for the panel walls and reinforces the small enclosure with four cross-sectional bolts that couple the front baffle to the back panel. For the odd periodical adjustment and tightening, removable rubber caps on the rear panel provide access to the hex-headed tensioning bolts. Post adjustment, the caps can be popped back in place but are somewhat loosely held and, if not inserted back carefully, can drop out all too easily (indeed the speakers I was loaned for this review were delivered with one cap missing).

The rear panel also features an elliptical port which has been treated with a material that’s similar to that which covers the baffle and is flared inside and out. Both the port’s shape and its lining are intended to reduce chuffing and general port noise.

The little LS50 bears the fruit of KEF’s considerable R&D resources and advanced engineering which features Finite Element Analysis and Computational Fluid Dynamics techniques.

Sound of the Studio?
After firing them up in my reference system the KEF LS50s had me surprised at the bass levels these small speakers were capable of delivering. The design does not defy the laws of physics by digging into the deepest depths of bass but what it does above a perceived 50Hz (give or take a few Hertz) is well-controlled, detailed and pleasingly visceral. I constantly needed to remind myself the LS50 is a small speaker with a 130mm driver with reduced surface area due to the inclusion of the tweeter assembly within it.

The use of a Uni-Q driver in a monitor with a relatively narrow and rounded baffle translates to extraordinarily exacting focus with images precisely placed within a very wide and extremely deep soundstage. Depending on the nature of the recording, I was sometimes pleasantly surprised at musical and instrumental information the LS50 seemingly placed way behind the speaker plane—Ani DiFranco’s Amazing Grace from Living in Clip and any track on Harry Belafonte’s Live at Carnegie Hall are supreme test beds.

The Uni-Q’s midrange is rich, resolute and forthright. Vocals are projected to the fore, but not overtly or unsavourily so. The side effect of this slightly forward midrange sees the delicate and sweet highs sounding a tad laid back but not muted. On the other hand, such a presentation provides a rather enjoyable ‘presence’ factor to well-recorded vocal performances.

The whole frequency range has the ability to separate demanding passages into distinct musical strands, each with its own individuality in terms of spatial position and timbral signature.

The LS50 offers a dynamic range capability that is very impressive, irrespective of speaker size.

Powerful drum tracks and well-recorded uncompressed material provide the jump factor that is quite the persuasive verisimilitude of the live performance. The Tony Dagradi Trio’s Live at the Column’s Limbo Jazz is one of the most dynamically powerful recordings I have ever heard. The little LS50 pulls no punches. Really, that small driver is doing some heavy lifting in this speaker, both in terms of bass punch and sheer dynamic clout.

Will the KEF LS50 live up to the revered LS3/5A’s legendary excellence? Has it fulfilled the aspirations of both the domestic and professional sectors? I asked myself these questions and in my opinion the LS50 certainly has the sonic fortitude to excel in all manner of high-quality audio systems, whether they’re used in domestic or professional situations. So, barring the thinning concept of longevity, I’d say that given its heritage, the outstanding build quality, the technical sophistication of the Uni-Q driver and the superb sonic qualities, KEF’s LS50 Anniversary speakers answer all these questions with a resounding… ‘Yes!’ 

KEF Model: LS50 
Category: Standmount loudspeakers 

+ Sophisticated Uni-Q drive unit 

+ Excellent overall sound and bass depth 
+ Attractively styled and finished 

- Highs are a tad laid back 
- Rubber grommets on rear baffle drop out

Warranty: Five Years
Distributor: Advance Audio
Address: Unit 8, 509–529 Parramatta Road Leichhardt NSW 2040
T: (02) 9561 0799

Thank you for searching out the equipment review of the KEF LS50 Anniversary Speakers that was originally published in the Esoterica section of Australian Hi-Fi Magazine, Jan/Feb, 2013 (Volume 44 Number 1).

This equipment review consists of a full subjective evaluation of the KEF LS50 Anniversary Speakers written by Edgar Kramer (reprinted above) plus a complete set of independent laboratory tests conducted by Newport Test Labs and an analysis of those test results, written by Steve Holding.

Test reports and graphs are available only on a low-resolution pdf version of the original magazine pages: download pdf here: KEF LS50 Anniversary Speakers Review and Test

POSTCRIPT: If you intend to use a subwoofer in conjunction with the KEF LS50s, you will need to set its volume, phase and crossover controls correctly. You can find full details of how to do that HERE.