KEF’s LS50 loudspeaker was introduced in 2012 to celebrate the English manufacturer’s 50th anniversary. Usually, anniversary models are large, floorstanding “statement” designs with a price to match, but the LS50 was a minimonitor, priced at $1500/pair. I reviewed the Anniversary Edition LS50 in December 2012 (footnote 1), writing that it was rare to find a loudspeaker that offers this combination of clarity and neutrality and concluding that within its limits of dynamic range and bass extension, the KEF LS50 “will provide Class A sound for those with small rooms.”
Sam Tellig agreed with me, commenting in May 2014 that he found the LS50’s tonality “spot-on, more neutral than sweet. Soundstaging and imaging were top-notch. Definition was superb, ranking with the very best speakers at any price.” Stephen Mejias was equally impressed, concluding in June 2014 that with the regular LS50 in his system, “there’s just so much more to enjoy—more body, more beauty, more control, more music.” (The regular LS50 lacks the words “50th Anniversary Model” below the coaxial Uni-Q drive-unit but is otherwise identical.)
I bought a pair of the non-anniversary LS50s after Stephen’s follow-up review, and I compared them with the equally superb-sounding but differently balanced and different-measuring Revel M106 in January 2015. Since then, I have used my LS50s as the primary reference for my reviews of standmounted loudspeakers.
Introducing the Meta
Now, eight years after its first appearance on the high-end audio stage, the LS50 has a successor, the LS50 Meta. The Meta is priced the same: a penny less than $1500/pair. It’s the same size—11.9″ (302mm) H × 7.9″ (200mm) W × 11″ (280.5mm) D (including binding posts)—and 1.4lb heavier than the original, at 17.2lb (7.8 kg). Visually, the only differences are an elegant matte finish compared with the original gloss and the fact that the chamfered rear panel now stands proud by one-tenth of an inch rather than being set flush.
The coaxial Uni-Q drive-unit, now in its 12th iteration, includes a new cone-neck decoupler and a symmetrical motor system, these intended to optimize the speaker’s dispersion. The cross-bracing inside the enclosure has been improved, but the main internal change is the incorporation behind the drive-unit of an absorptive, dual-layer disc, 3″ in diameter and 0.43″ thick. This disc is made from a synthetic substance incorporating Metamaterial Absorption Technology (MAT) developed by research organization Acoustic Materials Group for automotive and airplane use. As applied by KEF and optimized with Finite Element Analysis, this disc contains 30 tubular channels, each acting as a narrow-band Helmholtz resonator. The back wave from the tweeter’s diaphragm is coupled to the MAT disc with a conical waveguide behind the vented pole-piece. Polyester wadding in front of the absorber fine-tunes the absorption. The resulting structure is said to absorb 99% of the unwanted sound radiating from the rear of the driver at 620Hz and above (footnote 2).
Setup
My samples of the LS50 Meta had serial numbers LS50201763M29N1G and ‘1765M29N1G. “Designed and Engineered in the UK, Made in China” was written on the serial number panels on the speakers’ bases. Although KEF sells matching S2 stands, I set up the LS50 Metas on my usual 24″ Celestion stands, which had their single pillars filled with a mixture of dry sand and lead shot. The Metas were placed in the positions in my room where the original LS50s had worked well.
Amplification was provided by a pair of Parasound Halo JC 1+ monoblocks, these connected from the balanced outputs of PS Audio Directstream, MBL N31, and Okto dac8 Stereo D/A processors, each sent audio data from my Roon Nucleus+ server. The PS Audio and MBL DACs were connected to my network, the Okto to the Roon server via USB.
Sonics
The Meta’s low frequencies sounded identical to those of the original LS50. The half-step–spaced low-frequency tonebursts on Editor’s Choice (16/44.1k ALAC file, Stereophile STPH016-2) spoke very cleanly, with no emphasis on any of the tones, though the output was shelved down a little below 100Hz compared with the Marten Oscar Duos that had preceded the KEFs in my listening room and that Michael Fremer reviewed in November 2020.
And as I wrote in 2012, with the thunderous 16th-note sub-bass line in “Limit to Your Love,” from James Blake’s eponymous album (16/44.1k ALAC, A&M), the LS50 Meta was having to work harder than it would like to at anything approaching musically satisfying levels. A little higher in frequency, the fretless bass guitar that plays the melody on Michael Hedges’s version of “After the Gold Rush” (16/44.1k FLAC, from Aerial Boundaries, Wyndham Hill/Tidal) was reproduced with convincing presence and good separation between the evocative melody line and the same instrument’s low-frequency pedal notes.
The Metas painted a transparent window into the recorded soundstage, not just with this recording but with everything I played. I was continually surprised by how recordings I thought I knew well were presented with detail that I had not fully appreciated with the earlier LS50s. The Roon app’s Radio function reminded me that I should play Jon Hassell’s late-1990s album Fascinoma (24/88.2k FLAC, Water Lily). Kavi Alexander had captured the sound with a Blumlein pair of custom microphones designed by Tim de Paravicini. I had always felt that Kavi had placed the microphones a little too far away from the musicians in the highly reverberant chapel, but listening to “Suite de Caravan” from this album on the LS50 Metas, the wide-angle relationship between Jon Hassell’s upfront trumpet and Jackie Terrasson’s farther-back piano in the cavernous space clicked into focus.
While preparing this review, I had a Skype conversation about MAT with Jack Sharkey, KEF’s senior marketing and technical communications manager. Sharkey had urged me to listen to “New Frontier” from Donald Fagen’s The Nightfly. There are two versions of this album in my library, 24/48k ALAC files I ripped from a DVD-A, Warner Bros. R9 78138, and an MQA-encoded 24/448k FLAC version from Tidal. Both these versions have a more respectable dynamic range than the CD release, and while their levels seemed well-matched, the Metas revealed that there was a little more space between the instruments with the MQA recording, unfolded to 24/96 by Roon. The vibrato’d, chunky character of the Fender Rhodes electric piano was more evident than it had been with the original LS50s, and such detail as the faint cloud of reverberation around the instrument in the song’s coda was more readily deciphered.
Fagen’s lispy voice had a little more treble energy than it had with the 2012 LS50s, but it was more physically present in the room with the LS50 Metas; vocal images were especially palpable with these speakers. (I am reminded of something Bob Stuart had told me in the 1980s, that loudspeakers that have the same width as the human head always excel with vocal reproduction due to the similarity between the sounds’ intensities.) On the LP Fairytales (24/192 needle-drop from Odin LP03), the masterful way the late Norwegian singer Radka Toneff uses grace notes and the way she points the ends of phrases with vibrato were more clear with the KEF LS50 Meta than with the Marten Oscar Duo or the Bowers & Wilkins 705 Signature that I reviewed in December 2020.
I finished my auditioning of the KEF LS50 Metas with the Carpenters’ “Goodbye to Love” (DSD64 file, from A&M/Acoustic Sounds). I have always loved the way Karen Carpenter effortlessly phrases the song’s meandering melodic line. As with Fagen and Toneff, the singer was physically present via the Metas. And in the song’s coda, as the descending bass scales and ascending choral “aaahs” accompanying Tony Peluso’s fuzzed and compressed guitar solo faded away, it was as if the little KEF loudspeakers had opened a door into musical perfection.
Conclusion
The original LS50 might not have the low-frequency extension and power of the Marten Oscar Duo or the Golden Ear BRX that I reviewed in September 2020. Neither does it have the airy high frequencies offered by the Bowers & Wilkins 705 Signature. But to a greater extent than those three superb standmounts, the LS50 gave a palpable “reach-out-and-touch” soundstage. The LS50 Meta equals its predecessor in that respect but improves on its presentation of low-level detail and has a little more treble energy. As a result, it presents a more transparent window into the recorded soundstage without compromising the ability to communicate the music’s message. Highly recommended.
Footnote 1: This website reprint includes the subsequent Tellig and Mejias reviews.
Footnote 2: See “Metamaterial Absorber for Loudspeaker Enclosures” by Sebastian Degraeve and Jack Oclee-Brown, AES convention paper 10341, 148th Convention, June 2020. Available as a free download here.
NEXT: Specifications »
COMPANY INFO
KEF, GP Acoustics (UK) Ltd.
US distributor: GP Acoustics (US) Inc.
10 Timber Lane
Marlboro, NJ 07746
(732) 683-2356
kef.com
ARTICLE CONTENTS
Page 1
Specifications
Associated Equipment
Measurements
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