KEF LS60 Wireless Floorstanding Loudspeakers Review
John Pickford is beguiled by this beautifully designed, premium-priced wireless floorstanding speaker system…
LS60 Wireless Loudspeakers
AUD $9,995 RRP
In celebration of its sixtieth anniversary, KEF has pulled out all the stops to deliver the LS60 Wireless. It's an active floorstanding loudspeaker incorporating bespoke onboard amplification and comprehensive streaming capability – a complete all-in-one system. If streaming is your thing, you can power up these beauties, download the KEF Connect app and play hi-res music from your chosen service without needing extra boxes or cables.
It's a slim, elegant design reminiscent of KEF's flagship Blade, albeit without the sexy curves of the top model or, indeed, its movie star price tag. That's not to suggest it's in any way dour, though, as the subtle but stylish appearance of the LS60 W makes it easy to fit in with pretty much any décor – and it looks even better in the flesh than in the pictures.
KEF calls it “the world's first Single Apparent Source wireless system, aiming to achieve the acoustic ideal of a point source, where low, mid and high frequencies radiate from one point.” Now that's a design concept of which I wholeheartedly approve!
Attached to the front baffle is a new, smaller version of KEF's super Uni-Q driver array as used in the Blade and ever-popular LS50. Designed specifically for the slim profile of the LS60, this new driver features a 10cm aluminium midrange cone combined with a 19mm vented aluminium tweeter.
It's mind-boggling to think that the Uni-Q is now in its twelfth generation, and this latest revision features KEF's innovative Metamaterial Absorption Technology (MAT). Supposedly, this eliminates distortion by absorbing ninety-nine percent of the unwanted sound from the rear of the tweeter, acting as a sort of “acoustic black hole”, in the company's own terminology. Other refinements include a tweeter gap damper and new Z-Flex surround, which KEF says ensure a near-perfect transition of sound from the speaker into the room.
Flanking the Uni-Q on the sidewalls of the cabinet are two pairs of 5.25-inch Uni-Core driver arrays, similar in design to the 6.5-inch version used in the KC62 subwoofer. Mounted back-to-back in a force-cancelling arrangement to minimise distortion, the low-frequency performance is further optimised with KEF's P-Flex and Smart Distortion Control Technology. As the drive units are situated in the top half of the enclosure, a heavy base plate is used to keep the speakers stable and prevent them from toppling over.
Very unusually these days, this is a sealed box design – there is no bass reflex port to aid low-end output and speaker efficiency. There are several drawbacks with ported designs, the worst being that they can have sluggish bass and overhanging resonance that produces the dreaded 'one-note bass' effect. Curious as to how this design achieves a quoted low-frequency response of 26Hz without the aid of a port, KEF responded to my query in detail, and I found the following extract most illuminating…
To achieve a flat frequency response in the bass, a substantial amount of extra gain has been applied to the LF. This gives the bass extension that a port typically provides. However, this approach does require care, as the digital signal chain including amplification has the potential to blow the drivers. This necessitated the development/use of the Intelligent Bass Extension technology, which controls the bass extension of the speaker in real time in a natural way, resulting in drivers that are well protected from any incoming signal, while still utilising them to their full potential.
To summarise this, it's an active, adaptive bass boosting system. Low-frequency gain is supplied by 500W of Class D amplification into each loudspeaker, with a further 100W of Class D driving the midrange. The tweeter is treated to 100 watts of traditional Class A/B power, to extend the upper frequencies to a quoted 36kHz. Using Class A/B exclusively would necessitate heatsinks far larger than the slender cabinet would allow; heat from the LS60's amps is dispersed through a vent on the rear of the enclosure.
The LS60's wireless streaming comes courtesy of KEF's highly regarded W2 wireless platform introduced on the Applause Award-winning LS50 Wireless ll. So you can use Wi-Fi, Apple AirPlay 2, Google Chromecast and Bluetooth. Once you've downloaded the KEF Connect app, you can stream popular services such as Qobuz, Deezer and Amazon Music.
You need this app to set up the system; however, it is quick, easy and intuitive to use. I was happily streaming from my Qobuz library within a few minutes of download. Other streaming services, specifically Spotify Connect, Tidal Connect and QPlay, are available via native apps, and this forward-looking system will be Roon Ready. However, the LS60 W is still pending Roon certifications at the time of review.
DSD and MQA decoding is supported, as is the streaming of PCM files up to 24-bit/384kHz; however, the LS60's wireless playback downconverts this to 24/96. Streaming files at 24/192 is possible by using the supplied cable to connect the two speakers. The primary speaker features sockets for optical, coaxial and RCA connection, so you can connect external sources such as CD players or a turntable/phono stage combo, while both speakers allow connection of a subwoofer. And should you wish to use the LS60 with your TV, there's an HDMI (eARC) port.
The KEF Connect app can optimise the system for any environment, so if your room is furnished with shag-pile carpets, thick curtains and sofas festooned with cushions, then you should move towards the 'Damped' setting. Alternatively, go for the' Lively' option if you have wooden floors, lots of glass and few soft furnishings. The default 'Moderate' setting is best for acoustically optimised rooms. As well as room acoustics, the basic EQ lets you tailor the sound to suit speaker placement.
These controls are powerful, and it's easy to overcook things when you make adjustments. Used judiciously, with reference to the Default setting, you'll know when you've got the speakers singing sweetly. The Expert mode lets you do similar things in a rather different and more involved way, as well as allowing you to turn off the speakers' default phase correction technology, for example. I set up the LS60 Ws per KEF's guidelines, with the listening position forming an equilateral triangle with the speakers. As my moderately damped room is 22 square metres, I could place them in free space, so the default EQ setting proved best.
This speaker system's performance can be neatly summarised in two words – coherence and control. Coherence comes courtesy of the Uni-Q driver array and its position in regards to the Uni-Core bass drivers, forming the desired point source. Some listeners pay no regard to this topology, but I'm a long-time fan. After all, I interchange Tannoy Dual Concentrics with Quad ESLs in my main system, and both sets offer a point-source presentation in their own way. What you get from the LS60 Ws is a focused, all-of-a-piece sound, free from time-smear and the sort of phase problems that can occur when you have multiple drivers located at various points on the front baffle.
Control is a result of the system's superlative bass response. The LS60 digs deep yet remains tight and tuneful, the amps keeping an iron-fisted grip on the lowest frequencies to avoid a slow and sloppy bottom end. These speakers pack a punch when the music demands, yet are not overtly punchy in terms of character; there's no subjective mid-bass hype to beef up bass-shy recordings.
Take Lawn from Aldous Harding's superb new album, Warm Chris, for example.The track features a swooping, swampy stop/start bass guitar line underpinned with a slack tuned, underdamped kick drum, which remains distinct through the system as the bone-dry bass contrasts with the ring and studio ambience surrounding the drum.
Rhythms are another beneficiary of the KEF package's commanding authority, with no bloated, lagging bass boom slowing things down. This first caught my ear during a late-night, low-level play-through of Carole King's Tapestry, an album I'd never thought of as particularly groovy. Yet It's Too Late swung infectiously with agility my big old Tannoys sadly fail to deliver.
Such control and coherence is not limited to the system's fine rhythmic alacrity, though, as tonally, the LS60 is beautifully balanced from top to bottom. Midrange and upper frequencies are smoothly presented, offering plenty of detail without the exaggeration or treble hype of some modern loudspeakers. Ambient cues aren't masked by an overly prominent lower treble that pushes dry, finely etched details at the expense of air and spaciousness.
Echo and the Bunnymen's Ocean Rain album has a liberal dose of studio reverb added to most tracks, and I was overjoyed to hear the icy atmosphere of The Killing Moon replayed through the big KEFs without the grating sharpness it takes on through leaner and more brightly balanced systems. Impressive stuff!
KEF is onto a winner with the new LS60 Wireless. It's a very powerful premium active speaker system capable of both thunderous dynamic swings and subtle microdynamics. Instrumental timbre is portrayed naturally and convincingly, and tonal balance is extremely accurate. However, this isn't the 'warts 'n' all' accuracy of studio monitors, as the LS60 is too refined to be brutally honest. No, this is accuracy done right, giving you the musical picture pretty much without compromise and in an entirely enjoyable way. With all this innovation and musicality packed into two sleek and stylish speakers, who needs to be wired for sound?
A professional recording engineer since 1985, John strives for the ultimate in sound quality both in the studio and at home. With a passion for vintage equipment, as well as cutting edge technology, he has written for various British hi-fi and pro-audio magazines over the years.
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