KEF LS50 Wireless II Review: Supersonic Streaming Speakers

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The KEF LS50 Wireless II looms large in the rare world of compact, ultra-high-performance wireless speakers. With their meticulously detailed, tense and true sound – and KEF’s long history of building mini-monitors – this little web-connected stereo pair should find favor in the control rooms of streaming subscription services, online radio stations and podcasters to evaluate the quality of their signals on the net.

But I have a feeling the speakers’ most receptive audience will be well-heeled audiophiles, downsizers and clutter advocates whose appetite for sonic excellence now far exceeds the space available for heaps of hi-fi equipment and physical albums.

And while KEF speakers have a reputation for being demanding in terms of power requirements, the on-board amperage driving this show more than meets the challenge. And it should, given the first set price: $ 2,799.99 for the pair.

kef ls50 wireless ii front angled view Jonathan Takiff / IDG

Available in four color schemes, the KEF LS50 Wireless II looks cute from all angles.

Installation and operation are simple, with few (and surprisingly simple) tweaks. In Easy mode first presented to the user (there is also an Expert option revealed in KEF online user manual), the KEF Connect app simply asks you to indicate the size and reverb nature of the room where the speakers are placed, as well as where is it they will be placed in the room. The app then applies digital signal processing to adjust the bass and treble appropriately. Add a KEF subwoofer, like the mighty 10-inch, 300-watt Cube 10b ($ 750) I also auditioned and the KEF Connect app will also optimize the trio’s crossover frequency.

kef ls50 wireless ii 1 Jonathan Takiff / IDG

A KEF LS50 Wireless II and a KEF Kube 10b subwoofer paused and performed quite well above and below my antique farmhouse table. A sub can be connected to the left or right channel speaker via cable or the optional KW-1 wireless kit.

The good news is that wherever you put them down, these trendy things are sure to dress up the neighborhood. Notice the elegant two-tone face, the slim but deep dimensions of 12 x 7.9 x 12.2 inches (HxWxD), and the equally handsome rear panel with its matching door and elegantly integrated heat sink. Small but heavy at 22 pounds each, these cuties also come in a variety of color combinations to match your home’s interior décor.

Specifications, features and design notes

KEF calls its two-in-one speaker setup the Uni-Q, and it’s the secret sauce that makes its sound come together like no other. Unlike old school, space-saving two-in-one coaxial speakers where the tweeter “floats” in a separate horn-like enclosure in front of the woofer, low frequency (LF) and high frequency (HF) drivers in one. university Q arrays are fully integrated to function as a single point source. The cone of the woofer also performs the double duty of waveguide, favoring the smooth dispersion and integration of the tweeter output with dead center.

Now in its 12ns generation, Uni-Q has acquired a labyrinth-like frequency filtering system called Metamaterial Absorption Technology (MAT) which connects to the rear of the tweeter and absorbs 99% of the energy of the return wave from 600Hz and above that can cause distortion time spots.

KEF

Each part plays an important role in finishing the sound in the complex Uni-Q speaker array.

KEF installed Class D amplifiers in each speaker driving the 5.25 inch composite aluminum woofer / midrange with 280 watts of power and Class AB amplifiers to drive the 1 inch ventilated aluminum dome tweeters placed neatly in the center of the woofers.

The LS50 Wireless II are expensive, premium luxury goods that reward the discerning listener with a richly detailed sonic view of the world. With a frequency response from 45Hz to 47kHZ +/- 3dB (i.e. first add a sub!), are all you would want for music and TV sound in a living room or smaller living room, where the tight articulation of the low frequency driver and the well tempered rear door air pump they can make the bass response seem quite palpable. In a larger room, you will be happier with a connected subwoofer that adds another octave of depth to the low frequencies.

kef ls50 wireless controls ii Jonathan Takiff / IDG

A touch panel above the main speaker lights up for easy volume adjustment and source switching.

kef ls50 wireless ii app 8 Jonathan Takiff / IDG

You will need to connect the two speakers together with an ethernet cable to get the maximum resolution from streaming services like Tidal.

Suitable for speakers that deliver high frequencies only detectable by extraterrestrials (just kidding – mostly), these things can process digital files with up to 24-bit resolution and sample rates up to 348kHz via a network connection (both MQA and DSD56 files are supported), 24/96 via digital optical connection and 24/192 via digital coaxial or HDMI eARC.

Operate the speakers wirelessly connected to each other and all sources will be resampled to 24/96 PCM. Connect the speakers together with an ethernet cable and all sources will be resampled to 24/192 PCM.

You can also stream music from all popular services, including Amazon Music (which just announced support for Amazon’s HD and Ultra HD tracks today), Deezer, Qobuz, Spotify, and Tidal. The speakers also support Spotify Connect and Tidal Connect apps. There is also support for Apple AirPlay 2 and Chromecast, Other the system is Roon ready to boot. You can use Bluetooth if you wish, but support is limited to Bluetooth 4.2 and there is no support for aptX. Support for Apple Music, however, is curiously absent.

Listening test

I found the KEF LS 50 Wireless II particularly meaningful and rewarding when streaming live-cut recordings in high resolution (CD quality) and even very high resolution (SACD, DVD-Audio and Blu-Ray Audio) blessed with naturalistic voice, just elaborate and acoustic instrumentation. With eyes closed, Lin-Manuel Miranda’s original cast recording Hamilton it really put me in the “room where it happened”.

I would say the high-resolution sounds of Hiromi Uehara’s new fusion of jazz and classical Suite with silver lining increases its appeal by a good 20 percent, thanks to the immaculate 24-bit / 192kHz encoding (streamed via Qobuz) and the vivid KEF speaker depiction of his Yamaha playmates wielding violin, viola and cello. Likewise there were 24/96 streams of Donald Fagen’s two new concerts:The Nightfly: Live and the Steely Dan set Northeast Corridors – as well as a Montreux Festival brass set by Van Morrison and company attached to the 2019 Deluxe Edition of The game of healing. What a nice surprise!

kef ls50 wireless driver details ii Jonathan Takiff / IDG

KEF’s wireless remote has a range of 12 feet, if it is aimed exactly at the IR eye located under the surround of the Uni Q driver on the main speaker.

I also really enjoyed using these speakers as near-field monitors, nestled between the speakers in a flashback to my wasted youth; more appropriately with the new let it be box set that expands considerably on the album of the least produced last period of the Beatles. The LS50 Wireless II offered a fly-on-the-studio-wall listening experience, and what a journey it is to hear reduced, remixed and radically different renders of songs such as To resume, Do not let me down, And She came in through the bathroom window. (Incidentally, these juicy table scraps will also be served from Thanksgiving in a new three-part, six-hour Disney + docuseries. The Beatles: Go back, produced and directed by Peter Jackson.)

Wi-Fi Wi-Fi

The rock-solid nature of the LS50 Wireless II’s enclosures – a curved front panel made of Dough Molding Compound (polyester resin, fiberglass and calcium carbonate) and well-reinforced MDF sides – must certainly contribute to robustness and durability. speaker coloring. free service. But I suspect it is like this a less-than-stellar factor in Wi-Fi connectivity that I’ve experienced.

kef ls50 app speed test Jonathan Takiff / IDG

Wireless streaming speeds were everywhere, until I gave up and connected the LEF LS50 Wireless II directly to my router.

While Speedtest on my iPhone 12 Pro recorded Wi-Fi download speeds in my listening room at 320Mbs, the KEF Connect informational app monitored its speakers processing only 17Mbps. During the early evening hours in my neighborhood , the reception speed was reduced to just 4.9 Mbps.

It’s still good for capturing internet radio and current free / premium versions of Spotify (160Kbps / 320Kbps respectively). But that speed wasn’t enough for Tidal, and it’s half that needed to stream Qobuz in a non-stammering way.

The KEF user manual helpfully suggests keeping the router’s speakers “in line of sight” if you want to use Wi-Fi. When I tried this remedy, the speaker streaming speed increased to 36Mbps, but my router is not in the room where I go out and listen to music.

So, I ended up asking my electrician friend John Siemiarowski about Electric Magic) to run an Ethernet cable from the router to my listening room. Once wired to my network, the streaming speed of the KEFs increased up to 79 Mbps, making high-resolution streaming very happy.

Bottom line: Yes, these things can be challenging. But the best never comes cheap. And the KEF LS50 Wireless II give the best they can. Even if you can’t afford a couple now, they’re worth an instructive in-store audition. This is the stuff that home audio dreams are made of.

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