KEF launch LSX Wireless Music System

What do you do if you’re one of the largest, most successful speaker manufacturers on the globe with one of the all-time, best-selling stereo wireless speaker designs currently in production – the LS50 Wireless at $2,199 USD – and you want to get what is already a multi-award winning product into more consumers homes?

If you’re KEF you follow up with a new design packed with the latest state-of-the-art streaming, amplification and wireless technology, make it more compact, offer five color-combos to choose from instead of three and drop the price to an expected $1,100 USD MSRP.

With more and more people I talk with looking for a truly wireless all-in-one solution for their homes – that offers real high-fidelity – KEF has seen the potential of the LS50 as a Trojan Horse of hi-fi slipping into stylish living rooms, kitchens, dining rooms and offices around the world and smartly decided that there was a huge growth potential for a smaller pair of units at a lower price point. Who knew they would basically halve the cost, but still offer all the goodies of the LS50 Wireless in a much more compact form factor, but one that still incorporates everything that made the LS50W a runaway success both critically in the hi-fi press and commercially from a sales standpoint.

The new LSX features a Uni-Q drive array consisting of a .75-inch aluminum-dome tweeter and 4.5-inch mid-bass magnesium/alloy cone that delivers a stated frequency response of 54Hz~28kHz (depending on speaker settings), smaller than the LS50’s 1-inch tweeter and 5.25-inch mid-bass units. The LSX contains four Class-D amplifiers, with each individually optimized for each of the drive units, alongside dedicated DACs which facilitate a digital signal path up to 24/96 (using the optional wired connection between the two speakers), or 24/48 in completely wireless operation. AUX and TOSLINK Optical connections are also included alongside a 3.5mm auxiliary input and an RJ45 Ethernet connection. The LSX has been "Roon tested" according to the KEF website.

Setup should be a breeze considering how easy and intuitive the KEF Control App is to use. “The app also allows LSX to receive over-the-air firmware and features updates. KEF’s optional Stream app enables use of Tidal and DLNA streaming,” according to the company.

I decided to reach out to KEF Brand Ambassador Johan Coorg with a Q&A on the LSX to get the 411 on a few things.

KEF Q&A with Johan Coorg

Rafe Arnott: Johan, what was the design precis for the LSX? What did KEF want to achieve with this new model that it hadn’t already with the highly popular and critically-acclaimed LS50 and LS50 Wireless?  

Johan Coorg: “The LS50 Wireless was developed to build on the highly successful LS50 passive credentials. With the benefit of utilization of full active DSP and bespoke internal amplification the LS50 Wireless was able to extract more performance out of the self same 5 1/4-inch Uni-Q array. Now the LSX sports a 4 1/2-inch specially developed Uni-Q also with bespoke bi-amplification. With the benefit of a simple “no mess of wires” and ancillary equipment required from a traditional hi-fi system, a (constantly evolving) “ecosystem” of software/firmware for control and streaming of music was created around the LS50 Wireless system, which is now translated to LSX through the new KEF control and stream Apps (for iOS and Android).”

RA: Obviously wireless connectivity, along with Sound Quality and user experience, is of the outmost importance to KEF for consumers with the LSX, what were some of the greatest design and engineering/tooling challenges for the LSX design/build team during R&D of the speakers?  

JC: “How to translate the successful formula into a much smaller package which retails for about half the price!”

RA: Bandwidth limitations with file sizes must have been something the engineers struggled with. Can you talk about the decision to limit the proprietary KEF wireless connection to 24/48?  

JC: “24/48 is already over CD quality. The 24-bit vs 16-bit of CD quality is the big differentiator here. More than satisfying for the practical convenience of cutting the “umbilical” between left and right channel (and not relying on a third “transmitter" box). But end-to-end 24/96 can be achieved by the LSX as it retains the possibility to connect left to right via Ethernet (CAT6 or above recommended) cable carrier. There is a “cable mode” switch on the new KEF Control app.”

RA: What does it mean in the nomenclature when KEF says the LSX “Supports source files up to 192kHz/24bit.”  

JC: “Source files of 24/192 bit are downsampled in the master speaker on LSX and transmitted either 24/48 or 24/96 depending on the inter-speaker connection mode.”

RA: Would that be accessing local files via TOSLINK or RJ45 (Network) and if the slave speaker was wired?  

JC: “Toslink is limited to 24/96 resolution anyway. Network would downsample files of resolutions higher than 24/96.”

RA: Are Tidal and Spotify Connect servers still directly feeding into the KEF App and then being forwarded via the App to the LSX over LAN via UPnP?  

JC: “Yes.”

RA: Is there a plan for a firmware upgrade to support MQA unfolding since Tidal features a growing library of thousands of MQA titles and their desktop client version supports initial unfolding to 24/96?  

JC: “Not currently on the horizon.”

RA: What about Qobuz support for your European customer base?

JC: “We are in contact with Qobuz, but currently have no plans to integrate it into the KEF Stream app. QoBuz is of course launching in USA soon and we naturally are keeping a close eye on requests from consumers Stateside. On a personal (as in European) basis, I use Qobuz and stream to LS50 Wireless and LSX using another app through which can access my Qobuz account.”

JC: “Like with LS50W, LSX has further functional possibilities via firmware updates - watch this space :-)”


  • Frequency range: (-6dB) Measured at 85dB/1m – 49Hz - 47kHz
  • Frequency response: (±3dB) Measured at 85dB/1m – 54Hz - 28kHz
  • Power input: 100 – 240VAC 50/60Hz
  • Amplifier output power Max SPL: LF: 70W HF: 30W
  • Max SPL: 102dB
  • Input resolution: Supports up to 192kHz/24bit Depending on source resolution
  • Master and Slave speaker connection: Wireless: Propriety connection 2.4GHz (transmit 48kHz/24bit) Wired: RJ45 Ethernet (transmit 96kHz/24bit)
Depending on connection settings
  • Inputs: 2.4GHz/5GHz Dual-band Wi-Fi network Bluetooth 4.2 with aptX codec TOSLINK Optical, 3.5mm Auxiliary Input, RJ45 Ethernet (For network)
  • Output: Subwoofer output 5V2A DC Output
  • Wi-Fi Network: IEEE 802.11a/b/g/n
  • Wi-Fi Network Frequency band: Dual-band 2.4GHz/ 5 GHz
  • Bluetooth range: 10m
  • Bluetooth memory: Eight device
  • Weight: 7.9 pounds
  • Dimensions: 240 x 155 x 180mm (9.5 x 6.1 x 7.1in.)

Press Release Highlights below:

KEF is proud to announce LSX, a compact two-speaker wireless music system with all the convenience and connectivity of the connected world, but with the emotion and detail of true high-resolution stereo. LSX is fully wireless both from source and between the speakers and will feature AirPlay 2 for multi-room streaming from Apple devices in January 2019.

LSX follows the award-winning LS50 Wireless, and shares much of the cutting-edge acoustic engineering that has made that product famous within the audio community. It features KEF’s Uni-Q driver array, a signature innovation that radically improves stereo imaging and does so across a much wider listening area.

This combines with KEF’s highly advanced Music Integrity EngineTM, a cutting-edge collection of bespoke Digital Signal Processing algorithms that ensure accurate time alignment and phase coherence. The result is that while LSX is small enough to sit on shelves, desktops or flank a TV, it offers a massive and deep sound field which completely belies its size. LSX’s gently curved cabinet was designed with extensive use of Finite Element Analysis and is extensively braced as well as featuring constrained layer damping as found in KEF’s high-end products. Continuing KEF’s long tradition of design collaboration, LSX was overseen by designer Michael Young who has created a masterpiece of understated elegance. LSX comes with in a choice of five colors - Black, Blue, Maroon and Olive - which are clad in a luxury fabric by Danish textile manufacturer Kvadrat – and a striking Gloss White.

LSX integrates with Spotify, Apple Music (via AirPlay 2, January 2019) and Tidal and can also access music stored on a networked hard drive or PC via DLNA. It also features Bluetooth 4.2 connectivity. Its two-box form factor make LSX perfect for music and TV, for which it features both TOSLINK optical and Auxiliary inputs.

LSX can be set-up in minutes using the KEF’s Control app which also manages feature updates via simple over-the-air downloads. With Spotify Connect built in, music lovers can stream Spotify’s entire library directly from the cloud. Streaming is never interrupted, so users can watch videos, play games, answer phone calls and more, all without causing pauses or interruptions to the music, even as the listener leaves the room or goes out of range.

Compact, effortless to operate, and with connectivity options to satisfy both music streaming and TV needs, LSX is a major step forward in the quest to deliver true and proper sound quality for connected consumers. The suggested retail price for LSX will be $1,000 and the speakers will be available through Magnolia Design Center retailers, Amazon, KEF Direct and other participating KEF Authorized Dealers.

KEF – GP Acoustics (US), Inc.
10 Timber Lane, Marlboro, New Jersey US-07746, United States
+1 732 683 23 56

nuz1's picture

I haven’t seen any mention of Roon for this product. Do you know if Roon integration is on the horizon for these speakers? Or is that just limited to the LS50s?

Rafe Arnott's picture
I've added this to the post, since according to the KEF website the LSX has been "Roon Tested."

I'd expect KEF to have the LSX Roon certified the same as the LS50 in short order. I'll reach out and try to get a firm response.

Rafe Arnott's picture
I contacted KEF and was told the following:

This from Johan Coorg via KEF PR: “FYI today I’ve set up LSX using Roon core connected to LSX via Optical digital - works great."

This from a KEF PR spokesperson:

"They're (KEF) working on it." and that "Roon endpoint coming soon (by firmware upgrade)."

"Another interesting Roon workaround for now would be to use a Google Chromecast puck powered by the USB power out on the back of the LSX and the Chromecast plugged into the aux 3.5 mm input on LSX. Very effective for native end-to-end hi-res up to 24/96. For full end-to-end benefit, use the LSX in 'Cable Mode" (between left and right units)”

Hope this helps answer any Roon-related questions.


filmfresser's picture

KEF was pretty good about Roon with the LS0W so I can't imagine that the firmware upgrade will take that long. Audiophiles have zero patience. The GCC or optical digital probably sounds just fine. A Blue pair are my Chanukah gift to myself. Sorry kids.

filmfresser's picture

KEF is going to sell a lot of these. And to non-audiophiles who don't care about the 24/96 specification. I love my LS50 W but as John Darko pointed out in his video review posted last night on DARKO, they are rather large for a desktop. The LSX are going to end up in bedrooms, kitchens (which may or not be good thing depending on how grease attaches itself to the fabric), offices, and bedrooms. Well done KEF.

Sue's picture

Could you please leave a pair of LSX wireless speakers under the tree this year? In black, of course. J don't care for the other fruit cocktail colors.

Everclear's picture

"Paint it Black"? .............. The Rolling Stones :-) ..........

Sue's picture

Apparently, the guys at Kef are not fans of The Rolling Stones. The LSX has a soft fabric finish as seen in the Darko video.

Everclear's picture

Give me a pair in "Midnight Blue" ............ Lou Gramm :-) .............

Everclear's picture

At least, LSX won't be listening to our conversations and opinions about politics :-) .........