KEF LSX Wireless Speaker Aims for LS50 Performance at 1/2 the Price

KEF’s LS50 Wireless all-in-one speaker system has been hugely successful for the British loudspeaker manufacturer, and it recently took home the EISA (European Imaging and Sound Association) award for Best Wireless Loudspeaker of 2017-2018. For $2,200 per pair, the LS50 Wireless offers world-class sound from a compact package that includes a built-in network streamer, Bluetooth receiver, digital-to-analog converter, and amplifier. Now KEF is hoping to bring its wireless speaker concept to a wider audience with a miniaturized speaker system called the LSX. Like the LS50 Wireless, the LSX is a complete hi-fi system housed in two stylish bookshelf speakers. The speakers themselves are closer in size to KEF’s smaller X300A powered speakers from several years ago, but their performance and styling suggest that the LSX share a significant amount of DNA with the LS50 Wireless.

 

At $1,099 per pair, the LSX costs half as much as its bigger sibling, and its small size will appeal to style-conscious customers who don’t want an imposing loudspeaker dominating the room. Most users will connect to their home networks via the LSX’s dual-band 2.4GHz/5GHz wi-fi connection, though an ethernet input is also available. Once connected, the LSX can stream networked music via DLNA, or from Tidal, Spotify, or Roon. Support for Apple’s AirPlay2 protocol is coming in a firmware update expected to go out in January 2019, and AptX bluetooth makes it easy for friends to stream music from their phones and tablets. Wired connections include a 3.5mm analog aux input, and an optical digital input that can be used to connect a TV, game console, or disc player. Unlike the LS50 Wireless, the LSX lacks a USB input. The omission of the USB input is a bit of a disappointment; the LSX would make a fabulous pair of desktop computer speakers, and a direct USB connection is a simple solution that would allow a computer user to take advantage of the KEF speakers’ excellent built-in dac. Knowledgeable users can still make it work via wireless connectivity or the 3.5mm aux, but a USB input would have been welcome.

 

KEF LSX vs LS Wireless Speakers

The LSX does include a subwoofer output, allowing the user to add both deeper bass and more potent dynamics, should the need arise. The subwoofer connection is configured via the KEF Control app for iOS and Android, which also allows the user to tailor the sound of the LSX to match its acoustical surroundings. For example, the app will ask whether the speakers are situated on a desk or on stands, if they’re near the rear wall or out in the open, and even whether the room is acoustically damped or lively. This information is filtered through KEF’s Music Integrity Engine, which the company defines as “a cutting-edge collection of bespoke Digital Signal Processing algorithms that ensure accurate time alignment and phase coherence.” It’s a lot of tech to pack into speakers that measure just 9.5 by 6.1 by 7.1 inches. The compact cabinets, designed with extensive Finite Element Analysis, employ constrained layer damping to help dissipate unwanted vibrations. Centered on the front baffle is a smaller version of KEF’s signature Uni-Q driver array. In the LSX, a 0.75-inch aluminum dome tweeter sits inside a 4.5-inch magnesium/aluminum alloy mid-woofer (downsized from 5.25 inches in the LS50 Wireless). In each speaker, the mid-woofer is powered by its own 70-watt class D amp, while the tweeter gets 30 watts of class D power. The larger LS50 Wireless uses class AB amps for the tweeters, and high-power 200-watt class D amps for the low end, but those amps take up more space and create more heat, necessitating the addition of bulky heatsinks. KEF has made inevitable compromises to reduce costs and the size of the LSX’s cabinets, which are made of plastic rather than the MDF used in the LS50 Wireless. But the LSX also has some new tricks up its sleeve — features you won’t find on the larger and more expensive LS50 Wireless.

Wireless Considerations

The LS50 Wireless requires that an ethernet cable be used to connect the left and right speakers. Serious audiophiles may not mind; to them, the LS50 Wireless represents a streamlined replacement for a stack of components and multiple cables. But it’s not hard to imagine that some customers might expect a speaker with the word “wireless” in its name to deliver on that promise in more ways than one. Then again problems with true wireles Hi-Fi stereo connectivity plagued the KEF MUO with syncing issues so they may have felt the need to steer clear of that dilemma.  The LS50 Wireless doesn’t need a wired connection to a source, but there’s no getting around that ethernet umbilical. In the LSX, it’s a different story. KEF has developed its proprietary, wireless inter-speaker connection. Each LSX speaker needs to be plugged into a wall socket, but that’s it. This proprietary wireless connection is limited to 24-bit/48kHz, which will be fine for folks upgrading from Sonos and other mass-market wireless speakers. Audiophiles with high-res aspirations can connect two LSX speakers with an ethernet cable, increasing the resolution of the inter-speaker connection to 24-bit/96kHz, while giving up some of the sleekness of a wireless setup. The choice is yours. (For the record, the LSX can play 24/192 files, but they’ll be down sampled to 24/48 or 24/96, depending on whether you’re using the wireless link or the ethernet cable to connect the speakers.)

Audiophile with Style

Another area in which the LSX excels is in visual style. Designed by the renowned industrial designer Michael Young, the LSX is available in five colors, four of which see the cabinet clad in an industrial fabric by Danish contemporary textile designer, Kvadrat. If you don’t like the fabric look, you can choose the gloss white option, which features a silver mid-woofer cone and red tweeter. Different color options feature different accent colors in the ports and tweeters, and a color-changing LED indicates which input is in use. These thoughtful touches, together with the LSX’s smaller size, will make KEF’s newest offering more visually appealing than its predecessor.

Will the LSX be another success for KEF? Can it deliver competitive performance at this lower price? Share your thoughts in the related forum thread below. 

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