John
How transportable is your hifi system? My latest rig flew as a single piece of checked baggage from Hong Kong to Australia and then to the UK before being couriered to Germany. Landing at my door in Berlin however, was not a pallet but a single cardboard box. Inside, a pair of standmount loudspeakers that contain dual-mono amplifiers, a D/A converter and wifi/Ethernet streamer.
We’ve seen this kind of thing before from KEF but not even their superb X300A and X300A Wireless models can compete with what we have here.
This is the loudspeaker system that I’ve been hankering for. This is the loudspeaker system that I first caught sight of during a visit to GP Acoustics’ Hong Kong HQ in August (and was asked not to film). This is the loudspeaker system formally introduced by KEF on the coattails of RMAF in October.
That’s your primer.
For this is the LS50 but not as we’ve hitherto known it. Head of R&D Jack Oclee-Brown and his team of Kent-based engineers have activated the super-popular standmount with bespoke fit amplification, DAC and network streamer and put the whole lot inside the speaker enclosures. Inside each speaker sit two amplifiers and two DACs. Digital inputs arrive at the right-hand unit with incoming digital signal upsampled to 24bit/192kHz and handed off to the left channel via Ethernet cable.
Another question: how quickly can you unbox your hifi system, wire it together and have it playing music? If it’s KEF’s LS50 Wireless system, setup goes like this: place each speaker on a speaker stand (or credenza), tie ‘em together with the (supplied) Ethernet cable, connect each speaker to a mains power socket and tap the power button on the righthand speaker’s OLED touchscreen. This 21st Century hifi system comes to life with a four-note start-up sound and we are ready to play music in under five minutes.
The fastest and easiest way to play music is the Bluetooth (4.0) input. Pair and play – anyone can do it, even your Mom. aptX-capable sources like Macbooks, (some) Windows phones and selected Android phones will deliver slightly better sound quality than those that fall back to Bluetooth audio’s more vanilla-sounding SBC: that’ll be iPhones and iPads. Presumably, KEF specified this input for convenience and inclusivity.
Most LS50 Wireless users will demand better sound quality than the Bluetooth input can provide. Let’s move on up the food chain…
A TOSLINK input means the LS50 Wireless make an ideal choice for elevating a TV’s sound quality; taking us not just to the next level but closer to the top floor. The supplied rubber feet keep them secure. This isn’t just Netflix audio elevation. Many modern Smart TVs have Spotify baked into their operating systems.
If your TV is more Plain Jane – of if you prefer Tidal or Qobuz – consider Apple’s AirPlay by setting aside the TOSLINK input for an Apple TV (3rd Gen) or an Airport Express. Alternatively, go for the best of both worlds: connect a 4th Gen Apple TV to the TV with HDMI and then the TV’s digital audio output to the LS50 Wireless’ TOSLINK socket. Easy.
Computer audiophiles – or those with more sophisticated digital audio streamers – will likely peg the LS50 Wireless’ USB input (that KEF has labelled ‘PC’) as their preferred hookup point.
Turntablists should feed their phono stage’s output into the LS50’s auxiliary input but purists should note that all incoming analogue signals are instantly digitised to 24bit/192kHz PCM; how else would the signal be split and the left channel handed over to the other loudspeaker via Ethernet?
Don’t trust the transparency of an ADC? I’d invite you to hear for yourself how even the most basic converter easily captures the differences between cartridges, surface noise and more.
Whatever your source preference, the KEF LS50 Wireless is a complete high-end audio system-in-a-box; one that thumbs its nose at the trial and error of separates compilation. Experience tells us that hooking up different amplifiers to the passive LS50 is a lottery that many audiophiles enjoy in all but expense: assuming we hit the jackpot from our first hand, amplification satisfaction will invariably take our credit cards a long way north of ~US$700 — that’s the price delta between the passive LS50 and its new active cousin.
Designing an amplifier for a passive loudspeaker where impedance swings and sensitivity vary wildly from model to model means a one size fits all approach must account for all manner of downstream unknowns.
The KEF LS50 Wireless gives us the equivalent of a dual-mono configuration but with a separate amplifier applied to each driver in KEF’s 5.25” concentric (Uni-Q) array: 200wpc of Class D for the mid/bass and 30wpc Class A/B for the tweeter. Crucially, each amplifier’s output has been tailored to the partnering driver’s impedance curve. That’s simply not possible with passive loudspeakers driven by outboard amplifiers.
Piling on another active advantage, the LS50’s Wireless crossover is stitched together via digital signal processing (DSP), thus side-stepping the potential for phase shift and/or distortion introduced by capacitors and resistors found in passive networks — like that found in the standard LS50. This DSP coding has reportedly allowed KEF to juice every last drop of performance from the LS50’s drivers, their elliptical reflex port, the curved front baffle as well as the constrained-layer damped braced cabinet in which the whole shooting match comes together.
In my listening tests, comparing the LS50 Wireless to its passive forerunner dressed in red and juiced by a Peachtree nova300 (with internal DAC) over AudioQuest Rocket 88 loudspeaker cable, the active LS50 takes Jah Wobble’s bass notes lower with more abundant textural information and renders the cymbal work found parked at the back of David Bowie’s Blackstar as altogether smoother. Voices pop with a little more clarity. Furthermore, the LS50 Wireless give us a cleaner window from which to ‘view’ inner detail and layer separation.
This Peachtree powerhouse is a superb amplifier but it’s an off-the-shelf, one size fits all solution designed to meet the needs of many varied loudspeaker designs: electrostats, planars, high efficiency widebanders, low-efficiency sealed boxes.
The LS50 Wireless are for listeners who are happy to surrender amplification flexibility in the name of superior amplifier matching with the bonus of wiping away the expense of loudspeaker cable. As a point of reference, this reviewer’s 6m pair of AudioQuest Rocket 88 speaker cable sells for around a thousand bucks!
The LS50 Wireless are therefore for listeners who demand lower physical intrusion from their hi-fi system. Also erased from the LS50 Wireless scene is the hifi rack often demanded by a passive loudspeaker system’s external components. The better-looking racks often sell for as much as the LS50 Wireless themselves: US$2199 (+ sales tax) in the USA, €2298 inclusive of VAT in Europe, £2000 inclusive of VAT in the UK.
Whether passive or active, many listeners will use speaker stands. Mine are Atacama’s Nexus 6i but if I were to place the LS50 Wireless on a sideboard or IKEA Kallax unit, I’d opt for something from Canada’s ISOAcoustics – yes, they make a big difference to sound quality even if overall aesthetics take a hit.
For even greater placement flexibility, a pair of switches on the master speaker’s rear panel allows us to DSP-tailor the LS50 Wireless’ output according to room placement: desktop or stands, free space or close to a wall. Such audible customisation recalls Dynaudio’s Xeo 2 and yet these KEFs are a far bigger sounding, more dynamic loudspeaker.
Moreover, KEF has taken room tuning to the next level – much, much further than the Danes – with a corresponding smartphone app, available for iOS and Android. Its ‘Basic’ mode applies DSP customisation according to a real-world multiple-choice Q&A: about the LS50’s location (desk or stands); about the room size; about its acoustic make-up. ‘Expert’ mode takes this DSP tweaking a step further and talks to audiophiles in terms of adding or subtracting decibels to and from the treble and lower frequencies.
Don’t worry about stuffing it up. A single button press returns us to factory default settings.
In my tests, I found different DSP settings preferable depending on placement: atop Atacama Nexus 6i stands or flanking a Samsung TV atop an IKEA Kallax unit. That makes the LS50 Wireless one of the few standmounts for which front wall proximity isn’t so much of an issue and for which, ultimately, proper stands are rendered a less essential extra.
The smartphone app is also where we integrate a subwoofer: its crossover point/s and gain – and where we turn off/on the DSP crossover phase correction (should we wish to).
These features render the KEF LS50 Wireless as ideal for people who listen in acoustically untreated spaces where listening rooms are lounge rooms or family rooms shared with others (and the TV); where loudspeakers can’t always be positioned clear of front or side walls; where a parquet floor adds a zippy liveliness to sound; where heavy furnishings might overdamp.
Sat on the couch, a slimline remote control, colour matched to the speaker’s own two-tone scheme, takes the OLED touchscreen’s functionality – input selection, volume up/down – and adds play/pause and forward/next for UPnP LAN streaming.
Those who choose to translate KEF’s ‘Wireless’ nomenclature literally will be disappointed to learn that electricity still requires cables. Will the W-word cause some customers to misperceive the active LS50 as they do the Devialet Phantom: as a fancy pair of Bluetooth speakers? The active LS50 are more front foot with vocals, better extended up top and less low slung ‘n heavy in the bass than their French rival. Not to mention a whole lot less expensive when we insist on the proper stereophony of two physically separated loudspeakers.
KEF’s ‘W’ word deployment refers to the aptX Bluetooth input but also to the WiFi LAN streaming input which, upon first use, requires the aforementioned smartphone app to hook the speakers into a wireless network. KEF call this process ‘onboarding’ where a smartphone (or tablet) temporarily connects directly and wirelessly to the LS50 Wireless in order to feed it details of our home or office’s WiFi network (SSID and password).
If that all sounds like too much hard work – or if your wifi network lacks the robustness, stability or bandwidth called for by lossless Redbook or hi-res streaming – the option to hardwire the LS50 Wireless into a network over Ethernet also presents. Got drop-outs? Go Ethernet.
At the time of writing, LAN streaming is UPnP only. Use the KEF app, or a third party app of your choice, to control playback.
Let’s exemplify: I have my music stored on a hard-drive which is USB-connected to an Intel NUC. The Intel NUC is connected to my LAN via Ethernet. Plex is my UPnP server app of choice. The NUC’s role is to serve content from its kitchen location, over the network, to the KEF LS50 Wireless’ internal streamer. The LS50 Wireless sit in the lounge room. In case it is not already obvious, there is no direct connection between the UPnP server (the Intel NUC) and the UPnP endpoint (the LS50 Wireless). Completing this digital audio streaming triangle is the smartphone app – it tells the server what to send to the speakers and when.
Alas – black mark incoming – KEF have done little to elevate my enthusiasm for UPnP streaming despite its application to less conventional servers/sources. Like several other UPnP devices out in the wild, network streaming on the LS50 Wireless isn’t gapless. It bears repeating for the less technically minded that gaplessness does not blight the KEFs’ other inputs.
End users will either find workarounds (try Bubble UPnP for Android or JRiver) or make the move to Roon via a hardware add-on. The triangular nature of network audio still applies to Roon: Roon runs on the Intel NUC as the Core (server) and sends audio over the network to a third party Roon Ready endpoint – one that’s connected directly to one of the LS50 Wireless’ digital inputs – as is instructed by the Roon smartphone/desktop app.
Roon Ready endpoints are available at different price points. Sonore microRendu (US$640) will feed the KEFs over USB. Others will prefer the financial prudence of the SonicOrbiter SE at US$299. For frugalphiles, a Gen 3 Apple TV or Airport Express provides Redbook-limited Roon Readiness but via TOSLINK for under US$100. In terms of sound quality, you get what you pay for – if you can afford it, get the microRendu. Add a linear power supply (to it) as funds allow.
Is the passive’s amplifier lottery why we hear some complain that the original LS50 are too eager in the upper mids? Or too laid back? Or that you need to spend big bucks on an amplifier to really make them sing. If nothing else, and to borrow from modern marketing parlance, this new active version allows us to the hear the LS50 as the engineers intended…and for a price that sits well below the cost of many amplifiers juicing the passive LS50 out in the field. That the LS50 Wireless additionally give us smartphone app-based DSP customisation, Bluetooth, a UPnP network streamer and D/A conversion makes them a strong contender for hi-fi bargain of the decade.
Of course, hardware upgrades here are limited to cables and loudspeaker stands. If you simply must have the flexibility of mixing n’ matching amplifiers and DACs at will, nothing stands in your way but your bank account and your willingness to jump aboard the ‘which component?’ merry-go-round.
The LS50 Wireless offer something to audiophiles and something to mainstreamers. As a straddler of worlds, the KEF standmounts walk away not only with a Knockout Award but also this publication’s Product of The Year gong for 2016. Pro-audio types and bedroom DJs have been hip to actives for decades already but cast a casual eye over any audio show or hifi store display: how many active loudspeakers do we see? One? Two if we’re lucky.
If KEF’s LS50 Wireless don’t convince audiophiles of active loudspeakers’ legitimacy, nothing will.
Postscript: If we’ve learnt anything from companies like AURALiC, OPPO Digital and Devialet, we know that streaming software evolves over time. I’d urge KEF to talk to Roon at the earliest possible opportunity. For more casual listeners, the addition of Spotify Connect wouldn’t hurt.
Further information: KEF Audio
