Mis à jour le 26 February 2019.
The KEF LS50 Wireless Marcel Wanders speaker, a special edition of the KEF LS50 Wireless, is an active model with an integrated streamer and DAC. The differences are purely esthetic and include a ?nocturnal’ finish and an exclusive design from the Belgian designer Marcel Wanders on the front of the speaker. The LS50 Wireless Marcel Wanders speaker is a direct descendant of the KEF LS50, from which it sets itself apart with its four amplifiers, two DACs, streamer (Spotify, Tidal, DLNA), Bluetooth aptX receiver, and USB input allowing the speaker to be connected to a computer or TV, for example.
At most, it would be possible to add a subwoofer to this pair of connected speakers, but for the rest, there is absolutely no need for an additional hi-fi device to listen to music.
KEF LS50 Wireless: compatible audio sources
The speaker?s RCA stereo input may be used to connect a CD player, turntable (with a preamplifier) or DAP, for example. The optical input may be used to connect a UHD TV, video game console or other optical players with similar outputs. Digital signals are handled up to 192 kHz (Hi-Res Audio).
The USB-B input is intended for computers and NAS drives, as it lets the user play audio files or stream music from an online music service. The Bluetooth receiver enables wireless playback at a distance of 10m with any smartphone. The network connection (WiFi or Ethernet) widens the realm of possibilities by allowing for the playback of audio files (MP3, HD FLAC files?) stored on a smartphone or tablet, as well as those streamed from Spotify or Tidal. In this case, the KEF LS50 Wireless app (iOS and Android) must be used.
Unfortunately, the KEF app is not compatible with Qobuz or Deezer.
KEF and the single driver
KEF?s UniQ technology is the commercial name of the brand’s coaxial driver. The working principle is simple: diffuse sound toward a single point (UniQ) to prevent the convergence of several sound signals originating from multiple points of diffusion. KEF has thus developed a driver integrating a traditional cone and a tweeter working independently from each other.
The drivers found in KEF?s entry-level models are no match for the KEF LS50 Wireless Marcel Wanders? UniQ driver. While the former are good, the 5? UniQ driver is in a class of its own. And an excellent one at that.
A mark of distinction: the sensitivity of this driver is only 85 dB, which illustrates the manufacturer?s philosophy. With a rating this ?low,? KEF has obviously aimed to optimize the linearity of the drivers? frequency response throughout the entire audio spectrum. A high sensitivity rating for a driver this small (> 90 dB) would imply dominant mids and understated lows. KEF doesn’t want anything of the sort, and we find this approach very admirable.
KEF LS50 Wireless: hybrid amplification
KEF has pulled out all the stops for the LS50 Wireless speaker?s amplification. Where other manufacturers only integrate small amplifiers into their speakers, the British brand has paired up its coaxial driver with a system of bi-amplification. Better yet, the amplifiers used for each speaker implement two different technologies. The cone of the UniQ driver is paired with a Class-D amplifier capable of delivering up to 100 Watts, while the tweeter is paired with a Class-AB amplifier generating 2×30 Watts. The benefit of using a Class-D amplifier is tied to its high efficiency and its optimized damping factor: since its components range in size from small to medium, it doesn’t take up a lot of space while controlling the excursions of the UniQ driver?s cone with an iron fist. The Class-AB amplifier which drives the tweeter is not quite as efficient and sounds warmer and softer.
These amplifiers offer a number of advantages. First, since the KEF LS50 Wireless speaker is not equipped with a passive filter, the audio signal does not risk the same degradation due to electronic components as it does with the standard LS50 model. The signal is actively filtered by processors integrated into the amplifier, which allows for very steep slopes. Consequently, the tweeter boasts superior filtering of frequencies below 2.2 kHz compared to the passive model, and the energy of the restitution is boosted. In the same way, the midbass driver benefits from a better attenuation above its cutoff frequency and thus avoids encroaching on the tweeter?s territory. Lastly, the wires connecting the amplifiers to the drivers are ultra-short, thereby preserving the quality of the amplified signal.
As proof of KEF?s commitment to quality, each speaker is fitted with its own amplifier, DSP and DAC. In fact, although the two speakers are connected by a cable (Ethernet), this cable transfers a completely lossless I2S digital signal. As a result, each speaker?s sound signature is absolutely the same.
The KEF LS50 Wireless mobile app may be used to adjust the speakers? sound signature.
KEF LS50 Wireless: test conditions
While it is possible to enjoy the KEF LS50 Wireless Marcel Wanders speaker without the mobile app, using it considerably enhances the user experience. Note that the app is necessary to connect the speaker to the local WiFi network. The illustrations in the setup tutorial are very straightforward. We listened to the speaker with a smartphone running Android and CD and HD-quality FLAC files. We adjusted the EQ of the lows in order to take the characteristics of our listening room into account.
KEF LS50 Wireless: listening impressions
The driver?s low sensitivity does in fact result in a linear frequency response and an energy which is equally distributed between the three registers. The speaker offers a lively delivery and refrains from highlighting any of the registers. Indeed, the KEF LS50 Wireless Marcel Wanders know how to be serene or lively depending on what the music calls for.
Lows: well-balanced once the EQ is adjusted, without compromising the balance of the midbass. The driver?s bass-reflex port is very efficient, and lows are tight and never trail. A surprising amount of punch given the compact size of the transducer.
Mids: detailed and balanced in the midbass, with a slight coloration. Overall, linear and responsive.
Highs: precise, yet a bit dry at times
KEF LS50 Wireless: compared to?
Devialet Phantom Silver/Gold (pair): the KEF LS50 Wireless speakers offer better balance, better rhythm and more enthusiasm, in addition to a more thorough exploration of the upper lows for a truly enjoyable listening experience. Devialet takes the lead in terms of streaming services and extravagant design.
Electrocompaniet SL-1/L-1: the Electrocompaniet speakers offer a sophisticated and warm restitution, which makes them comparable to the KEF LS50 Wireless. The soundstage is nonetheless wider with the KEF, which dole out more energy.
Elipson Prestige Facet 6BT: the Elipson speaker benefits from a very bright and flattering tweeter which, in addition to its much more attractive price tag, makes the French speaker an attractive choice. However, the KEF LS50 takes the lead for the quality of its amplification, functionality, tonal balance, timing, and streaming functions.
Naim mu-so : is drawing a comparison appropriate? It?s difficult, if not impossible, for a sole speaker, even if it is a stereo model, to compete with two speakers spaced several feet apart. Clearly, the KEF LS50 Wireless win out for their more expressive sound restitution, which is more enjoyable at high volume levels.
With their optimized, integrated amplification and efficient tonal correction, the KEF LS50 Wireless Marcel Wanders speakers are an unquestionable success. Analytical yet warm, they aim to please those looking for a compact, all-in-one hi-fi solution to listen to music and movies with a high level of detail.
What we liked:
- The analog and digital connections
- The streaming functions
- The wide soundstage and the centered voices (excellent attention to phase)
- The dual band WiFi and cabled Ethernet connection
What we would have liked:
- Chromecast Built-in
- Broader support for streaming services