Metamaterial: a synthetic material designed from existing materials but with special attention paid to its acoustic properties. In early September, we reported on how KEF’s Kent-based engineering team were about to score a world-first by putting a metamaterial into a forthcoming loudspeaker model.
“We’ve developed a metamaterial absorber that’s a bit like an acoustic black hole – the sound goes into it and nothing comes back out,” says KEF’s Head of R&D Dr. Jack Oclee-Brown.
Today, news of two new LS50 standmount loudspeakers – the LS50 Meta and the LS50 Wireless II – advances the storyline.
Into the newly-announced and appropriately-named LS50 Meta, Oclee-Brown and his team have put Metamaterial Absorption Technology (MAT) directly behind the Uni-Q driver array’s tweeter to absorb 99% of its back wave, thus preventing any rearward firing sound from being reflected forward again by the surrounding cabinet.
From the press release: “MAT is a highly complex maze-like structure, where each of the intricate channels efficiently absorbs a range of specific frequencies. Other traditional approaches have only allowed around 60% absorption.”
For its Meta iteration, KEF has elevated the LS50’s Uni-Q driver to a 12th Generation design that sports a ‘new cone neck decoupler’ and motor system plus the ‘tweeter gap dampener’ first introduced in the 2018 R Series.
Also inside the cabinet, the LS50 Meta receives an ‘off-set flexible bass port’ designed to reduce midrange colouration and more rigid cross bracing with constrained layer damping.
The LS50 Meta will be available in four matte finishes – Carbon Black, Titanium Grey, Mineral White plus a Royal Blue Special Edition – and will sell for £1000/€1199/US$1499 per pair.
The LS50 Wireless II then activates the LS50 Meta’s 12th Generation + MAT Uni-Q driver array with a DSP crossover dividing the signal between the mid-bass driver’s new 280 Watt Class D amplifier and the tweeter’s new 100 Watt Class A/B amplifier. One upshot is 7Hz greater bass depth; the LS50 is rated by KEF down to 47Hz but the LS50 Wireless II down to 40Hz.
On hard-wired connectivity, we note two changes, one significant, the other less so: coaxial and TOSLINK remain but 1) the twin RCAs have been substituted by a 3.5mm analogue input and 2) the USB has been swapped out for HDMI ARC. KEF is likely betting that more people will put the LS50 Wireless II either side of a TV set than they will a desktop monitor. (I’ve always found the LS50 to be too much loudspeaker for a desk).
KEF has given the outmoded ‘master/slave’ terminology the boot. In its place comes ‘primary/secondary’. Whilst we’re talking language, those hanging their hat ‘Wireless’ are advised that the LS50 WII’s Ethernet-based 24bit/192kHz interlink is now optional — a 24bit/96kHz wireless interlink is also possible. And anyone pulling the LS50 Wireless II out of standby with a network stream can expect a five-second delay before the secondary speaker is woken by the primary when wirelessly interlinked.
Not mentioned in the press release: the interlink’s maximum sample rate capabilities impose a glass ceiling on listeners looking to max out the LS50 Wireless II’s hi-res streaming support: PCM up to 384kHz and DSD256. Everything streamed above the chosen interlink’s capabilities will be downsampled accordingly
The LS50 Wireless II will also support MQA in full: decoder and renderer. However, at the time of writing, it is unclear if those streams will be limited by the wired or wireless interlinks. Will MQA’s 44.1kHz/48kHz travel formats be unpacked entirely by the primary loudspeaker before being channel separated? Or will left and right channels be separated and then unpacked by their respective loudspeakers? Or will the primary speaker copy the stereo stream to the secondary speaker and then each speaker drops the channel that it doesn’t need?
That brings us to the LS50 Wireless II’s all-new streaming platform that carries with it Bluetooth (AAC but no aptX or LDAC), Apple AirPlay 2, proper Roon Readiness* (hello RAAT & multi-room sync), Spotify Connect and Google Chromecast Built-in to complete this commentator’s Holy Trinity of Streaming. Remember though: Chromecast playback isn’t gapless…
…but the LS50 Wireless II’s partnering app is. The twin KEF Control (for onboarding) and KEF Stream (for UPnP and Tidal) have been sidelined in favour of the singular KEF Connect, which handles onboarding (for those don’t wish to use the Google Home app) and integrates Tidal, Qobuz, Deezer and Amazon HD plus extensive Live Radio and Podcast directories.
Per the first generation LS50 Wireless, an EQ Settings page allows us to toggle on/off the DSP crossover’s phase accuracy, tweak its output according to the listening environment and/or loudspeaker position and integrate a subwoofer.
KEF Connect’s live search is lightning fast across all services and the user interface is uniformly smart. The now playing screen will even report on any third-party app playback. How do I know this? I’ve been playing with a pair of LS50 Wireless II for the past few weeks.
The LS50 Wireless II will be available in Carbon Black, Titanium Grey, Mineral White or a Crimson Red Special Edition for £2250/€2499/US$2499 per pair.
Every standmount loudspeaker needs a stand. Tailored to the LS50 Meta and LS50 Wireless II, KEF’s new S2 Floor Stand (£400/€450/US$449 per pair) features a top plate with secure fixing points for either new loudspeaker, a base plate to minimise vibrations plus a hollow central column that 1) can be loaded with filler (sand, kitty litter etc.) and 2) integrates cable management.
We have a short film in the works but before that comes to fruition, I invite you to go deeper – much deeper – on the new LS50 Collection via a podcast interview with Jack Oclee-Brown. Listen here.
Further information: KEF
*At time of writing, Roon is showing the LS50 Wireless II’s as uncertified.