Technology

KEF LS50W Wireless Studio Monitor

Compact Active Speakers With 4 DACs, Wi-Fi, Bluetooth and App Control
The KEF LS50s offer five different inputs, including wired (RCA), Bluetooth, Wi-Fi, Optical and USB.

KEF is a multinational company that makes architectural speakers, headphones, home theater, hi-fi and “digital solutions, the category where the LS50W Wireless monitors reside. Although I’d never heard of KEF, once I got the units in for review, many of my colleagues at Blackbird Studio in Nashville not only knew of them, but cited several longtime Nashville engineers who use and love the company’s speakers.

The dual, bi-amped enclosures (30W class A/B for the tweeter and 200W class D for the mid/bass) feature the company’s Uni-Q driver—a 5.25-inch woofer with a 1-inch tweeter floating in the center (aka coaxial, though a variation). The benefits of this design are the consistent, phase-correct delivery of low- and high-frequency material to the listener and the real estate gained by not having separated drivers in the box.

The LS50W Wireless monitors debuted in October 2016 and come in Gloss White with a copper driver, Gloss Black with a Blue driver, and Titanium with a Red driver. The word wireless in the title is a bit misleading in that you can use them that way, but therare plenty of input options that cover all the bases. I used them in tracking and overdub sessions in various rooms at Blackbird and in my home.

KEF unabashedl calls the LS-50Ws an audiophile speaker. This sends up red flags for some engineers, but that’s an argument for another day with plenty of drinks. I’ve had my most moving listening experiences on audiophile systems, so to me it’s just another product description.

The IEC power socket and all the I/O are on the designated right monitor and includes: Optical (Toslink), USB type B (labeled PC), female USB type A for system upgrades, Ethernet Network input, a dedicated Ethernet output to the left speaker, RCA L/R inputs, and an RCA subwoofer output. There are small push-button EQ adjustments for Desk or Stand mountand proximity adjustments for Wall or Free Space, as well as a deep-set Reset button for returning everything to its factory setting. The monitors are also capable of Wi-Fi and Bluetooth operation. At the top of the speaker are soft-touch switches for turning them on, and toggling between the five input modes— Wi-Fi, Bluetooth, Aux (RCA), Optical and PC (USB).

The left speaker carries an IEC, a manual balance knob, and the Ethernet input used to bring audio to the speaker. The enclosures are solidly built, and the fit, finish and color options are beautiful. KEF uses “constrained layer damping bracing inside the box, with a precision-made curved baffle and elliptical, flexible sound port to re- duce turbulence and chuffing. The internal tech continues with an end-to-end 192kHz/24-bit high-resolution digital signal path using two dedicated DACs per channel (four total). The digital conversion first happens as soon as the signal arrives in the right speaker then moves to the left through the Ethernet connector. A second DAC is used post-crossover in each enclosure, allowing a more granular decode and control of the signal after DSP. Each driver is treated as a separate entity in the analog phase of the output for better quality.

For control, there is a battery-powered remote and an app, which is where Bluetooth and Wi-Fi enter the picture. Before I even heard the monitors, I downloaded the app from the Google Play store and connected my phone, Blackbird’s Wi-Fi network and the speakers. The procedure is standard fare, the same way you would set up a wireless thermostat, fan or other consumer device. Once its done, you can use the app to vary a number of great features.

At the bottom of the app’s menu screen, the Settings tab takes you to a second page, where you can send feedback, go to KEF’s website, etc., or to My Speakers. This is where you can add another set of LS50Ws or go to your system for tweaking (this only works if your speakers are on and set to Wi-Fi). The first stop under Speaker Sound Settings is a more consumer-oriented page where you designate how your speakers are set up (stand or desk), how close they are to the back wall, how large your room is in meters, and whether a sub is plugged in.

However, pros wanting more precision are going to want to choose the Expert page. Here, there are choices for engaging Desk and Wall Modeunlike the app’s consumer section  you can peel back the Wall mode (at 220 Hz) up to -6dB of attenuation in 0.5dB increments. There is also a treble trim where you can boost/cut the top end ±2dB. Next is a phase correction switch that removes phase incoherence/time smear- ing caused by the crossover, allowing the LS50W to achieve a nearly 0-degree phase shift between crossover filter outputs. If this is true, which I’m sure it is, it should be on all the time. There are choices for Bass Extension, Less, Standard or Extra. I left my system in Standard mode at all times and they worked perfectly across all my applications.

The settings grouped at the bottom of the app are all about the sub. You can set the High Pass frequency anywhere between 50 Hz and 120 Hz, set the sub outputs LP frequency anywhere between 40 Hz and 25Hz, adjust the sub’s gain plus or minus 10 dB of 0, and flip the sub’s polarity. The app is a tweaker’s paradise that you can toggle right from the listening position. The only downside is that the speakers need to be in Wi-Fi mode to use the app, meaning you can’t A/B settings immediately. This, and the lack of balanced inputs, is where the LS50s would gain from a Pro Audio version that incorporated these features.

INTO THE STUDIO

After a break-in period of many hours, my first listen was on an overdub session in Blackbird’s iconic Studio C. I set everything flat, turned off the Desk and Wall modes, and got to work. If anything, the bottom end was a bit too round, so I tempered that by putting the monitors back in Wall mode and attenuating the bottom end a dB or 2—perfect. My kick drum, pop of the snare and overheads, silky top end, and punchy mid-range sounded exactly as they did in the tracking room where I monitored on an ATC soffit-mounted system and Genelec 1031s.

The overdubs were guitars and percussion, which also sounded fan- tasticplenty of smooth top on tambourine and shakers, and punchy, cutting mids on a guitar amp recorded with a Royer 121 and SM57. When I added EQ using the channel on the SSL 9K, it sounded as I remembered on other sessions. It was a treat learning to trust the LS50Ws. I always have a time getting used to the auto-shutoff that some systems have.

The KEFs shut down after about 15 minutes, and you have to tap the controls at the top to fire them up again. A minor inconvenience you get used to in the studio. Next, I took them in to Blackbirds Studio E on top of an API 1608 where I found the first flaw. I was using a short XLR-to-RCA turnaround to get from the  console to the  KEFs, but in this room there was noticeable 60-cycle hum from the LS-50Ws when my large and alternate near-fielmonitors were chosen. This went away when the KEFs were the main speaker.

I tried ground lifting the AC plugs and even swapped to new XLR to RCA translators, but it didnt help. Being that I didnt run into this in two other rooms, I figured it was a problem between the API and the LS50W’s unbalanced inputs not playing nicely together.

During the session, it was revealing as I quickly switched between ATC SCM50As and the LS50Ws—the jump was surprisingly compara- ble. Of course the larger monitors had more bottom end, but the overall balance of frequencies, smoothness of mids and highs, and overall sonic presence in the room was so similar that it got reactions throughout the room as I switched between them.

I started using the KEFs on every session over a two-week period all with great results and then took them home to see how they fared in less than professional environments. I sent the LS50Ws audio optically from my TV and set the system up on my Wi-Fi network. They sounded fantastic. I streamed movies from Netflix and Amazon, played Apple Lossless songs over the Bluetooth connection from my phone, jumping between the two setups with the remote. It’s a beautiful high-end sys- tem for the home, where the bountiful I/O, remote control with app, and wireless options fit perfectly.

Where could they benefit? Apart from adding balanced inputs and the ability to immediately A/B using the app, I’d like to see dedicated Mode switches on the remote itself. In other words, instead of toggling blindly through the five monitoring modes with an up and down switch, it would be better to be able to jump from Optical to Wi-Fi, or other nonconsecutive settings directly with a button. For home use I would love to be able to have five LS50Ws playing back a Dolby stream from my Amazon Fire or Apple TV, but multichannel decoding is not supported, nor is Dante, which would be interesting. These added features would of course drive up the price, but the connectors are already there and it’s not a leap to think there would be interest.

The KEF LS50Ws break a lot of new ground in a unique way. First, the sound and features-to-price ratio is unheard ofthey are a true bargain. They are compact, yet the bottom end is bigger and more trustworthy than you would ever believe. If set up correctly, I’d not hesitate to make confident low end decisions—even without a sub! There is plenty of booty. And although there is room for improvement, the remote controllability is excellent. Rather than having just preset EQ functions, you can trim the levels to fine-tune your experience.

Finally, the LS50Ws sound great. It’s luxury listening in the studio and at home. So if you have the money in your budget and you’re looking for a portable, truthful monitor, you have to give the KEF LS50Ws a listen. You won’t be disappointed.


Product Summary

COMPANY: KEF
WEBSITE
: KEF.com
PRICE
: $2,199.99 (a pair)
PROS: Compact, great-sounding monitors. App control and wireless remote, abundant inputs.
CONS: Remote switching requireWi-Fi mode, no balanced inputs.

Want to read more stories like this?
Get our Free Newsletter Here!