KEF LS50W Speakers: Why These Speakers Are Worth Every Penny


The KEF LS50W wireless speakers are a thing of beauty. I’ve seen the speakers in some higher end homes, and took note of their gorgeous lines, but hadn’t actually had the chance to hear them.  So I jumped at the chance to test the speakers out in my own home.    Sure – I know lots of studio and sound engineers – but this time it was me, and I’m not very technically oriented.

I didn’t connect the speakers correctly, and the instructions were a little complicated for someone who’s not an audiophile. But I did finally get them connected properly, after reaching out for help to Jack Sharkey, KEF’s Content Manager. I also got an unexpected lesson in physics.

The first thing I did was connect them to a 65″ television and Watch Game of Thrones in a room that is about 25′ by 20′.

The theme song sounded so incredibly amazing,  I reached out to the Game Of Thrones Live Experience PR team for tickets to Composer Ramin Djawadi’s concert in Houston Monday September 17th.  I surreptitiously filmed part of a song with my iPhone 6s. I wanted to test KEF’s claims that the LS50W’s could recreate a concert-like sound when connected to a smart phone.

I downloaded the KEF app, and connected the iPhone with bluetooth. I was a little skeptical, but when I played the video of the concert through the speakers, I was shocked. The claims are no exaggeration – it sounded like I was back in the Toyota Center with a full choir and orchestra.

The speakers are a little pricey at almost $2200.  I wanted to know how to justify that expense, and decided to compare the KEF speakers to a $200 Bose Soundlink Mini II I had been using for several years.  It’s a perfectly capable little speaker, and I thought it was great, until (thanks a lot KEF) I heard the incredible difference.

AMFM: The bluetooth connection to the phone was easy, and the app that controls it was great, but the wifi connection mode was a problem –  I thought maybe it was just me.  I easily got hold of your technical department, they emailed me right away with this reply “We noticed that you are running iOS 11.4.1. There is a known Wi-Fi issue on iOS 11.4.1. This prevents your iOS device from finding your speaker. To resolve this issue, please turn off/on Wi-Fi on your iOS device.”

Jack Sharkey: Yeah, that tends to be the nature of the beast, unfortunately. It’s one of those things where we’d love to make it as simple as we possibly can. Wi-fi is just not a mature enough technology to make it as easy as bluetooth. Everyone in the industry is trying to get to that point.

AMFM: I understand. For comparison, the other speakers I have (the Bose Mini Soundlink II and the Marley Get Up Stand Up speakers) had the same issue at first.

What happened was the KEF app said I wasn’t connected, it couldn’t find the speakers.   Actually I was connected all along – but to my phone.  So while I was trying to connect to my TV, I had been connected all along to my phone.

So that’s how I wanted to start this conversation. Even if someone is not a trained sound engineer, most people do know the quality of what they are hearing. You can throw in a lot of descriptive words like low frequency and high frequency, brightness, and the like, but when you get down to it, people just want to turn it a device on and enjoy it – they can usually hear all the sound variations even if they don’t know the names.

So if you can tell me in layman’s terms what people can expect from the KEF50W speakers, and what differentiates them from my Bose speakers.  I can hear the difference between them, but can you explain why KEF sounds so much better?


Jack: There’s a couple of subtle engineering differences that make a whole world of difference, and it goes as deep as (and I’ll try not to bore you with overly-technical details) the the type of amplifiers that we use. There are four different amplifiers. So in each box there are two different amplifiers. One for the lower frequencies and one for the higher frequencies.

AMFM: The Bi-Amp?

Jack Yes, the dual mono bi-amp. There are two mono systems and they are bi-amped. In a lower end speaker you’re going to have just one amp that handles everything from bottom to top all the way through. So that’s a big difference.

The DAC that we use, and the DSP, the Digital Signal Processor is a very high end piece. The one way that I could describe it is if you were to go and buy a Cadillac, or a Chevy Cobalt, for example,..ostensibly the same people building the car all the way through but given the opportunity to have the Cadillac or the Cobalt, which is a great little car, the Cadillac will do all that in a much better and more elegant way. That’s the analogy I use.

It’s the combination of the components we use. Even down to the power supply. We use separate power supplies to lessen or eliminate noise. It’s the cleanliness of the system. That’s what you are hearing when you listen to The Game Of Thrones. The music is there, you’ve been listening to it the whole time you’ve been listening to the show, but now you’re hearing just what the orchestra wanted you to hear, you’re not hearing any extra noise. That’s due to all the technological advances we have made. That’s the difference between listening to a $200 speaker and a $2200 speaker.

AMFM: So when I was sifting through the technical information that came with the KEF Speakers, they talked about Pre-Amp. So is that what you just talked about?

Jack I kind of did. Let’s take a walk through the system. Let’s use a turntable as an example because that helps people visualize even better.

We put the record on the turntable and put the needle down. There is an analog signal that is leaving the turntable and going into the back of the LS50W Speakers. The first thing we do is digitize that signal with an audiophile level A to D (analog to digital) converter. It’s very clean, and the clocking is very precise. This gets into a lot of wonky details that sometimes people just aren’t familiar with or interested in. But it’s that level of cleanliness that helps. We make the digital signal, and the fact that our power supply is sending a very clean signal – well you might have noticed that you have to connect the two speakers together…

AMFM: Yes.

Jack…even though it says it’s a wireless system. From a system level it is wireless, because you can attach via bluetooth or wi-fi. But we have a cable between the two speakers so we can send a digital signal as a pre-amp as it comes in from the right speaker out to the left speaker, and there are limitations on the length of that cable for clock speed in a computer system, which is really what digital music is. That clock speed has to be super, SUPER precise between the left channel and the right channel so that there is no phasing differences. Any time you introduce a phasing difference or some sort of noise to the signal, it diminishes your ability to dig on The Game Of Thrones Feed, or whatever song you happening to be listening to. By us tightening those clocks, making it super precise and high end, we eliminate all of the extraneous noise in the tracks for the listening experience.

And that incidentally is why there is a wire between our two “wireless” speakers. A lower end speaker, because they are trying to sell at a lower price point, they’re not going to put all those goodies in there. So even though it’s doing the same thing as your $200 Bose system, it’s doing that same thing way more precisely.

It’s the precision in the Digital Signal Processor and the Pre-Amp that end up exciting your ears.

Then you add the passive components, the UniQ does certain things, and the port in the back, we’re now sending an ultra clean signal to a speaker in a cabinet that knows what to do with it.

AMFM: The design of the cabinet is beautiful, but also functional. The shape, the little ridges… What is UniQ?

Jack There’s a whole bunch of things that go on with the UniQ. Number one, it’s the timing. So I’ll talk you all the way through from the center of the speaker out to the corners. What we’ve done is we have the tweeter and the mid range, the high frequency and the mid-range frequency and in the LS50 it would actually be the low frequency as well – it’s timelined.

If you can imagine you have your speakers on the three axis’s of the music. The X goes left to right, the Y goes up and down, and then the very forgotten and usually ignored z plane, which goes from front to back. If you can imagine, take a tweeter and stick it in the middle of another speaker, the sound from that tweeter is not necessarily going to leave at the same time that the sound from the mid-range leaves. So if you’re listening to say my voice speak, the low frequencies will leave at one time, but the S’s and high pitches will leave at a different time

So by the time it gets to your ear, it’s all very confused and jumbly. So what we’ve done in the over 30 years that we’ve been developing the UniQ is we’ve used computer simulations and just good old fashioned engineering work to time-align those speakers, so what is supposed to leave at the same time through both speakers does. If I can round it up for you, is to say say we’ve taken two separate individual drivers and actually made it act in air like one singular driver. So you follow that out, the ridges on the mid-range driver, depending on what color driver you have, are they blue?

AMFM: No, they’re gold.

Jack We call that Rose Gold. The ridges on the speaker, and the rubber that surrounds it has even more ridges and bumps – they are all there for a very specific reason. That is to help the high frequency sound stay in tune, or time-alignment, with the lower frequency sounds. It’s a wave guide. That wave guide helps get that sound from inside the speaker to the baffle at the box and out into the air as cleanly as possible without introducing turbulence and other reflections and difffractions and all this technical wonky stuff that actually ultimately makes…

AMFM: Physics.

Jack Yes. Physics.  And at the end of the day it’s what makes the music sound so much more clear.  And then the fun thing about the LS50W and the LS50 itself, is the curved baffle looks really cool, but that’s done for a reason as well.  If you could imagine water dripping down the side of a building or a surface. It’ll get to the bottom of the surface and make a big drop before it actually falls off.  Water wants to do the easiest thing possible – and the easiest thing is to stay attached to the surface that it’s on rather than going out into the big world. Sound acts just like water, it wants to stick to that baffle.  But when it reaches a square baffle, it bounces around, and actually acts like a second driver.

The Game Of Thrones Live Video Used To Test KEF LS50W Speakers

So now you have two speakers acting against each other, just because of the physics of the sound, and that results in “mud” and the inarticulation of the sound. What we’ve done by curving the baffle is we’ve made it a nearly infinite number of edges, because every time the sound sees a reduced edge, it goes a little bit farther. So by the time it gets to that finite, final edge of the speaker, those diffraction energies are so minimized, you just don’t hear them when they come out. That’s one of the biggest reasons that the LS50 sounds the way it sounds.


AMFM: Well, we are the voice of the artist. Could you go back a little bit in history and talk about who and why these speakers were designed?

Jack: KEF has been around since 1961, we were really involved with the BBC back in the day. We were the first company to use other components besides paper for our speakers. We were the first company to use computer analysis – this was back in the 70’s. We’ve been playing this cutting edge game for a really long time.

Ok, now I’m going to skip you forward to the end of the 2000’s before I drop you back down into the 1970’s again.

We have a full staff of accoustic engineers. Dr. Jack Oclee Brown is our head accoustic engineer, he has a doctorate in accoustics and we’ve got other engineers that have been on the team for years and years. It’s a highly qualified team that’s been with us for a while, which also makes us unique in the industry.

At the end of the 2000’s they basically and literally on a napkin started drawing up what the absolute perfect speaker shape would be in terms of those diffractions and things I just spoke about. Then that’s when “The Blade” came out. The Blade is a really awesome looking speaker, but the physical design of it is for the best possible sound response. The coolness of the look is a happy coincidence. As we move forward in time, we’re getting ready for our 50th anniversary. So back in the 70’s we had worked with the BBC on a studio monitor called the LS5A (Editor’s note: the LS5A go on ebay for around what the LS50W costs brand new)

For 25 years it was the pre-eminent studio monitor that the BBC used, and the BBC is well-renowned for it’s high quality broadcasts. So we said “For the 50th, let’s do an homage to that. Using some of the things that we learned with Blade, the curvature of the Baffles, and the port structure from some other speakers, it became the LS50. We were just going to do it as a 50th anniversary thing, thought it would be kind of cool, make it a limited product. Then it exploded on us. It’s become a really popular speaker. It just sounds so good.

AMFM: I had seen these speakers in some high-end homes, and they caught my eye because of the way they looked. But I hadn’t heard them yet. So the price of the speakers is not something that would give a person in a higher income bracket pause, but they are definitely something that someone with a good ear would appreciate.

Jack: And that’s the thing. Your first question was great – OK, how do these $2200 KEF’s compare to the $200 Bose speaker I already have? Unfortunately (in my opinion)not a lot of people are as discerning, but it would certainly enrich their lives to have a much better listening experience with great music. That’s the big difference,you hit the nail on the head…the more discerning you are the more interested you are in the actual sound, the higher end up you’re gonna go, and that’s where you’re going to derive the more ethereal benefits from the speaker.

AMFM: It’s very much like the brouhaha over analog vs. digital recording, and the richer warmer sounds that come from analog. It seems as though you guys have successfully added  rich warm sounds to digital streaming.

Jack: One of the ethos of the founder, and sort of a company mission statement, is he has a really wonderful quote.  “Of all art, music is the most indefinable and the most expressive, the most insubstantial and the most immediate, the most transitory and the most imperishable. Transformed to a dance of electrons along a wire, its ghost lives on. When KEF returns music to its rightful habituation, your ears and mind, they aim to do so in the most natural way they can… without drama, without exaggeration, without artifice.”
– Raymond Cooke, KEF founder


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