Why Kerr Acoustic's K200 Transmission Line Speaker is a Seismic Sensation

In this episode, the guys are joined on David's Hi-Fi Sofa by Jes Kerr, designer of this huge standmounting loudspeaker. Featuring very well implemented transmission line loading and three excellent and innovative drive units, this is one serious big banger!
After Jes explains the principle behind TLs, Mike waxes lyrical about hearing proper bass for the first time in a long time - well, he does have Quad electrostatics! David, meanwhile, is surveying his listening room walls for new cracks in the plaster...
Each episode of Hi-Fi Riff features Mike and David's unedited, unexpurgated views about all manner of weird and wonderful hi-fi designs. Business executive Mike has a wealth of knowledge from previous hi-fi retail experience, and David has written about hi-fi for thirty years. Now Editor-in-Chief of StereoNET, he's picked up a few things along the way.
So relax and enjoy some one-take hi-fi riffing - and please leave your comments below. And don’t forget to hit the Subscribe button, this one goes up to eleven!
The eighties-tastic title tune is called ‘UFO/Mike’s Jumper’, and used with the express permission of our old pal and rights holder Simon Lythe.
Follow Hi-Fi Riff on Instagram here: hifiriff

[@roryyoung6192]

Great to see you guys plugging these speakers guys and introducing the designer. The personal touch and it's just great to see as it brings the product alive. I'd love to hear 'Green Gartside's' voice through those speakers and I can completely relate to your music choices!

[@MrVinylista]

Thanks - you are a man of taste and distinction!

[@michaelhillmusic]

Great conversation! Loved the combo of technical deconstruction and emotional impact. I work for PMC in the states now (but in the pro audio division). Around 10 years ago I built a DIY version of the MB2's - but they didn't look anywhere near as good as these Kerr Acoustic K200's. I've always favoured the sound of transmission line speakers over ported boxes, they let the low drivers sing effortlessly. Not to mention Volt - who deserve a lot of credit for these radial drivers. Beautiful design with authoritative sonics.

[@JD-lk7im]

Well Done David, they look amazing. Really like the driver compliment. Great Riff ,once again guys. Thankyou.

[@vladimirdorta6692]

Wow! For David to do that, the speakers have to be great! And a good part of the greatness is brought by the underrated Volt midrange dome, one of the best drivers ever, IMHO.

[@hoobsgroove]

The woofer is a voit as well

[@MrVinylista]

@@hoobsgroove Twice as nice!

[@MrVinylista]

They are seriously good. Real top-tier stuff. And very much kissing cousins to my NS-1000Ms. I still prefer infinite baffle loading but these really test my loyalty to IBs!

[@hoobsgroove]

@@MrVinylista the NS1000 are they standard crossovers have they been updated? It's worth changing the pots for 36+ step attenuators with 1% smd carbon film resistors, not carbon composite. That will give your the biggest improvement.

[@MrVinylista]

@@hoobsgroove Thanks for the tip. Not sure whether to [a] keep them standard, [b] tweak them or [c] get an active crossover made!

[@stevehollingbery9744]

Usual high quality riff again, done in such a relaxed way cheers chaps. Must confess I am partial to transmission line speakers.

[@attrktmarketing4582]

It’s really great to hear the designer’s perspective. Great job Jezz. Thanks

[@bhupendraparekh6225]

Looks a great speaker, up against tough competition in atc, pmc and the ns 5000. Love that you don't need a powerhouse to drive them, thanks.

[@tonyjedioftheforest1364]

Brilliant Riff guys, one for my shopping list when I win the lottery!

[@MrVinylista]

Me too!

[@jimsregaturntableshifijukebox]

Thanks for another great riff guys 👌. Jim🏴󠁧󠁢󠁳󠁣󠁴󠁿🙂

[@paulwhite1109]

Love you two guys but what a great idea to get a designer in. Just something a bit different and very interesting.

[@gaetancharbonneau3902]

Very nice interview, super cool to hear the mastermind behind a product, a great product as it seems. Thanks guys.

[@gaetancharbonneau3902]

Simple Minds/ Big Sleep on these speakers... ouch...

[@MrVinylista]

@@gaetancharbonneau3902 Yes indeedy! Definitely up with the NS-1000M on the fun-ometer! Sledgehammer bass, super-even and integrated midband and delicious treble.

[@hamidrezahabibi8111]

I grew up 🆙 with NS-1000M. In Japan 🇯🇵, there’s an expert in NS-1000M that upgrade them and without destroying the original DNA 🧬. I truly admire KERR loudspeakers 📢

[@OysteinHasnes]

RAW speaker! Can tell as I gave heard it!

[@gdwlaw5549]

I have transmission line Jean Marie Reynaud Cantibile loudspeakers. This is the way.

[@martinscase3904]

It would be just like Mike and Dave to have someone on their channel for the first time, have him sitting between them, just to tell him his speakers are crap! Love this young guy's enthusiasm and knowledge of classic designs. I learned a lot. Brilliant video!

[@razisn]

I wasn't aware of these speakers, thank you. Ribbon tweeter, Volt drivers, as used by ProAc. I would really love to listen to these against some price competitive ProAc K-line 3-way. Only dreaming, well out of my price range. Back to listening to my ProAc D2Rs + Rel subs.

[@peterlynn3190]

Stonking riff chaps. Complemented my G&T perfectly.

[@adampoll4977]

"There's a bit of head-scratching..." Now THERE'S a modest way of talking about acoustic design ;)

[@IanKnight40]

Most sealed box designs like LS3/5A are not Infinite Baffle, they are Acoustic Suspension. The generic statement that sealed or closed box designs are Infinite Baffle is very common and not trivial in the way it affects the bass tuning of the system.

[@Soundapple]

Great guy 👍 Very cool speaker

[@christophermaley6822]

Still love my big LEAK 2075 Mk1's even now (50 years old )

[@analogueman5364]

As more than one riff raffer has commented they look remarkably like PMCs. And with an almost perfect score on the riffometer they must sound like them too. Another great riff chaps.

[@MrVinylista]

They're certainly of that ilk, but by no means identical.

[@dennistrousers1]

Shout out to Beatmasters Rock Da House, doubt they get much love these days. Obviously Age of Love too.

[@MrVinylista]

Thought it was time to show Quad electrostatic user Mike what bass sounded like! The K200s were happy to help...

[@owenoneill5955]

When David went off to get the records I was typing like a man possessed...'Don't rush, FFS don't rush'' But I was too slow 😒

[@socksumi]

Transmission line design dates back to the late 50s based on research by Radford and Bailey who co-invented and developed the mathematical models for quarter wavelength transmission line designs. Both these guys are responsible for the transmission line designs seen in iconic IMF and Radford loudspeakers.

[@jamesdyer9022]

hi guys, love your videos! Just a couple of questions, could you do a physical demo of active crossovers no diagrams! Also will a chord hugo or dave read sacd from a player like the marantz sa10?

[@audiononsense1611]

NS 1000, old school design an very British sounding... Guys, just some basic recommendations on speaker placement (this applies to anyone with a similar gear rack placed in center of speakers, no mater the height) and that is move the speaker further out into the room so that the front baffle/s are at least a foot in front of the front of the rack (this will also help with less bass boom)!!

[@MrVinylista]

NS1000Ms are very far from "British sounding', so I'm a bit mystified by your comment! As for placement, It depends on the speaker's bass loading. Infinite baffle speakers can often be used directly in front of a boundary wall, whereas with TLs it may or may not be possible. With bass reflex, you really need to be away from the rear wall unless you want some artificial bass reinforcement. As ever, use your ears to decide what works for your room.

[@Amansshed]

wimslow audio TL15 almost identical but use is the 15inch volt driver.. £6000.. These guys are simply over charging because they can

[@gijoemolinaro]

TL15 all day long and better value they make a fuss about the heat dissipation that's easily remedied just don't over power them lol

[@01sapphireGTS]

I have two pairs of Transmission Line speakers (DCM TimeFrame TF-700) and have liked them for decades. I think this technology at one point was called "folded bass".

[@MrVinylista]

Always wanted a pair of DCM Time Windows, when I was a kid - so am naturally very jealous!

[@01sapphireGTS]

@@MrVinylista I bought the first pair (used) from a local HiFi store in the mid 1990's. They were on consignment from the original owner and being offered for $400/pair. At the time, I was a huge Magnepan fan, but in no way could afford Maggies. These TF-700's got paired with an Audio Research D-100 and I really enjoyed them. Later the amp got upgraded to a Vincent SP-331 and the better the quality hardware that sat in front of these speakers, the better they sounded. I got a matching second pair with plans to either run a total of four front speakers (in "parallel" at a 4 Ohm load = 300wpc), or use the second set as speakers for my computer's 2.1 audio system.

[@johnshaw359]

Wish I had bought a pair of TDL RTL3s or better, but I wasn't aware of them at the time.

[@MrRonnmaui]

I am really curious whether the K-200 can sound "rich and full" at lower volume. Any insight on this?

[@kerracoustic3607]

Absolutely! :-) Another benefit of the low moving-mass elements within the drivers is that they remain highly responsive and linear at low input levels.

[@TriAmpHiFi]

I find the soft-dome & ribbon combo interesting. Would like to hear it.

[@MrVinylista]

@@TriAmpHiFi It's very interesting. Better still, they integrate seamlessly, when you would think they'd be doing their own thing.

[@MrVinylista]

@@kerracoustic3607 Precisely - you don't need to put lots of watts into this speaker for it to sound right, as it moves air very easily.

[@TriAmpHiFi]

@@MrVinylista Volt VM752's. About $500 each. This is why I tri-amp.... out with the horns----- in with the soft domes, easy. Can't wait. 🔈🔉🔊

[@dannyc9784]

Nice review of a cool looking speaker. I love transmission lines but with that wide front baffle do they "disappear" and image well? Also would love to know what type of crossovers are used, hopefully 1st order as they preserve the time domain.

[@tomeasterbrook9486]

Though these were PMCs at first glance?

[@MrVinylista]

Close, but no cigar!

[@RennieAsh]

I would love to see some measurements of the speaker given it's meant to be regarded as suitable for studios

[@andygee8716]

They have more than a passing resemblance to the PMC MB2 studio monitors.

[@Coneman3]

Are they Volt and scanspeak drive units? I’ve ordered similar from Wilmslow Audio.

[@TonyCottrell-iv2qv]

I like the idea of a guest but I hope this does not signal the end of the two of you gently taking the piss out of each other, that's half the fun! Speakers sound interesting, but a bit outside my price range.

[@CheekyFest]

When I think Transmission Line, I think TDL (RTL)

[@MrVinylista]

I think IMF TLS 80 and Cambridge Audio R50, from 50 years ago! Oddly, many commentators here seem to think that the only TLs ever made are PMCs, though! Nothing wrong with PMC of course, they are excellent speakers - we hope to review some soon.

[@gijoemolinaro]

Wilmslow TL15 ALL DAY LONG

[@murraywebster1228]

Would love to hear an isobaric transmission line loudspeaker….

[@MrVinylista]

Haha, now there's a thought - and arguably a contradiction in terms. Although, that said, the NEAT Majistras are arguably bass reflex isobarics, if you look at them closely.

[@n.lyndley.9889]

No contradiction there at all.

[@RennieAsh]

"I can't believe it's not PMC" K200 ;-)

[@Audfile]

Im from the states, how do I get these :(

[@gaborozorai3714]

I was expecting PMC to be mentioned as these seem to be - a bit more than superficially - a PMC with a ribbon tweeter.

[@MrVinylista]

PMC meets ATC meets IMF meets DCM!

[@dean6816]

Surely Jes can't be old enough to remember The Beatmasters??

[@chevyimp5857]

These guys are the toughest in the business when it comes to interview technique.. rigorous or what? I do like the look of them boxes mind you.. thanks for the entertainment..

[@MrVinylista]

We're not trying to be BBC-style interviewers - who ask stupid questions, are plain rude and don't let the interviewee get a word in edgeways! We really rate this speaker and wanted to share it with our viewing friends. 😊

[@jdekong3945]

😹

[@jeffkalina7727]

What was David's number? I heard 7 jokingly but... Who made the true ribbon tweeter? Thanks!

[@MrVinylista]

Jes is keeping mum about the origin of the tweeter, but it's not sourced in the UK unlike the Volt drivers. I believe the tweeter is carefully modified by Jes before being fitted to the speaker.

[@robertgough5804]

Did i miss it how much were they?

[@stevetalbot4288]

£20,000

[@mikeyevs]

Jes said it really quickly 😂

[@hoobsgroove]

Not much change out of 20,000, if you go the DIY route you can get it from 3,000 at Wilmslow audio. Well that's too pricey for you! very good model is the TL3 plus a MTM design using volt base mid-range driver TL 1,284.oo

[@user-zn2ps9gr4b]

David, Your listening room is set-up the wrong way round. You should be listening down the room. For years, we have been told that’s the right way to set-up your system. “I shouldn’t listen to anything you say anymore”, but after 20 years owning my own listing room I can confirm that all my friends and myself think putting your speakers against the long wall and sitting with you sofa about 1ft from the back wall sounded the best. I’ve been back and forth lots of times. “You made my day David”,couldn’t understand why more people don’t try it.

[@hoobsgroove]

Yeah it makes more sense if you haven't got the room less reflections combing effect from the speaker, and better still put some good thick 6 inch absorption panels Rockwall on the ends try that.

[@user-zn2ps9gr4b]

@@hoobsgroove hi hoobsgrooe. I found putting acoustic treatment on the wall behind the speakers much better, behind me the sound, sounded to rolled off and lacking dynamic. Defuse panels seemed to work better behind you.

[@a3marketing991]

Can we purchase these in the U.S.? I can't find a dealer.

[@Hi-FiRiff]

@kerracoustic3607

[@vasyapupken]

why this speakers look just like PMC MB2 ? same transmission line enclosure same woofer same dome midrange etc. it is basically an DIY version of MB2

[@MrRourk]

What is the minimum watts for these?

[@MrVinylista]

I don't know the official figure but I was able to drive them nicely with my 18 watt World Audio Design K5881 valve amp.

[@kerracoustic3607]

We would recommend having a good sturdy 20 watts or so on-hand to drive them effectively to a modest level, but beyond that it's really just down to how much dynamic headroom you require. They will happily bear the brunt of 200-watt class A/B mono's running full-tilt with uncompressed signal, should you feel the need!

[@MrRourk]

@@kerracoustic3607 Should not be a problem for my Sherwood S5500II

[@dougg1075]

I’m sorry .. did you say… 20k? Beautiful speaker

[@christophermaley6822]

Have just spotted WILMSLOW AUDIO doing virtual fully built copies of these at a MUCH, much cheaper price using expensive VOLT 12 and 15 inch units and superbly finished ???

[@MrVinylista]

Same mid & bass units, but different TL design, tweeters, cabs, crossovers, etc. - so not a 'virtual copy'.

[@christophermaley6822]

@@MrVinylista Very similar though to be honest as opposed to a virtual copy. Just shows the HUGE mark up on high end gear ?

[@MrVinylista]

@@christophermaley6822 Not necessarily very similar either - we only know that two drivers are common, there's a lot more to a speaker than that. What about the cabs, crossovers, tweeter, insulation, wiring, etc. Some high spec capacitors are £150 a pop! I don't disagree with you about the huge mark up though. You are absolutely spot on, but then we all know about high end margins. And then there's imported high end margins, another even more scary story! In this case, the truth is that Wilmslow have a different retail model. No margin for the dealer or the distributor needed, so big £££ savings. But that's a different story to claiming without evidence that these two speakers are virtually the same. I don't mean to be rude Christopher, I'm just trying to be clear that we don't claim anything we cannot back up with actual proof.

[@hoobsgroove]

They're based on the PMC studio monitor. Wilmslow audio make that TL speak a kit

[@MrVinylista]

They're not based on a PMC, they're a transmission line design that PMC uses along with others. Cabinet, driver complement, crossover, etc., are all unique.

[@hoobsgroove]

@@MrVinylista I'm not sure what's unique? They look very similar to the PCM studio monitors, got the same drivers except for not using ribbon, if there's any difference it's got to be very slight difference. possibly the crossovers could be designed in a different why, di you know the order of the crossover?

[@MrVinylista]

@@hoobsgroove Will be covering this in detail, in my forthcoming StereoNET review.

[@hoobsgroove]

@@MrVinylista ok when's that coming out?

[@MrVinylista]

@@hoobsgroove Should be 3 weeks or so. Just to be clear, the K200 utilises a brand-new Volt 250mm Radial bass driver, which is currently exclusive to the K200 - and not used in any PMC, at this time.

[@kingtubby999]

Seismic price too.... wtf! this should have been front & centre of the review, instead of this dog & pony show...and I am a fan of this channel

[@r423sdex]

Went on their web site, where are the measurements ? Basically nothing, if it's that good put them up to brag. Guess we will have to wait for Erin's audio to get some ! Really getting fed up with so called hifi companies showing absolutely nothing (NAIM, Harbeth, Audiolab, kef, b&w, rega, Exposure, etc).

[@MrVinylista]

Agree that modern speaker companies aren't very forthcoming with measured performance - but in the end it's the sound that counts and I strongly urge you to hear these, they speak for themselves - if you pardon the pun.

[@samuelsalins8309]

PMC and ATC 🤔

[@MrVinylista]

They have a new rival, it would seem.

[@nenadkojic7125]

Did I hear right? £19,995? Not real world 4 most of us....

[@MrVinylista]

Indeed, but sometimes it's good to know what you're missing!

[@eddiebaby22]

No good reviewing speakers when the makers there.

[@MrVinylista]

He wouldn't have been there if we didn't really rate the speaker anyway!

[@simonirvine1628]

Some what fairly over priced.