New KEF LS50 Meta

Not going to disagree at all. Like I said, take his review with a grain of salt - a big one. The mention of being less forgiving than the LS50 is a big red flag for me. But still curious nonetheless, only because of my recent experience with the R3 (which I like better than the LS50, but still doesn’t, blow me away). Probably yet another hypetrain, but time will tell.

 

This looks interesting and something I'll keep an eye on as someone who likes the ls50 / ls50 wireless, but is this Metamaterial actually new tech? It seems like the same idea as closed back headphones. Has this really never been put in a speaker before or do I just not understand? I'm skeptical of any large improvement, especially if you dial in the app settings or a good eq, but I'll for sure try to listen to it sometime.

Also it's hard to see the back panel, but I think they took away the aux input.

 

If you want to know more about the meta material stuff, you can watch their video here (around the 1:30 mark):



Basically a multi-pronged resonator (like 30 prongs all bent up to fit in a small space) with each prong or “pipe“ tuned to a different frequency, and then I think fed into another resonator or damper or something. Kills like 99% or energy above 600Hz.

They have an AES white paper as well if you want to go really deep: https://www.aes.org/tmpFiles/elib/20200928/20758.pdf

And no, you can’t deal with this in app settings or EQ - this is distortion added to the tweeter because of sound resonating from the back of the tweeter (as it moves backward) that is trapped and bounces around, eventually reflecting back again onto the tweeter causing distortion.

I can’t comment whether something like this has been used in a headphone before - perhaps someone else can comment here.

As far as the Wireless II having an analog input, yes it has one which is a 3.5mm Aux jack (I assume with a Y-cable included) - however you could easily get this info from looking at the KEF website - no need to post questions or speculations about that here, that’s just noise.

 

The new models have multiple changes (listen to the Darko interview), and it would be difficult to judge the effect of the metamaterial in isolation. Even if the effect is small, from a marketing standpoint it is understandable that KEF would hype up this particular feature. Every manufacturer always claims "improved drivers", but this is something a little more unique and distinctive they can pitch to consumers.

 

It's very likely I will be writing a review of these for The Absolute Sound.

 

You pull them out farther from the front wall than 1 meter, that's what Steve Guttenberg does when he listens in the near-field.

 

As a very good engineer once said to me, there are no bad materials, only bad APPLICATIONS of materials.

 

wow, KEF are killing it in the marketing department!

weird, normally tweeters dont have a open back. hey, this resonator thing might work. it wont turn the ls50 into anything great (basically cause physics: you cannot turn a V4 into a V8), but quite cool "tech" non the less.

 

There's an excellent interview by John Darko with of KEF about the design of the Meta technical and use of metamaterials with Jack Oclee-Brown of KEF here: https://tinyurl.com/y4f7s549

 

Hey man, this is the 3rd time in this thread this interview has been posted, including immediately above your first post above like 5 posts ago. At least read the thread before you post - it’s only 2 pages long at this point.

Also, if you’re going to announce a review of something here, it should be posted here, not promoting a potential review in TAS. Also, if you’re going to reply to multiple posts, please do it in a single reply using the multi-quote feature, rather than filling the thread with a string of noisy replies.

When in Rome and all that. Thanks.

 

I did read the thread and I missed the link to the interview.

As for multi-quote, this is the only forum that has that feature, none of the other forums I participate have this feature, so I was not aware of it. Now that I am, I will use it.

My apologies for making some simple mistakes.

 

No worries. We’re a finicky bunch around here, just trying to keep the signal to noise ratio as high as possible. Please don’t take the dislike as anything serious, just a nudge to try to stick to the forum norms. @YMO gives out dislikes like candy at Halloween. No offence intended.

 

Multi-quote is implemented in most versions of forum software. It's very likely that multi-quote is available in some or most of your forums, but the feature is often not obvious (e.g. it is unintuitive that you can hit Reply on more than one post at a time). Looking around some audio forums, I see multi-quote available in head-fi, audiophilestyle, ASR, whatsbestforum, and others.

 

Hi Metro, this information is useful, however multi-quote is not implemented either at Audio Aficioando nor AudioShark, which are the other two forums I read and post at.

Thank you for the info. Cheers.

 

This idea of a acoustic black hole is not new but kudos to KEF for making it extremely small and supposedly good efficiency with so little volume. Decent results while being cheap to manufacture and easy to assemble while providing good reason to market an upgrade.

Mini TLs and the B&W Nautilus give the same effect. You can read on diyA how it cleans up impulse response on this page and the next.

https://www.diyaudio.com/forums/full-range/268037-fast-tl-7.html

 

I don't think backwave reflection is an important problem in today's tweeters. As proof of concept, metamaterial use is commendable. Let them load the woofers with them and then we'll talk.

 

I'm not sure I understand how that works. At 4:10, if I understand it correctly, we are looking at this meta-thing from inside the driver, through the hole sound is supposed to enter this labyrinth of pipes. But the central part in the direct view is flat! It WILL reflect sound back to the driver, it is just a flat perpendicular surface. And then, maybe, some small portion of it will go to this maze and resonate.

 

The trick then would be in the way how they managed to force a driver's rear strokes to get lost in that labyrinth. If it works as intended, that's a very cool technology.

 

I'd love to know where the tweet is actually crossed. I'd guess in the range of 1200Hz to 1800Hz. Assuming a standard 12db/octave slope, its entire range is covered by the META disc. Pretty cool. Curious what the size requirements for a mid/woof META disc would be.