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New KEF LS50 collection with new Metamaterial Absorption Technology (MAT) coming.

mhardy6647

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#43
Best thing is there will be lot's of ls50's up for sale soon.
The audiophiles certainly will dump 'em like they were yardsale acquisitions from old Soundesign compact stereos -- especially if any of the reviews of the meta-KEFs include the word "jawdropping".

;)

Hifi is a fashion industry.

EDIT: In fairness, this is cool.
1600864503480.png
 
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yourmando

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#44
Never mind, I scanned the data.

I have spliced the LF of the ON to the other curves and simulated the directivity, so it's probably not perfect but a reasonable approximation.
The scores are only indicative as the resolution of the scans, although interpolated to a correct 1/20th octave resolution, is most probably too coarse.
I have done the same thing for the Kali LP8 and Presonus Eris 8XT. I'll show that at one point.

View attachment 84396
I ran my optimizer for an EQ, this just for fun... this speaker really likes a slope ( -0.215*log(f) after optimization on the LW) View attachment 84397
View attachment 84395


The regressions: there is a deliberate slope /shelf down to the response.
View attachment 84393
I guess the trough centered around 2kHz is also deliberate, BBC dip?
View attachment 84392

I then made some comparisons with the LS50 data collected by @amirm
first no EQ, there is a definite family resemblance although the new version is a major step in the correct direction.
I am eager to read the subjective reviews/comparisons, are people going to miss the "character" of the original?

View attachment 84403
View attachment 84402

Did the same thing with the LS50 EQed vs the LS50WII no EQ
View attachment 84399
Finally modified the LS50 EQ to roughly match the LS50WII and really see the improvement:
mods to the EQ:
- remove LF boost
- add Highshelf 200Hz, -3dB, Q 0.5 -> deliberate voicing?
- add Peaking 2000Hz, -1.5dB, Q 1.5 -> deliberate voicing?
if one removes what I believe are voicing choices, the EQ version of the LS50 tracks pretty well, we may be onto something ;-)
The biggest improvement seems to be coming from the tweeter section (much smoother thanks to the meta material?) and Xover with a much smoother SPDI

View attachment 84411
View attachment 84410

The new speaker looks like a significant improvement across the board.
Wow, super exciting release! This may be exactly what I’ve been looking for.

I’ve been planning on getting something small but mighty to use as elevated front heights, as well as a center channel, go go above my tower mains (and above my 133” screen). Crossed to dual subs.

@napilopez & @Maiky76 — thanks for sharing the amazing measurements and EQ insights.

The wireless version seems like a no brainer with everything built in.

Looks like 2 issues for me.

1. I need 3, but looks like they only come in pairs.
2. No XLR in. I’d love to use digital inputs, but only analog pre outs on most units. I’d have use XLR w/ pin 3 floating to rca to 3.5 mm stereo adapter. Yikes.

So looks like the wireless version is great for someone needing an all in one stereo solution. But I already have streamers, so just want the DSP, EQ, phase correction and amps like an active monitor.

As @napilopez mentioned, looks like the DI is the same for the passive meta version, so should be possible to eq close the wireless version.

Other than EQ + other correction from, say, Dirac, would there be any other limitation of the passive version vs the wireless II w/ DSP that is able to control the drivers individually?
 

asd1

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#45
The wireless version seems like a no brainer with everything built in.
I had the previous version LS50W, eventually found out it came with only 12month warranty for electronics for a reason. Lasted 2 years, needed both boards on both speakers replaced. Preferred the simpler setup, but have now gone back to passives. Keen to hear the new LS50 Meta though.
 

yourmando

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#46
I had the previous version LS50W, eventually found out it came with only 12month warranty for electronics for a reason. Lasted 2 years, needed both boards on both speakers replaced. Preferred the simpler setup, but have now gone back to passives. Keen to hear the new LS50 Meta though.
Good to know!
 

Kachda

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#47
I had the previous version LS50W, eventually found out it came with only 12month warranty for electronics for a reason. Lasted 2 years, needed both boards on both speakers replaced. Preferred the simpler setup, but have now gone back to passives. Keen to hear the new LS50 Meta though.
Funnily enough, I wanted to buy a LS50 Wireless a couple of years ago because I was tired of ruminating all the amp/speaker combos. I called a dealer nearby, and they themselves (a KEF dealer!) said they didn't recommend it because customers were having QA issues.
 
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#48
Thanks for the info :D
Right, nice graph but this is showing the closed end. Real relevant data would be to see the velocity as seen at the tweeter membrane position.

Otherwise I do not see how are all those tuned resonator are truly able to load the tweeter back cavity between
1) That perpendicular flat area (center of the "maze") offering straight reflection back to the tweeter, basically preventing loading at high frequencies.
2) The unavoidable volume/length added by the mid former tube, limiting how high the stub can be tuned.

Also, if its gain of space is a main criteria, why is this on the back of the magnet, where there is plenty of space available?
 
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jae

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#49
Never mind, I scanned the data.

I have spliced the LF of the ON to the other curves and simulated the directivity, so it's probably not perfect but a reasonable approximation.
The scores are only indicative as the resolution of the scans, although interpolated to a correct 1/20th octave resolution, is most probably too coarse.
I have done the same thing for the Kali LP8 and Presonus Eris 8XT. I'll show that at one point.

View attachment 84396
I ran my optimizer for an EQ, this just for fun... this speaker really likes a slope ( -0.215*log(f) after optimization on the LW) View attachment 84397
View attachment 84395


The regressions: there is a deliberate slope /shelf down to the response.
View attachment 84393
I guess the trough centered around 2kHz is also deliberate, BBC dip?
View attachment 84392

I then made some comparisons with the LS50 data collected by @amirm
first no EQ, there is a definite family resemblance although the new version is a major step in the correct direction.
I am eager to read the subjective reviews/comparisons, are people going to miss the "character" of the original?

View attachment 84403
View attachment 84402

Did the same thing with the LS50 EQed vs the LS50WII no EQ
View attachment 84399
Finally modified the LS50 EQ to roughly match the LS50WII and really see the improvement:
mods to the EQ:
- remove LF boost
- add Highshelf 200Hz, -3dB, Q 0.5 -> deliberate voicing?
- add Peaking 2000Hz, -1.5dB, Q 1.5 -> deliberate voicing?
if one removes what I believe are voicing choices, the EQ version of the LS50 tracks pretty well, we may be onto something ;-)
The biggest improvement seems to be coming from the tweeter section (much smoother thanks to the meta material?) and Xover with a much smoother SPDI

View attachment 84411
View attachment 84410

The new speaker looks like a significant improvement across the board.
What is the EQ'd preference score?
 

Maiky76

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#50
What is the EQ'd preference score?
Hi,

The score is in the title of the EQed Spinorama, 6.85 but again it is only an approximation.
However you can compare it with the no EQ 6.5.
 

jae

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#51
Hi,

The score is in the title of the EQed Spinorama, 6.85 but again it is only an approximation.
However you can compare it with the no EQ 6.5.
Oh I see now. Isn't that quite good in its SPL range without sub? Compared to the current measurements/list we have at this time.
 

napilopez

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#52
Thanks for the info :D
Right, nice graph but this is showing the closed end. Real relevant data would be to see the velocity as seen at the tweeter membrane position.

Otherwise I do not see how are all those tuned resonator are truly able to load the tweeter back cavity between
1) That perpendicular flat area (center of the "maze") offering straight reflection back to the tweeter, basically preventing loading at high frequencies.
2) The unavoidable volume/length added by the mid former tube, limiting how high the stub can be tuned.

Also, if its gain of space is a main criteria, why is this on the back of the magnet, where there is plenty of space available?
Did you read the whitepaper? Unless I'm misunderstanding you, the answer is right there. The graph immediately behind the tweeter dome is actually more impressive. KEF is using a waveguide and some good ol foam to 'complete' the absorption profile

Coupling the Absorber to the Tweeter Dome

The absorber sits at the rear of the Uni-Q™ driver and is coupled to the tweeter dome by a slightly tapered conical duct, which acts as a waveguide. This waveguide passes through the centre poles of both the tweeter and bass/midrange drivers and has involved a complete redesign of the tweeter magnet assembly to accommodate the wider diameter required for the duct to work properly. The difference in the motor assemblies is shown in figure 9.

A small amount of porous material is placed in the duct, which has the dual effects of reducing the amount of ripple at high frequencies and fine-tuning the knee of the absorption spectrum. Figure 10 shows the absorption spectrum immediately behind the dome.

Screenshot_20200930-011636.png
 

Juhazi

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#53
Response curves of tweeters are similar, where's the beef? Distortion?

Reasons for different response in midrange might be that 1) they want people to hear the difference and 2) adding passive RLC notches is too expensive. Active has bass boost as well.
 
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sfdoddsy

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#54
I’ve bought the LS50 three times (so far) so I obviously like it a lot.

I’ve also sold it three times (so far) so I obviously dislike it to.

The problem is not the midrange dip and subsequent boost.

I can EQ them flat as a pancake using Anthem ARC.

And the problem is not bass extension per se. I’ve EQed mine to give similar extension as the LS50W, and indeed even more.

The problem is that you need significant EQ just to get them to cross over at 80hz properly. Then even more to give them LS50W extension,

Unless you listen at lullaby levels, this is audible as distortion, compression and/or dips.

I’m sure the new LS50 will sound a bit better sans EQ than the old one.

But you’ll still need a pair of subs crossed over at 150hz or so.

I’ve mentioned it before, but I would love to see a three way LS50, ideally in the form of a small floor-stander with the UniQ at ear height and side-mounted bass drivers at floor level.

Basically a miniature Blade.
 

leonroy

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#55
But you’ll still need a pair of subs crossed over at 150hz or so.

I’ve mentioned it before, but I would love to see a three way LS50, ideally in the form of a small floor-stander with the UniQ at ear height and side-mounted bass drivers at floor level.
150Hz seems a bit high, KEF recommend 79Hz for the LS50. I will grant you though they do bottom out very quickly and sound very harsh and flat with bass heavy music at higher volumes.

The KEF Reference 1's sound to me like what the LS50s should 'sound' like, although what you're describing, a floor-stander with UniQ + two bass drivers is pretty much a Reference 3 no? That has a FR of 43Hz-35kHz +-3db vs 79Hz-+ for the LS50s.

That said, I should really check out Genelec one of these days, the specs on their 8260A are insane...
 

napilopez

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#56
Just reviving this thread to say that I received the LS50 Meta yesterday(passive only, so far). Unfortunately in black rather than the snazzy blue color, but I'll survive. Haven't unboxed them yet, but I'll be doing that later today.

I don't expect any major surprises in terms of measurements since KEF has been pretty reliable with the data in its white papers, so hopefully the spin looks like the spin there. Will be interesting to see directivity in a bit more detail though.

If anyone has any questions during testing, let me know. I'll try to A/B them with the Focal Choral 806, which is my reference speaker.
 

beagleman

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#57
A lot of the original LS-50 are being sold off.
I Think a fad occurred where many read the reviews and assumed somehow these can defy physics.

Turns out they sound really good in some ways, but are still basically a small midwoofer and all the limitations that implies on deep bass and sensitivity and power handling.

A very good speaker, for sure, but I think the reviews pushed it into something beyond what it was.
 

squall1

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#58
Just to share my experience so far...

I had a chance a couple weeks back to go and hear the passive version at a dealer that is a couple of towns over. He had a CXA81 and CXN V2 which are both components I use. He set them up in a space that I didn't think was ideal and they sounded very cold, etched, clinical. Loads of detail, but I couldn't imagine listening for more than 30 minutes. Very little upper bass as well. The dealer thought this was normal and fine though so who knows. We later went into a room that was treated well and listened to a bunch of B&W stuff that all sounded great. I should have asked him to move the Metas into that room, but it was getting late at that point and we ran out of time.

I forgot about them and then earlier this week my regular dealer responded to my earlier inquiry about them. He offered a really good price (for Taiwan) and I had a credit with him so I just decided to take a flyer despite my previous experience at the other place. Figured I could sell them on pretty easily and was honestly curious if they were really that bad or if it really was the room.

So he brought them over and I spent a little time listening yesterday. So far, tonally, they sound really nice (the dealer, my wife, and myself). Complete 180 from the other demo which my wife also heard and agreed with my take more or less. They sound balanced, but detailed, and actually on the warmer side of neutral to me. I'm playing them through a Vidar using the CX81 as a preamp and the CXN as a source. I've not had a chance to power them with the CX81. They went lower than I expected as well, again ear measurements not objective. I listened to a mix of electronic, pop, rock, singer/songwriter acoustic type stuff.

Anyway, so far so good. I heard the non-meta LS50s at another dealer awhile back, and it was good, not great to my ear. In my home, the Metas make the "sounds great" grade for us. I doubt I'll be selling them any time soon.
 

sweetchaos

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#59
Just to share my experience so far...

I had a chance a couple weeks back to go and hear the passive version at a dealer that is a couple of towns over. He had a CXA81 and CXN V2 which are both components I use. He set them up in a space that I didn't think was ideal and they sounded very cold, etched, clinical. Loads of detail, but I couldn't imagine listening for more than 30 minutes. Very little upper bass as well. The dealer thought this was normal and fine though so who knows. We later went into a room that was treated well and listened to a bunch of B&W stuff that all sounded great. I should have asked him to move the Metas into that room, but it was getting late at that point and we ran out of time.

I forgot about them and then earlier this week my regular dealer responded to my earlier inquiry about them. He offered a really good price (for Taiwan) and I had a credit with him so I just decided to take a flyer despite my previous experience at the other place. Figured I could sell them on pretty easily and was honestly curious if they were really that bad or if it really was the room.

So he brought them over and I spent a little time listening yesterday. So far, tonally, they sound really nice (the dealer, my wife, and myself). Complete 180 from the other demo which my wife also heard and agreed with my take more or less. They sound balanced, but detailed, and actually on the warmer side of neutral to me. I'm playing them through a Vidar using the CX81 as a preamp and the CXN as a source. I've not had a chance to power them with the CX81. They went lower than I expected as well, again ear measurements not objective. I listened to a mix of electronic, pop, rock, singer/songwriter acoustic type stuff.

Anyway, so far so good. I heard the non-meta LS50s at another dealer awhile back, and it was good, not great to my ear. In my home, the Metas make the "sounds great" grade for us. I doubt I'll be selling them any time soon.
Welcome to ASR and thanks for sharing your experience! :D
 

napilopez

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#60
First impressions after a few hours of listening. 100% subjective and I'm obviously I've already seen KEF's measurements, so that may be coloring my impressions. Grain of salt and all that.

But so far... man, these are sounding great.

The one thing that I can say with a fair bit of confidence is that the LS50 Meta sounds like a very different speaker to the original. Granted, I haven't heard the LS50 a couple of years, but from my recollection, this speaker sounds totally different. I'm not getting any hint of brightness. It sounds fuller and, dare I say it, a hair "warm" of neutral. I always thought the original passive LS50 sounded forward/brightish' but a little cold and slightly hollow. The LS50 Metas are sounding excellent at very low volumes too.

Even though KEF rates these the same as the original for bass extension, these seem surprisingly weighty. I mean, I'd still cross them with a sub, but I didn't find them lacking in bass the way I did the original. Granted, I have them quite near to the rear wall and have not tried the bungs yet.

I'm not trying to build more hype for these speakers and have tried to actively prevent myself from thinking that way. I mostly liked the originals, but I wasn't crazy about them, so I'm not exactly feeling nostalgia. The metamaterial is cool, but I don't know what impact it has on audible sound quality beyond the actual frequency response. Whatever the case, it seems pretty clear to me that KEF has made a significantly better speaker.

They also don't sound slightly recessed in the mids to me the way the R3 did. Slightly laid back, perhaps, but the R3 had a slight dullness as its worst bit of coloration.

I even think I'm enjoying them more than the Chora 806 that's my usual reference -- or perhaps they jive with the new space better. That's a pretty big deal -- there have been a few speakers that I know are technically better than the Choras that I haven't enjoyed as much, largely because of my preference for its extended wide directivity.

But the LS50 are imaging really well. It's possible their narrower-than-the-focals (I think!) directivity is helping negate the asymmetrical setup in my new place, or their directivity is just better. The vertical reflections will obviously be better controlled. They seem to be more stable about head movement/listening window than the Chora too.

I haven't even finished setting up my sound system and placement in my new place, so who knows. But to be fair, the speakers are currently just sitting on top of the Choras, so the different height might have something to do with it.

My impressions aside, thought I'd point out something interesting in the manual. I've previously complained that the R3 shows the speaker with toe in when KEF has told me the speakers are designed to be heard without toe-in and they measure better that way.

The LS50 Meta manual, however, specifically suggests using little to no toe-in, even for home theater.

PXL_20201016_015835027.jpg

So at the very least, this KEF speaker is designed to be heard off-axis. I'd like to think me complaining about it had something to do with the manual change, but I'm not that important :)

This is what we'd expect to be the optimal setup, given the on-axis diffraction in the spin but a much smoother listening window and front early reflections curve.

More impressions to follow -- should get a lot more listening time over the weekend.

Just to share my experience so far...

I had a chance a couple weeks back to go and hear the passive version at a dealer that is a couple of towns over. He had a CXA81 and CXN V2 which are both components I use. He set them up in a space that I didn't think was ideal and they sounded very cold, etched, clinical. Loads of detail, but I couldn't imagine listening for more than 30 minutes. Very little upper bass as well. The dealer thought this was normal and fine though so who knows. We later went into a room that was treated well and listened to a bunch of B&W stuff that all sounded great. I should have asked him to move the Metas into that room, but it was getting late at that point and we ran out of time.

I forgot about them and then earlier this week my regular dealer responded to my earlier inquiry about them. He offered a really good price (for Taiwan) and I had a credit with him so I just decided to take a flyer despite my previous experience at the other place. Figured I could sell them on pretty easily and was honestly curious if they were really that bad or if it really was the room.

So he brought them over and I spent a little time listening yesterday. So far, tonally, they sound really nice (the dealer, my wife, and myself). Complete 180 from the other demo which my wife also heard and agreed with my take more or less. They sound balanced, but detailed, and actually on the warmer side of neutral to me. I'm playing them through a Vidar using the CX81 as a preamp and the CXN as a source. I've not had a chance to power them with the CX81. They went lower than I expected as well, again ear measurements not objective. I listened to a mix of electronic, pop, rock, singer/songwriter acoustic type stuff.

Anyway, so far so good. I heard the non-meta LS50s at another dealer awhile back, and it was good, not great to my ear. In my home, the Metas make the "sounds great" grade for us. I doubt I'll be selling them any time soon.
Your latter impressions echo my thoughts a lot. I had already started typing my impressions before I saw your post, but as you see I thought much the same.
 
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