KEF LS50 Meta Review (Speaker)

[Newman]

That if they are used on a stand against a wall like in the picture you will have a perfectly acceptable Hi-Fi speaker covering the most of the musical audio spectrum. The measurement we see are 4 Pi, the picture shows the speakers in a 2 Pi situation. One expects at least 3dB boost around 50Hz, which lift the bass just enough to cover the low end of the most musical instruments. I can live with not hearing the occasional E1 played on a piano or double bass and certainly don't care about the C0 of an organ which is even forbidden to be played these days!

No way. Far too much bass distortion even at low-moderate volumes. I would say they are desktop or satellite speakers, as in the ‘sat’ part of sat/sub. Even then, I would prefer a sub for each speaker so I could use a relatively high roll off frequency to the subs.

Most modern music makes much use of LF energy. And Toole has IIRC mentioned that there is no need to view speakers as specialised for certain musical genres or sub-genres, for a good speaker today will certainly do all genres well. (Just in case you were about to haughtily pronounce your narrow but elite musical tastes and how little LF energy it utilises.) You shouldn’t work so hard to apologise for a speaker’s failings.

It is definitely NOT a desktop speaker. I heard the original LS50 with Arcam amplification in rooms as big as 30m2 and with the listening distance as far as 5m. No problem. In fact, I have never seen the LS50s being set up less than 3m away from the audience in all shows I have come across them.

I heard them in a smallish ‘limited numbers by booking only’ exhibition room set up by KEF themselves — in fact I had the primo seat — and they were utterly deficient in the bass.

Why so many apologists here?

 

[tecnogadget]

A great speaker haven't distortion in bass frequencies.

You are focusing on a single metric while missing the whole picture. FIY there is more than one graph in this review. The fact this speaker won’t fit every user or case scenario doesn’t rule out it is a great speaker on the rest of the metrics, designed by science parameters.
I don’t get the complaints about something that’s obvious and part of the game. You will get rising distortion at very high SPL from a small box and a midrange cone, this will happen with any similar concept speaker. Luckily there’s enough research on the audibility threshold of distortion, which is lower on the bass department than treble.
If we are playing that game then I complain for the Salon 2 (excellent measurements) for being too big, not fitting my living room and covering the sunlight from my windows.

 

[Frgirard]

Many audiophile

You are focusing on a single metric while missing the whole picture. FIY there is more than one graph in this review. The fact this speaker won’t fit every user or case scenario doesn’t rule out it is a great speaker on the rest of the metrics, designed by science parameters.
I don’t get the complaints about something that’s obvious and part of the game. You will get rising distortion at very high SPL from a small box and a midrange cone, this will happen with any similar concept speaker. Luckily there’s enough research on the audibility threshold of distortion, which is lower on the bass department than treble.
If we are playing that game then I complain for the Salon 2 (excellent measurements) for being too big, not fitting my living room and covering the sunlight from my windows.

You arrogate to yourself the right to consider your point of view as universal and deny me this right. An amateur Tyrant?

 

[Tangband]

In this case, I notice the woofer distorting, not the tweeter. Excursion is its enemy more than it is for the tweeter.

I think that you missunderstood me - the bass unit is modulating the tweeter depending on cone placement.
In Erins measurement theres only the tweeter sounding in this particular measurement. On the bass unit he has a battery, no amplifier.

And the difference in frequency response is big for the tweeter depending on where the bass cone is.

 

[tomtoo]

You are focusing on a single metric while missing the whole picture. FIY there is more than one graph in this review. The fact this speaker won’t fit every user or case scenario doesn’t rule out it is a great speaker on the rest of the metrics, designed by science parameters.
I don’t get the complaints about something that’s obvious and part of the game. You will get rising distortion at very high SPL from a small box and a midrange cone, this will happen with any similar concept speaker. Luckily there’s enough research on the audibility threshold of distortion, which is lower on the bass department than treble.
If we are playing that game then I complain for the Salon 2 (excellent measurements) for being too big, not fitting my living room and covering the sunlight from my windows.

A voice of wisdom!

Great designed speakers, just a littel low on bass capability. And everybody has to decide if its enough for himself.

 

[archerious]

Seems this just ain't going away then. Amir has explained numerous times that with room modes EQed out the sound is much more convincing. And you can clearly see in the measurements the bass is quite a bit lacking and we all know by now he takes bass very seriously.

That's a good point, bass being light is a bit annoying. Honestly might be better off going Wharfedale since I get fatigued by bright sounds (have to EQ my Arya to avoid fatigue).

John you are the best, unlike most manufacturers you actually participate in forums.

Really makes me want to buy the D90SE you designed/made.

 

[Tangband]

Thanks for the answer.
Regarding the Kef uni-q drive unit:
I looked in erins audio corner where he tested one of the uni-q drivers, Kef q100, with the cone at + 3 mm, 0 and - 3mm, with the help of a battery for the bass unit.

This simulates a variable waveguide for the centre mounted tweeter, such as you will have when you play loud bass frequencys in music .
The difference in frequency response is big . Over 8 dB difference at 7,5 khz .
When the cone moves, it will modulate the tweeter response.

Maybe thats the biggest drawback to have a tweeter mounted in the middle of a bass-unit, playing fullrange?
And maybe that will have some effect on the perceived sound quality ?

Everybody interested in Erins test , go to his site and read about the loudspeakerdriver Kef q100 . Im really suprised by the result he has found . The bass-cone is modulating the tweeter because of cone placement with a 9 volt battery ( no sound ) .

The cone of the bass unit acts as a variable waveguide for the tweeter if you play music that contains bass.

I really wonder how high you have to crossover the uni-q unit to minimize that problem ?
Is 400 Hz high enough ?

 

[Spocko]

Not really, because there's little in speakers that's less decor friendly than exposed drive units. I wish KEF had grilles for these. If they did I would buy a set and do kind of a Gradient Revolution thing with them - coax atop open baffle bass bin stands.

No doubt exposed drivers are an afterthought by speaker companies but KEF has turned this exposed driver into an iconic look by creating color contrasts with the copper metallic driver finish. Definitely not to everyone's tastes, but for me it's substantially more visually appealing than other exposed drivers.

 

[Martinvb]

Thanks @amirm, for this elaborate and spot-on review. It actually confirms my own (subjective) evaluation of the LS50 Meta's in daily use during the past months. They do not seem to need any kind of eq correction, and appear to behave quite neutral and forgiving with a wide range of musical genres and recordings. When I recently made a Digital Room Correction filter for my Volumio-driven DAC (using Brutefir) and made an A/B comparison (with/without filter) from an ideal listening position in my quite standard living room, it turned out that both conditions were hardly any different. The use of a sub is sometimes helpful, e.g. when recording quality is suboptimal and lacks energy in the lower frequencies (in my case: particularly badly produced vinyl from the 80- and 90-ties). So overall, I am very satisfied with this speaker.

 

[aarons915]

Came in here to read about measurements of the Metas as I have thought about an upgrade from the original LS50s for quite sometime now, read about crossing over at 200hz with 2 subs. Dayuuuuuuuum, looks like I need to rethink my upgrade choices. Any speaker that needs to be crossed over at 200khz with 2 subs at volume is not a speaker which I would actually go for.

You have the original LS50 so you should already know how high you need to cross them over to play as loud as you like I would think? Sometimes I get the feeling many people haven't actually measured how loud they listen to music because 85db at the listening position is extremely loud and you can see the distortion isn't that bad at the 86db @1 meter level, a 2nd order high pass in the 100-120Hz range will have them playing plenty loud with low distortion at those levels. I think the highest you would ever have to go is 150hz and only if you listen in the 90db range at your listening position. 150Hz is about the highest you can go with co-located subs before localization can be a real problem for most people also.

Everybody interested in Erins test , go to his site and read about the loudspeakerdriver Kef q100 . Im really suprised by the result he has found . The bass-cone is modulating the tweeter because of cone placement with a 9 volt battery ( no sound ) .

The cone of the bass unit acts as a variable waveguide for the tweeter if you play music that contains bass.

I really wonder how high you have to crossover the uni-q unit to minimize that problem ?
Is 400 Hz high enough ?

The 3mm excursion is the worst case scenario if you play them full range very loud, this debate is really pointless unless you don't use subs and listen at levels that cause permanent hearing damage. As I said above, crossing them at 100-120Hz is more than enough to minimize cone excursions enough where distortion is not a problem for the vast majority of people. Would I recommend a small speaker like this for Amir? Of course not but that's where we need to inject a little common sense into the discussion and know our listening levels.

How about a super LS 50 with a coaxial 6.5 inch woofer/tweeter instead.

I always thought a 6.5" would be too large to properly integrate with the tweeter in a 2-way but the Q350 shows that not to be the case so I agree and I'm not sure why they don't come out with an LS60 version. Size could be a factor, the Q350 is pretty massive for a bookshelf.

 

[Spocko]

Typical of the music industry, total disregard of standards, unlike in film production.

That is why surround in music never grow out of the niche it is in.

Unless the surround music is a "concert video" like this one from Prince mixed in Atmos and Auro3D

 

[Daverz]

It seems like the R3 would be the easy call except Erin's Audio Corner AND Amir both basically said... Measures Great! But... Meh.

I read Erin's review as much more positive about the R3. Erin tends to take more time describing flaws, so he can come off as more negative about a speaker than he really is. If Amir had a later more positive experience with them (mentioned by another poster), I missed it.

 

[dfuller]

I gotta be honest that low end distortion performance is junk for how much these cost. Why would one buy these over half a dozen different better performing speakers at this price point instead?

 

[archerious]

I gotta be honest that low end distortion performance is junk for how much these cost. Why would one buy these over half a dozen different better performing speakers at this price point instead?

What would you consider better performing at this price point? I did research and honestly don't understand. Pretty new to the objective side of music, coming from head-fi and SBAF.

 

[Spkrdctr]

I get the feeling many people haven't actually measured how loud they listen to music because 85db at the listening position is extremely loud and you can see the distortion isn't that bad at the 86db @1 meter level, a 2nd order high pass in the 100-120Hz range will have them playing plenty loud with low distortion at those levels.

Would I recommend a small speaker like this for Amir? Of course not but that's where we need to inject a little common sense into the discussion and know our listening levels.

Common sense? In an audio thread? As Pres. Biden would say "Come on man"! I put in bold your assertion that you "feel" people are not testing their listening levels. I would go further and say "almost all" and since it is probably 90% of all audio people who have not tested this for themselves you would be on safe ground. The typical scenario is that MEN ESPECIALLY will go to "check something out" in audio by cranking it up louder than they will ever listen to it. It is fun to do but not useful at all for in home listening. But my point is that holding all speakers to an extremely high unrealistic standard is kind of silly. Look at all of Amir's test data. Many speakers do pretty good at 86db with distortion. Crank it up to 96db and most all of the smaller speakers start to fall apart. The issue is, most people will use 86db once in awhile, but 96? That is really pushing things. So you have to buy based on Amir's performance data and your own personal preference. If you use a high quality decent sub, then you will not care about 80hz and below in your bookshelf speakers. So, take his excellent data and personalize it for price, performance and visual esthetics. THAT is the absolute fantastic job Amir does for everyone by doing consistent testing across the board. You can compare speakers to each other and weed out the ones that are not even close to what you need. It is like having an awesome "buyers guide" online here at ASR. Just use it by personalizing it to your needs. Need I say more?

All of you engineers and other very smart people can disregard this post. I know you guys are looking at this stuff from more of a cutting edge perspective in audio equipment performance. If the reader is not an engineer or other very knowledgeable person, Amir offers the "Buying guide" service!

 

[Spkrdctr]

I gotta be honest that low end distortion performance is junk for how much these cost. Why would one buy these over half a dozen different better performing speakers at this price point instead?

Exactly what my above post referred too. You are using the info for your personal situation. Good Work!

 

[tecnogadget]

Common sense? In an audio thread? As Pres. Biden would say "Come on man"! I put in bold your assertion that you "feel" people are not testing their listening levels. I would go further and say "almost all" and since it is probably 90% of all audio people who have not tested this for themselves you would be on safe ground. The typical scenario is that MEN ESPECIALLY will go to "check something out" in audio by cranking it up louder than they will ever listen to it. It is fun to do but not useful at all for in home listening. But my point is that holding all speakers to an extremely high unrealistic standard is kind of silly. Look at all of Amir's test data. Many speakers do pretty good at 86db with distortion. Crank it up to 96db and most all of the smaller speakers start to fall apart. The issue is, most people will use 86db once in awhile, but 96? That is really pushing things. So you have to buy based on Amir's performance data and your own personal preference. If you use a high quality decent sub, then you will not care about 80hz and below in your bookshelf speakers. So, take his excellent data and personalize it for price, performance and visual esthetics. THAT is the absolute fantastic job Amir does for everyone by doing consistent testing across the board. You can compare speakers to each other and weed out the ones that are not even close to what you need. It is like having an awesome "buyers guide" online here at ASR. Just use it by personalizing it to your needs. Need I say more?

All of you engineers and other very smart people can disregard this post. I know you guys are looking at this stuff from more of a cutting edge perspective in audio equipment performance. If the reader is not an engineer or other very knowledgeable person, Amir offers the "Buying guide" service!

Bless you both !!!

 

[phoenixdogfan]

Yeah probably not worth it. But definitely EQ! Use these settings for the og LS50 (by Maiky76):

Score after Optimization: 6.36

Type Freq Gain Q
PEQ 65.0, 3.00, 1.78,...
PEQ 166.5, -2.10, 0.88,...
PEQ 550.0, 1.40, 3.72,...
PEQ 830.0, -2.40, 1.83,...
PEQ 1224.0, -1.34, 9.45,...
PEQ 1609.0, 2.11, 2.65,...
PEQ 2764.0, -2.80, 1.35,...
PEQ 4747.0, -3.40, 3.00,...

(+ additional room correction for bass frequencies as well if you have a measurement mic)

Maybe get a sub instead if you don't have one yet?


BTW the Meta seems to have slightly wider directivity than the R3, true point source, smaller, arguably better looking, not as expensive. If you have a sub and/or don't need high SPL I'd argue it's the better option for most people.

I own both the OG's and the Metas. I was using Maiky76's eq with both, and the Metas IMHO sound much better. Far smoother. Some people will say the differences are small, but I don't perceive it that way. The OG's will go to surround duty as soon as the Octo 8 arrives at my door.

 

[phoenixdogfan]

You have the original LS50 so you should already know how high you need to cross them over to play as loud as you like I would think? Sometimes I get the feeling many people haven't actually measured how loud they listen to music because 85db at the listening position is extremely loud and you can see the distortion isn't that bad at the 86db @1 meter level, a 2nd order high pass in the 100-120Hz range will have them playing plenty loud with low distortion at those levels. I think the highest you would ever have to go is 150hz and only if you listen in the 90db range at your listening position. 150Hz is about the highest you can go with co-located subs before localization can be a real problem for most people also.



The 3mm excursion is the worst case scenario if you play them full range very loud, this debate is really pointless unless you don't use subs and listen at levels that cause permanent hearing damage. As I said above, crossing them at 100-120Hz is more than enough to minimize cone excursions enough where distortion is not a problem for the vast majority of people. Would I recommend a small speaker like this for Amir? Of course not but that's where we need to inject a little common sense into the discussion and know our listening levels.



I always thought a 6.5" would be too large to properly integrate with the tweeter in a 2-way but the Q350 shows that not to be the case so I agree and I'm not sure why they don't come out with an LS60 version. Size could be a factor, the Q350 is pretty massive for a bookshelf.

I think you can even get away with crossing them over at 100 hz with a single sub. I did that with my OG LS 50's and didn't notice any discontinuities.

 

[digitalfrost]

I gotta be honest that low end distortion performance is junk for how much these cost. Why would one buy these over half a dozen different better performing speakers at this price point instead?

Cheapest way to get your hands on one of the best coax chassis on the planet.