KEF LS50 Meta Review (Speaker)

[Vacceo]

Absolutely incredible soundstage and dynamic range (particularly noticeable with a symphony orchestra) compared to an aging (and in need of a crossover rebuild) pair of Kef 104/2s. I am seriously astonished by the LS50meta crossed over at 80Hz to subs. To the extent that my center channel speaker (Focal Chora) is being replaced by an LS50meta also. Medium size room (15*15*8 with openings on 3 corners).

It is an interesting observation, particularly on the dynamic range. The guys from Audioholics typically consider KEF as particularly lacking on that regard.

Not that I complain, as I use the active version and I'm very happy with them.

 

[pjn]

It is an interesting observation, particularly on the dynamic range. The guys from Audioholics typically consider KEF as particularly lacking on that regard.

Not that I complain, as I use the active version and I'm very happy with them.

I don't listen particularly loud - and crossing over to subs at 80Hz avoids the majority of distortion as the fairly small drivers struggle as clearly shown in Amir's review. I'm nowhere near 86db - most typically 60-65db.

 

[HarmonicTHD]

It is an interesting observation, particularly on the dynamic range. The guys from Audioholics typically consider KEF as particularly lacking on that regard.

Not that I complain, as I use the active version and I'm very happy with them.

Dynamic range is such a misused expression when it comes to subjective loudspeaker assessment - I wouldn’t give a penny what anyone says (not even Audioholics or especially not ;-))

Look at distortion vs frequency plots at different SPL levels as Amir and Erin publish. As long as your are below the distortion level you feel comfortable with at your listening habits (SPL), you are fine.

Yes of course in that regard the LS50 because of their size have limits there, but not the bigger KEFs. Plus the 50s still sound nice when not played too loud or even better with a sub, IMHO.

 

[Vacceo]

Dynamic range is such a misused expression when it comes to subjective loudspeaker assessment - I wouldn’t give a penny what anyone says (not even Audioholics or especially not ;-))

Look at distortion vs frequency plots at different SPL levels as Amir and Erin publish. As long as your are below the distortion level you feel comfortable with at your listening habits (SPL), you are fine.

Yes of course in that regard the LS50 because of their size have limits there, but not the bigger KEFs. Plus the 50s still sound nice when not played too loud or even better with a sub, IMHO.

The way I understand dynamic range is how loud it can get without distorting. Problem is, distortion can happen on a section of frequencies, several or all.

That said, what I have is the active model. I typically listen at 90db at 2 meters and in that scenario, the LS50 wireless II are more than capable of giving those SPL with a headroom of around 10 more without distortion. Sure, in a larger environment that may not be enough, but for my room, it is plenty. I also use a KC62, so the lower end is covered.

If Gene found them lacking in his home theatre room, I do not blame him. For a smaller environment, they are quite capable.

 

[HarmonicTHD]

The way I understand dynamic range is how loud it can get without distorting. Problem is, distortion can happen on a section of frequencies, several or all.

That said, what I have is the active model. I typically listen at 90db at 2 meters and in that scenario, the LS50 wireless II are more than capable of giving those SPL with a headroom of around 10 more without distortion. Sure, in a larger environment that may not be enough, but for my room, it is plenty. I also use a KC62, so the lower end is covered.

If Gene found them lacking in his home theatre room, I do not blame him. For a smaller environment, they are quite capable.

Your understanding is correct and the plots I mentioned provide you the facts. So no one has to guess what alleged “lack of dyn range” means.

The LS50 meta are certainly great (well below 1%) above some 150hz at 86dB SPL (see below). Below ca 150 Hz depends a bit on how much distortion one wants to accept especially as perception of distortion decreases with lower frequencies.

 

[Vacceo]

If distortion is noticeable above 14k Hz, it is not an issue as my hearing dissapears around that number.

If it is below 80 Hz, I don't care either as it is the subwoofer doing the heavy lifting. What applied to my passive KEF IQ's also applies (even if numbers change) to the LS50 actives.

 

[TSX]

Not that I complain, as I use the active version and I'm very happy with them.

Hi Vacceo

Do you have the LS 50 Wireless 2?

Thanks

 

[HarmonicTHD]

If distortion is noticeable above 14k Hz, it is not an issue as my hearing dissapears around that number.

If it is below 80 Hz, I don't care either as it is the subwoofer doing the heavy lifting. What applied to my passive KEF IQ's also applies (even if numbers change) to the LS50 actives.

80 hz might be a bit low cross over. Look at the plots.

Personally I would go with two subs crossed at ca 150 hz.

But please if it works for you - all good.

 

[pjn]

The way I understand dynamic range is how loud it can get without distorting. Problem is, distortion can happen on a section of frequencies, several or all.

That said, what I have is the active model. I typically listen at 90db at 2 meters and in that scenario, the LS50 wireless II are more than capable of giving those SPL with a headroom of around 10 more without distortion. Sure, in a larger environment that may not be enough, but for my room, it is plenty. I also use a KC62, so the lower end is covered.

If Gene found them lacking in his home theatre room, I do not blame him. For a smaller environment, they are quite capable.

Hmmm... I always understood dynamic range to be from the lowest to the highest volume - so for a symphony orchestra it would be from a single instrument playing, say in a concerto, to the whole orchestra. For example, Mahler's 2nd symphony, which gets quite noisy. So if the speaker can't handle the loud bits at the same setting that has the quiet bits audible, then it is limited by its dynamic range. Obviously, this will be affected by background noise which in a typical home is around 50db. Given that it is a log scale (I think?), 80 db would be 1000x louder than background and pretty noisy!

Edit - I haven't a clue how this would affect speaker cone excursion, which would, I think, be where a lot of the distortion come in.

 

[Vacceo]

80 hz might be a bit low cross over. Look at the plots.

Personally I would go with two subs crossed at ca 150 hz.

But please if it works for you - all good.

It's the active version, it digs a bit deeper than the passive.

Hi Vacceo

Do you have the LS 50 Wireless 2?

Thanks

Yeah, I do.

 

[HarmonicTHD]

Hmmm... I always understood dynamic range to be from the lowest to the highest volume - so for a symphony orchestra it would be from a single instrument playing, say in a concerto, to the whole orchestra. For example, Mahler's 2nd symphony, which gets quite noisy. So if the speaker can't handle the loud bits at the same setting that has the quiet bits audible, then it is limited by its dynamic range. Obviously, this will be affected by background noise which in a typical home is around 50db. Given that it is a log scale (I think?), 80 db would be 1000x louder than background and pretty noisy!

Edit - I haven't a clue how this would affect speaker cone excursion, which would, I think, be where a lot of the distortion come in.

Yes that is the strict definition. As said before it often gets misused in subjective reviews.

 

[McGillroy]

Listening at 90db...?! Wow!

 

[HarmonicTHD]

It's the active version, it digs a bit deeper than the passive.


Yeah, I do.

On what do you base or statement on?

Not really. Unless you consider 1Hz deeper extension significant. Still would cross them at 150Hz and with subs.
Source

A collection of loudspeakers measurements

 

[Eetu]

On what do you base or statement on?

Not really. Unless you consider 1Hz deeper extension significant. Still would cross them at 150Hz and with subs.
Source

A collection of loudspeakers measurements

You might want to check out the actual graphs. The Wireless II seems to fill in the bass 'slope' seen on so many KEF passives.

 

[pjn]

You might want to check out the actual graphs. The Wireless II seems to fill in the bass 'slope' seen on so many KEF passives.
View attachment 236959

I wonder how they do that AND avoid the distortion at lower frequencies? It is basically the same speaker but with an amplifier with custom EQ - it can't change the physics!

 

[HarmonicTHD]

You might want to check out the actual graphs. The Wireless II seems to fill in the bass 'slope' seen on so many KEF passives.
View attachment 236959

I saw that. I wasn’t sure however if it is due to the speakers, the different measurement methods (sources) or different SPL levels at which the responses were recorded. Assuming KEF applies a similar approach as with their subs and limits the driver excursion with increasing SPL (in the active version), I would expect at a certain SPL level no more significant differences between the active and the non active version, as you simply can’t cheat physics and one simply doesn’t want to overextend the mid / woofer in an coaxial driver. Admittedly I haven’t looked at the details though and might be wrong.

 

[KMO]

Yes, that bass extension will be volume dependent. I've not seen the graphs for the LS50, but I've seen ones for the LS60 showing that the bass extension starts to reduce above 85dB SPL.

(So at maximum level of 105dB, the curves would likely be the same shape).

 

[HarmonicTHD]

Yes, that bass extension will be volume dependent. I've not seen the graphs for the LS50, but I've seen ones for the LS60 showing that the bass extension starts to reduce above 85dB SPL.

(So at maximum level of 105dB, the curves would likely be the same shape).

… yes or even earlier (at lower SPL) considering that it is distorting significantly at 96dB already.

 

[Vacceo]

On what do you base or statement on?

Not really. Unless you consider 1Hz deeper extension significant. Still would cross them at 150Hz and with subs.
Source

A collection of loudspeakers measurements

I base it on KEF's baseline configuration from the app. By default, the low pass stays at 45hz. For my room, it does not work very well, so I pushed it a bit further away to 60 Hz.

Considering the environment, it sounds quite well. However, I'd still like to be able to run Dirac on them.

 

[KMO]

… yes or even earlier (at lower SPL) considering that it is distorting significantly at 96dB already.

My guess is that they know that people tend to do frequency test sweeps and calibrate at up to 85dB, which is why they chose that cut-off point (for the LS60). I think they'd try to do the same for the LS50, because...

If they were to have lower bass at calibration level than at some lower levels, you'd get over-emphasised bass in quiet passages.

(And I'm not talking about when you turn the whole thing down, where you might want some Fletcher-wotsit compensation, I mean in a track with loud 85dB bits and quieter bits, where the quiet bits aren't supposed to have extra bass).

EQ varying with volume is a real potential calibration headache, and you avoid most of it by keeping it constant up to calibration level, so it's purely an "overdrive limiter".

(Also reviewers will likely be measuring at 85dB, so you want it to look at its best for the published graphs...)