KEF LS50 Meta Spinorama and Measurements

[Kachda]

Measurements from Stereophile. Meta in red, original in blue. I can't help but think with the 2.5 khz bump equalized out they would be hard to tell apart.
View attachment 99801

The usp of the ls50 meta is of course the meta material reducing distortion, which I dont think is captured in stereophile measurements

 

[Ron Texas]

The usp of the ls50 meta is of course the meta material reducing distortion, which I dont think is captured in stereophile measurements

Is that measured somewhere else in this thread?

 

[thewas]

Is that measured somewhere else in this thread?

Two posts above your Stereophile comparison one, also with other comparison measurements like in room response which is similar to the Stereophile one you posted and an EQ which shows an approximation of the tonal differences.

 

[YSC]

To answer the last question first, it definitely is, below are the measurements you and I wanted to see, all from my normal loudspeaker placement so either quite early gated or MMM.

First the gated on-axis which matches the one of @napilopez well:

View attachment 99751

A MMM based listening window approximation in 50 cm from the loudspeaker which seems to be a bit more decreasing at the highs which could be also due to too large angles at my measurement:

View attachment 99752

A MMM based sound power approximation (rotating the mic the loudspeaker at 2x 360° circles), again very good match, just a similar deviation in the highs:

View attachment 99753

As to be expected than my listeners MMM matches the PIR also well except the high frequencies:

View attachment 99754

A part of the difference can be that he used the 90° orientation and calibration of his mic while I used the 0° one, although my LP MMM usually matches the ASR based one in the highs quite well.

Now to the question of the frequency response difference in the bass of the Meta vs the old Anniversary one which I also own:

View attachment 99756

Low bass seems quite identical, differences are mainly above where the Meta is much smoother, to visualise them better I computed the differences of both L, R and L+R MMM which all match well:

View attachment 99759

From those I computed the average and created manually minimal EQ for people wanting to test Meta tonality on their Anniversary ones, that is minimising their LP MMM differences:

View attachment 99760

Filter  1: ON  PK       Fc   55.30 Hz  Gain  -1.00 dB  Q  3.000
Filter  2: ON  PK       Fc   140.0 Hz  Gain  -1.00 dB  Q  2.000
Filter  3: ON  PK       Fc   450.0 Hz  Gain   1.50 dB  Q  1.400
Filter  4: ON  PK       Fc    1500 Hz  Gain   2.00 dB  Q  3.000
Filter  5: ON  PK       Fc    2600 Hz  Gain  -3.00 dB  Q  1.700

Please keep in mind that this EQ will only approximate a Meta but not make it identical to it, as both generations have slightly different crossover frequencies, slopes and thus also directivity and also different distortion behaviour but like nowdays several posted EQ settings of the Anniversary, make it sound more neutral.

Talking about distortions, the KEF paper again doesn't lie being reduced at the Meta noticeably both in the bass, mids and treble, both measured at the same, high SPL level, in absolute THD:

View attachment 99762

In relative THD:

View attachment 99763

And their components, Anniversary:

View attachment 99764

Meta, above 100 Hz the dominating component is the 2nd (3rd and above are reduced compared to the Anniversary) which is less audible and less disturbing:

View attachment 99765

Detailed listening impressions and differences I would like to post in a later point as I want to listen more to them.

it actually looks amazingly neutral above 80hz and should not sound too bass shy, placing them close to the wall near minimum port clearance seems could make it really great sounding speaker

 

[thewas]

it actually looks amazingly neutral above 80hz and should not sound too bass shy, placing them close to the wall near minimum port clearance seems could make it really great sounding speaker

I agree, in my room it has some decent bass even placed approximately 50cm from the front wall, but that was also happening to my first generation ones which are the same in the lower bass.

 

[Ron Texas]

Two posts above your Stereophile comparison one, also with other comparison measurements like in room response which is similar to the Stereophile one you posted and an EQ which shows an approximation of the tonal differences.

I'm going to play around with some of that EQ today. However, the combined effect of the room sub and a 100hz high pass filter will limit the changes to above 450hz.

 

[thewas]

I'm going to play around with some of that EQ today. However, the combined effect of the room sub and a 100hz high pass filter will limit the changes to above 450hz.

As you correctly had written anyway the biggest tonal difference is the 2,5 kHz bump of the Anniversary model.

 

[Ron Texas]

As you correctly had written anyway the biggest tonal difference is the 2,5 kHz bump of the Anniversary model.

My LS50's already had an adjustment at 2300 with a higher Q than yours. I changed it to match your list, and added adjustments at 1500 and at 450.

I can't say it makes much of a difference to me, but I am past my best years for hearing.

Because the new model has a flatter frequency response it represents an improvement over the original and makes a lot of sense from the manufacturer's point of view. As to whether it makes sense for owners of the original LS50 to upgrade, that's a much tougher question. The main limitation of a small mid/low driver is still there.

Time to listen to music.

 

[Juhazi]

My LS50's already had an adjustment at 2300 with a higher Q than yours. I changed it to match your list, and added adjustments at 1500 and at 450.

I can't say it makes much of a difference to me, but I am past my best years for hearing.

Because the new model has a flatter frequency response it represents an improvement over the original and makes a lot of sense from the manufacturer's point of view. As to whether it makes sense for owners of the original LS50 to upgrade, that's a much tougher question. The main limitation of a small mid/low driver is still there.

Time to listen to music.

Manufacturer's point of view is more publicity, higher price and extended glorification. Meta is strange, I was surprised that KEF jumped on it. But then, changing tonality and crossover to LR4 acoustic - wheres's the story?

 

[Dennis Murphy]

To answer the last question first, it definitely is, below are the measurements you and I wanted to see, all from my normal loudspeaker placement so either quite early gated or MMM.

First the gated on-axis which matches the one of @napilopez well:

View attachment 99751

A MMM based listening window approximation in 50 cm from the loudspeaker which seems to be a bit more decreasing at the highs which could be also due to too large angles at my measurement:

View attachment 99752

A MMM based sound power approximation (rotating the mic the loudspeaker at 2x 360° circles), again very good match, just a similar deviation in the highs:

View attachment 99753

As to be expected than my listeners MMM matches the PIR also well except the high frequencies:

View attachment 99754

A part of the difference can be that he used the 90° orientation and calibration of his mic while I used the 0° one, although my LP MMM usually matches the ASR based one in the highs quite well.

Now to the question of the frequency response difference in the bass of the Meta vs the old Anniversary one which I also own:

View attachment 99756

Low bass seems quite identical, differences are mainly above where the Meta is much smoother, to visualise them better I computed the differences of both L, R and L+R MMM which all match well:

View attachment 99759

From those I computed the average and created manually minimal EQ for people wanting to test Meta tonality on their Anniversary ones, that is minimising their LP MMM differences:

View attachment 99760

Filter  1: ON  PK       Fc   55.30 Hz  Gain  -1.00 dB  Q  3.000
Filter  2: ON  PK       Fc   140.0 Hz  Gain  -1.00 dB  Q  2.000
Filter  3: ON  PK       Fc   450.0 Hz  Gain   1.50 dB  Q  1.400
Filter  4: ON  PK       Fc    1500 Hz  Gain   2.00 dB  Q  3.000
Filter  5: ON  PK       Fc    2600 Hz  Gain  -3.00 dB  Q  1.700

Please keep in mind that this EQ will only approximate a Meta but not make it identical to it, as both generations have slightly different crossover frequencies, slopes and thus also directivity and also different distortion behaviour but like nowdays several posted EQ settings of the Anniversary, make it sound more neutral.

Talking about distortions, the KEF paper again doesn't lie being reduced at the Meta noticeably both in the bass, mids and treble, both measured at the same, high SPL level, in absolute THD:

View attachment 99762

In relative THD:

View attachment 99763

And their components, Anniversary:

View attachment 99764

Meta, above 100 Hz the dominating component is the 2nd (3rd and above are reduced compared to the Anniversary) which is less audible and less disturbing:

View attachment 99765

Detailed listening impressions and differences I would like to post in a later point as I want to listen more to them.

Nice. Which measurement software and mic are you using?

 

[thewas]

My LS50's already had an adjustment at 2300 with a higher Q than yours.

Yes, I also used to use steeper corrections in the past for my LS50.

I can't say it makes much of a difference to me, but I am past my best years for hearing.

If you already used an EQ I am not surprised if the differences are not significant, but please keep also in mind as I had written my EQ is just an approximation as the directivity of both is not identical.

Because the new model has a flatter frequency response it represents an improvement over the original and makes a lot of sense from the manufacturer's point of view. As to whether it makes sense for owners of the original LS50 to upgrade, that's a much tougher question. The main limitation of a small mid/low driver is still there.

For the people like us using EQ as you say possibly not (I only bought the Meta as an addition but not replacement of my Anniversary ones), but we are rather the exception in the big audio market. And yes, the LS50 Meta still isn't a loudspeaker to listen very loud, although the woofer distortion is also reduced a bit.

Manufacturer's point of view is more publicity, higher price and extended glorification.

Here in Germany the list price remained the same, same according to Stereophile in the US. I see it rather as a reference exercise/project for KEF, to take one step further maximising the sound quality performance of a compact passive 2 way speaker which I think they quite succeeded.

Nice. Which measurement software and mic are you using?

Thank you, I use REW as measurement software and as mics an ECM40 and a Sonarworks one.

 

[napilopez]

Manufacturer's point of view is more publicity, higher price and extended glorification. Meta is strange, I was surprised that KEF jumped on it. But then, changing tonality and crossover to LR4 acoustic - wheres's the story?

The way I see it, at this level of performance it is only small changes that make the difference anyway. So while I'm sure KEF wanted to keep the LS50 series popular for as long as possible, I also think they made the right upgrades.

The stock LS50 was good, but the changes to the LS50 Meta make it great (imo), if even the tweaks to get there are ultimately not that ginormous. Directivity is a bit better, and frequency response is on par with some of the studio monitors. I think if using a sub, I'd give it the edge over the R3 as well.

If the goal is to maintain the form factor -- which is imo still one of the best-looking speakers in the price bracket, I think KEF did what it needed to do. Nice to see reinforcement of the claims of lower distortion from @thewas, as well.

 

[napilopez]

I also realized I forgot to post the "squishified" measurement I often do to compare with amirs measurement aspect ratio for quick visual reference:

I referenced that to the Genelec 8030C. Which, coincidentally, has a very similar measurement profile with just more linear bass down to 60 Hz:

Considering the different measurement methods, you'd almost think these are the same speaker! Listening window and PIR, Genelec dashed:

 

[phoenixdogfan]

My LS50's already had an adjustment at 2300 with a higher Q than yours. I changed it to match your list, and added adjustments at 1500 and at 450.

I can't say it makes much of a difference to me, but I am past my best years for hearing.

Because the new model has a flatter frequency response it represents an improvement over the original and makes a lot of sense from the manufacturer's point of view. As to whether it makes sense for owners of the original LS50 to upgrade, that's a much tougher question. The main limitation of a small mid/low driver is still there.

Time to listen to music.

Maybe it makes sense if you want to use your OG LS50's as surround channels.

 

[Ron Texas]

Maybe it makes sense if you want to use your OG LS50's as surround channels.

I'm a 2 channel guy. I imagine the original LS50's would work fine as surrounds with 3 of the Meta's up front. or some R series KEF's for that matter.

 

[CJH]

Has anyone seen LS50 Meta measurements (Spinorama and EQ) with the foam plugs in place. Sub adders (like me) are very interested.
CJH

 

[thewas]

Has anyone seen LS50 Meta measurements (Spinorama and EQ) with the foam plugs in place. Sub adders (like me) are very interested.
CJH

The port is tuned around 50 Hz so it shouldn't be of relevance when correctly crossing to a subwoofer as loudspeakers like the LS50 need a higher crossover frequency to a sub. Just closing the port trying to make their bass drop earlier as an acoustic crossover is not really helpful as it won't lower the distortions in the bass region which is the main reason to use a sub with them.

 

[a-gainer]

The port is tuned around 50 Hz so it shouldn't be of relevance when correctly crossing to a subwoofer as loudspeakers like the LS50 need a higher crossover frequency to a sub. Just closing the port trying to make their bass drop earlier as an acoustic crossover is not really helpful as it won't lower the distortions in the bass region which is the main reason to use a sub with them.

+1, keep the benefits of reflex loading. Below the tuning frequency the driver is rapidly un-loading, though. That, unfiltered, would lead to excessive excursion - which is somehow mitigated by a non-linear suspension together with a quite linear motor design.

add: the foam plug would not acoustically seal the enclosure. Hence over-excursion was only gradually, if at all prevented.

 

[TonioRoffo]

I'm a 2 channel guy. I imagine the original LS50's would work fine as surrounds with 3 of the Meta's up front. or some R series KEF's for that matter.

FWIW, I'm running LS50's (original) as rears for a KEF reference frontend, with Audissey room correction, the integration is really good to my ears.

The thing with KEF is, contrary to B&W for example, that (except Q series) basically every step up in the line is just a refined version of what is below, not radically different sound/filters/drivers.

 

[CJH]

My hope is if we close off the port (since we don't need the extension plus distortion anyway), we might also get rid of the mess at 850 Hz caused by the not so perfectly designed port. Thoughts?
CJH