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New KEF speaker?

dogmamann

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I wonder if that tweeter will still have the godawful resonance over 25kHz that other current Uni-Q's seem to have? We may not be able to hear it, but I'm wondering more and more if its effects can be heard lower down, especially with so called 'hi-res' sources with lots of noise (shaping) going on...
The resonance is present even in the meta based drivers- I never understood what exactly is resonance whihc they fixed with the meta.
 

Penelinfi

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The resonance is present even in the meta based drivers- I never understood what exactly is resonance whihc they fixed with the meta.
The meta "absorbs" reflected soundwaves from the rear side of the tweeter , afaik by using many resonant pathways which cancel specific frequencies. Overall effect is a reduction of sound travelling back up through the diaphragm.

As opposed to using a chamber filled with some damping material.
 

dogmamann

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The meta "absorbs" reflected soundwaves from the rear side of the tweeter , afaik by using many resonant pathways which cancel specific frequencies. Overall effect is a reduction of sound travelling back up through the diaphragm.

As opposed to using a chamber filled with some damping material.
I read that in their website. But what I am trying to understand is, which part of the old speakers measurement shows these resonances ?! It would be great if someone can point them in some measurements with a comparison of the same part in meta it would have been great.
 

thewas

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The resonance is present even in the meta based drivers- I never understood what exactly is resonance whihc they fixed with the meta.
These are two different things, the breakup mode of every hard dome at some frequency that is hopefully higher than the audio band and the damping of the rear radiated sound which would be probably more seen in the time response/decay.
 

dogmamann

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These are two different things, the breakup mode of every hard dome at some frequency that is hopefully higher than the audio band and the damping of the rear radiated sound which would be probably more seen in the time response/decay.
Is the decay difference audible? For example if a tweeter produces 8000 hz for 1 second, and then stops, decay here means the time the tweeter takes to rest after the signal is stopped right ? But thats the case, is “timing” of drivers really a thing?

If that’s the case which metric shows the difference meta brought?

In the case of KEF, such a solution was needed only because of their specific location of the tweeter which leaves very little space to have enough damping material.
 

thewas

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Is the decay difference audible? For example if a tweeter produces 8000 hz for 1 second, and then stops, decay here means the time the tweeter takes to rest after the signal is stopped right ? But thats the case, is “timing” of drivers really a thing?

If that’s the case which metric shows the difference meta brought?

In the case of KEF, such a solution was needed only because of their specific location of the tweeter which leaves very little space to have enough damping material.
It was not as much as space issue as they could have used also a large tapered tube like for example B&W but with the meta absorber they also reach very high absorption rates which are higher than with typical damping material:

1697715887208.png


The Meta generation tweeter has generally lower distortion compared to the previous generation

1697716108931.png


but its not just due to the Meta absorber but also due to other improvements which are all described in the corresponding white papers like https://www.audiosciencereview.com/forum/index.php?threads/kef-r-series-with-mat-white-paper.43946/ from which also above these 2 plots are taken.

How much each individual of these improvements contribute to what is something you can only ask the KEF engineers who participate here.
Audibility of those is even a harder topic which in the current state of research doesn't have a black & white answer as it depends also on so many other factors.
 

dogmamann

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It was not as much as space issue as they could have used also a large tapered tube like for example B&W but with the meta absorber they also reach very high absorption rates which are higher than with typical damping material:

View attachment 319889

The Meta generation tweeter has generally lower distortion compared to the previous generation



How much each individual of these improvements contribute to what is something you can only ask the KEF engineers who participate here.
Audibility of those is even a harder topic which in the
that’s a fair good measurement . Especially they used it to demonstrate with the same crossover. I guess in the old speakers they had a non flat top end because of this reason. To keep the distortion numbers low all across. It means if one pushes the highs on the old tweeters there is a chance it becomes distorted. On my reference 3 non meta, with the pushing of anything beyond 8K, the sound becomes unpleasantly bity.
 

thewas

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that’s a fair good measurement . Especially they used it to demonstrate with the same crossover. I guess in the old speakers they had a non flat top end because of this reason. To keep the distortion numbers low all across. It means if one pushes the highs on the old tweeters there is a chance it becomes distorted. On my reference 3 non meta, with the pushing of anything beyond 8K, the sound becomes unpleasantly bity.
I doubt that a couple of dB tuning difference (in reality its probably even less) would make an audible difference in distortion, also for example the R Meta was tuned with a bit less treble compared to the non-Meta https://www.spinorama.org/compare.h...origin1=ErinsAudioCorner&speaker1=KEF+R3+Meta
 

MarkS

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Pre-meta, KEF marketing claimed that their damping material absorbed 100% of the back wave.

Now, with meta, it's improved to ... 99%!

IMO, meta, by itself, does not make an audible difference.

Great for marketing (and increasing prices) though.
 

exm

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Pre-meta, KEF marketing claimed that their damping material absorbed 100% of the back wave.

Now, with meta, it's improved to ... 99%!

IMO, meta, by itself, does not make an audible difference.

Great for marketing (and increasing prices) though.

The Meta speakers do sound better, not by a lot but they do. Might simply be better crossovers and changes to the tweeter itself. The Meta technology? Not sure if that particular part the reason why there's an improvement.
 

juliangst

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LS60 wireless are a really nice pair speaker and they measure pretty well for their size.

But having no build in room correction or PEQ is a complete deal breaker to me.
You could of course connect a PC with Dirac or a Raspberry Pi with CamillaDSP but then the whole streaming section of the LS60 would be wasted and you'd probably be better off with a Dirac capable AVR and some R7 Metas.
 
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