KEF Meta Absorber

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vinylnvalves
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#1 KEF Meta Absorber

Post by vinylnvalves »

I saw this https://www.theabsolutesound.com/articl ... echnology/

Interesting it’s hailed as innovation, yes they patented it on application, but washing machines and cars have had cactus style Helmholtz absorbers for a long time. I was thinking could this be scaled up to cover the midrange. I think it would either be massive or ineffective. Bit like having a small square of a perfect absorber in a speaker cabinet. Yes great for tweeters only in IMHO. Shame as one of the easiest things I could make on the CNC router,
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Nick
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#2 Re: KEF Meta Absorber

Post by Nick »

I would have thought that the rear wave of a tweeter would have been easy to absorb and convert into heat with wadding.
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Scottmoose
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#3 Re: KEF Meta Absorber

Post by Scottmoose »

It is. Although it can take some careful juggling of the type used, its quantities and location for best results, and if combined with rear decompression chamber[s], it gets a little more complex as there are usually some other effects coming into play (typically in the 2KHz region). Nothing particularly out of sight though and with a few days of testing it should get dialed in. In fairness to KEF, this seems a reasonable alternative though, and may improve production consistency -positioning damping material can be a pain; I've known cases where a misaligned felt pad on the rear of the coil caused roughly a 3dB deviation in the response of that unit, so if you can avoid that by substituting a pre-cast item, potentially no bad thing.
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vinylnvalves
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#4 Re: KEF Meta Absorber

Post by vinylnvalves »

It might be a better way of absorbing the rear wave in a compression driver. Which is similar to what kef are going. I was always concerned that the thin layer of foam in my JBL’s wouldn’t do anything below 500Hz.
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#5 Re: KEF Meta Absorber

Post by Scottmoose »

I'm not sure it would be ideal for those drivers. You don't exactly want to be depressurising a compression unit, and this is likely to be a better solution to slightly larger chambers where eigenmodes can be an issue. Not impossible of course, but I suspect alternative solutions are likely to be more effective, if standing waves are proving to be problematic. The impedance curve is probably the fastest way of establishing that.
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