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KEF Q Meta is Coming

billou5767 said:
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Well, the 2018 R with wadding damping.
1728224647620.png
1728224686816.png
From the white paper. Also: "the dome vents through the centre pole of the magnet system to a cavity filled with absorbent wadding. The cavity is tapered to that, when the wadding is inserted, it becomes more dense towards the rear of the cavity, gradually increasing absorption.All the rearward energy is absorbed and cannot re-radiate through the dome after being reflected at the back of the cavity." So that would be (about as) good ass well. Edit: I guess the MAT is more 'complete damping'/efficient, so, if it takes the same cabinet room for example, it has more room inside, so less pressure differences.
 
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Rõlnnbacke said:
Well, the 2018 R with wadding damping.View attachment 396894View attachment 396895 From the white paper. Also: "the dome vents through the centre pole of the magnet system to a cavity filled with absorbent wadding. The cavity is tapered to that, when the wadding is inserted, it becomes more dense towards the rear of the cavity, gradually increasing absorption.All the rearward energy is absorbed and cannot re-radiate through the dome after being reflected at the back of the cavity." So that would be (about as) good ass well.
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good remark : the mat seem in the center : more for the tweeter

on the concerto the bass speeker we strangely dont see it :
1728226037248.png
 
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billou5767 said:
good remark : the mat seem in the center : more for the tweeter

on the concerto the bass speeker we strangely dont see it :
View attachment 396899
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You can't cancel the bass waves if you want output from the ports, it would be interesting how it works on bass drivers if at all, if it did I would think you wouldn't even need a cabinet, just a baffle
 
Digital_Thor said:
Would the Meta magic even work that well for a midrange? Has anyone tried?
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Theoretically, metamaterials can be designed to damp any set of frequencies, as this style of layers started to be use for noise reduction in factories.

I think the one KEF uses is optimized for high frequencies.
 
Vacceo said:
Theoretically, metamaterials can be designed to damp any set of frequencies, as this style of layers started to be use for noise reduction in factories.

I think the one KEF uses is optimized for high frequencies.
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So.. actually fitting something big enough to matter at those midrange frequencies.... too large?
I'm only considering above 400hz as the R version needs. And would it even be plausible to build yourself - worth it for that matter?
 
Digital_Thor said:
So.. actually fitting something big enough to matter at those midrange frequencies.... too large?
I'm only considering above 400hz as the R version needs. And would it even be plausible to build yourself - worth it for that matter?
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That would be a question for AOR or Dr. Oclee-Brown, who, after all, designed and adjusted the speakers; MAT included. ;)

billou5767 said:
they wait 11 gen to see tweeter no good :p
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Have you seen the Nautilus with their long rear spikes? MAT is meant to provide the same functionality.
 
Digital_Thor said:
So.. actually fitting something big enough to matter at those midrange frequencies.... too large?
I'm only considering above 400hz as the R version needs. And would it even be plausible to build yourself - worth it for that matter?
Click to expand...
The MAT for the tweeter appears to be an array of folded tubes (for want of a better description) of various length, the length tuning each tube to a specific frequency. The array together covers the working frequency range.

Different metamaterial structures have appeared in papers, such as small square cavities each tuned with a different port size (a square hole) to tune the frequency. These have been proposed and measured as potential bass absorbers, so midrange should be possible. Whether it would be effective in a speaker cabinet would need some research, possibly already happening in a company or university.

The papers had good descriptions of the structures, and most seem to be viable for DIY. 3D printing, laser cutting or a CNC router would all make it a lot easier.
 
Erin’s review is online:


IMG_1789.jpeg



IMG_1790.jpeg
 
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Vacceo said:
That would be a question for AOR or Dr. Oclee-Brown, who, after all, designed and adjusted the speakers; MAT included. ;)


Have you seen the Nautilus with their long rear spikes? MAT is meant to provide the same functionality.
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the high its what you lose 1st when you become old

old man have money and dont need hight :p
 
Digital_Thor said:
So.. actually fitting something big enough to matter at those midrange frequencies.... too large?
I'm only considering above 400hz as the R version needs. And would it even be plausible to build yourself - worth it for that matter?
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Plausible to build yourself? Sure. It would have to be larger - either 2x or 4x the one in use in the R meta and Ref meta. (I can never remember the frequency/size relationship). The parts are nothing particularly special, being injection moulded. A hobbyist could certainly 3D print a functional MAT disc. In fact, we've printed functional MATs ourselves on some fairly common 3D printing hardware. The challenge is the design - we spent a long time working out how to best match up the disc with a normal tube that comes off the back of the tweeter. The result of that investigation is the subject of the patent we have in this area. The answer is a conical duct that tapers at a particular rate, with a relationship to the lowest frequency of MAT. This is fine in theory, but actually designing something that works for your situation gets tricky and pretty much necessitates the use of FEA. Not to underestimate the dedication of ASR users, but I would imagine that few people have access to those kinds of resources.
 
AOR said:
Plausible to build yourself? Sure. It would have to be larger - either 2x or 4x the one in use in the R meta and Ref meta. (I can never remember the frequency/size relationship). The parts are nothing particularly special, being injection moulded. A hobbyist could certainly 3D print a functional MAT disc. In fact, we've printed functional MATs ourselves on some fairly common 3D printing hardware. The challenge is the design - we spent a long time working out how to best match up the disc with a normal tube that comes off the back of the tweeter. The result of that investigation is the subject of the patent we have in this area. The answer is a conical duct that tapers at a particular rate, with a relationship to the lowest frequency of MAT. This is fine in theory, but actually designing something that works for your situation gets tricky and pretty much necessitates the use of FEA. Not to underestimate the dedication of ASR users, but I would imagine that few people have access to those kinds of resources.
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Hypothetically, would it be possible to fill all the internal walls of a cabinet with metamaterials meant to make them innert in pretty much all frequencies. The practicallity of doing that is nowhere to be found, I´d imagine.
 
Vacceo said:
Hypothetically, would it be possible to fill all the internal walls of a cabinet with metamaterials meant to make them innert in pretty much all frequencies. The practicallity of doing that is nowhere to be found, I´d imagine.
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no

wave like water , the mat its back of speaker , and go in a direction in labyrinth : iks like a bottle on something : water imitate the path

if you do in a case , its like water in a bag , if you turn the bag its chaos
 
I hope he gets a floorstander for measurements
 
I speculate that the kind of uni-Q drivers of the Q1 and Q3 probably didn't receive huge changes.
But the 4" Uni-Q of the Concerto and towers seems to be a new design and might perform better.
 
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