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KEF R Series with MAT white paper

sarumbear

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The blend between the tweeter and midrange is superb. Seems like one driver, I can't understand your count :)
Read your sentence. “Seems like one driver,” hence my mistake of thinking it as a single driver b
 

aarons915

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Responding to this post because of the attached spins but the question is really for @davidbosch or @jackocleebrown. Myself and others have noted over the years that coaxial type speakers seem to sound better with a slight downward tilt of the listening window and I'm wondering if you guys have come to the same conclusion through controlled listening tests? Said another way, would a flat on-axis response result in too bright of a sound?
 

sarumbear

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Always glad to know that my work makes other people happy!

(This is my first direct user feedback for that particular product:p)
Wow! Are you part of the KEF design team?
 

Descartes

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Any one knows when will KEFF upgrade these with meta material?

- KEF-CI5160RL-THX

- KEF-CI3160RL-THX

Looking to do transform a one car garage into a home theater doing all in walls 9.4.6

I know they launched the Ci250RRM-THX with 12th generation Uni-Q driver and meta material!
 

sweetchaos

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sarumbear

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Any one knows when will KEFF upgrade these with meta material?

- KEF-CI5160RL-THX

- KEF-CI3160RL-THX

Looking to do transform a one car garage into a home theater doing all in walls 9.4.6

I know they launched the Ci250RRM-THX with 12th generation Uni-Q driver and meta material!
It is already out as the REF series. I have 3x Ci5160REF-THX. Here was their confirmation:

 

Descartes

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It is already out as the REF series. I have 3x Ci5160REF-THX. Here was their confirmation:

That’s the reference series to rich for my blood!
Plus I only need THX Ultra2 not Dominus
 

Descartes

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…..The CiXXXXRL-THX speakers (also 5160 and 3160) have been in the market for a while now so don't have MAT, which we have been introducing into our line-up since LS50 Meta. Adding MAT does take some time as we take the opportunity to redesign the Uni-Q and crossovers (in some cases LF drivers too) and do a lot of system modifications.
Looking forward to seeing the new ones, the Reference Series is too expensive for me! Hopefully by the end of the year or sooner!
 
OP
davidbosch

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David does KEF ever let you or Jack out, I haven’t been to an audio show for years but if you were to deliver a seminar, they have more technical based lectures at the Hi-End and at the now sadly defunct Rocky Mountain shows, I would definitely attend.
Thanks again,
Keith
Hi Keith, to be honest the last three years we have been mostly just focused on product development or internal training. I did go to Munich last year but as a civilian. There's a couple of very good seminars online by Jack on YouTube (compression drivers and speaker design). I have two or three mini-seminars online, albeit in Spanish... in case you want to practice yours!
 

exm

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@davidbosch Maybe you can help solve another mystery: why is the Reference 2 Meta (same as with the non-Meta by the way) rated as 80Hz – 35kHz (±3dB) whereas the R2 Meta and R6 Meta (65 Hz - 28 kHz - same size drivers) are rated lower? The R6 Meta and Reference 2 Meta should have similar stats, with the Reference going slightly lower, no?

On a side note, the US site has the Reference 2 Meta listed as 'Three-way bass reflex' (instead of closed box).
 
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davidbosch

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I guess this is turning into an AMA, so I gotta ask: what's your view on cardioid (midrange) speakers? Why are we not seeing more of them? It seems to me like you had a good opportunity for that with the Blade and LS60 :)

I guess the benefit isn't really evidence based, particularly below Schroeder, but the reception for DD 8C and Kii Three have been great, for what it's worth.
Hi @jaakkopetteri I thought this was an Ask Me Anything (about the white paper). Just kidding! My (very general) view on them is that some of the methods for achieving a narrower directivity at lower frequencies (DSP and/or acoustic), at least in this kind of speakers, not big arrays for concerts or that kind of thing, seem to have some limitations that put a question mark on whether they actually help make the stereo image more realistic and holographic in a good room. Blade is passive, so I doubt it would be the right platform to test that sort of thing. LS60W is active, but both Blade and LS60W already do a very good job at stereo imaging, thanks to the tight packaging of the drivers and the low diffraction cabinets. There's also still lots of questions to answer about what a preferred power response is, but smoothness seems to be where the money is at, and that's really what we have been after with our systems. Your point about narrowing directivity at low frequencies is a good one, and I agree, we need to understand this better.
 
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davidbosch

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With all these lossy damping materials, especially the neck decoupler - how stable are they? Would they ever change properties over a reasonable time frame and affect the response?
Hi @Penelinfi, very valid question. These components made of different rubbers will have a similar lifespan to other rubbers in the system and maybe much more than the surrounds, which can be subject to high stresses. We have been doing cone neck decouplers since Q series (from 2011?) with no issues related to ageing. In the case of the decoupler, ambient temperature can make it softer or harder, like any rubber, this has an effect on the resonating system cut-off frequency (i.e. the decoupling mechanism), but you have to be at very uncomfortably cold or hot temperatures for this to affect the driver response, and still this happens in the frequency region where the MF is low-pass filtered, so the worst case scenario is a bit of the MF output 'peeks through' the tweeter response more than it should.
 
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davidbosch

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Too bad the LS60 doesn’t have the same shape as the blade in smaller format!
Hi @Descartes, I fully accept maybe I'm biased on this but to me LS60W has the shape it has to have. It really is very slim for the excursion of the LF drivers. The Uni-Q is already almost its width, so diffraction really isn't a big issue, thus why it didn't need a curved baffle. Being so slim, the LF section needs to squeeze as much internal enclosure volume as possible, so the squared profile helped maximise the internal volume for the chosen footprint and height. And finally, Blade is a bit of an industrial design statement, LS60W is a much more affordable product for more people, so in this respect I think it's ok we didn't try to dress it in a sculpted cabinet driving its price up. Maybe this is the wrong analogy but in the car world car designers like Giugiaro made the most of boxy and angled body panels in the 70s and 80s trying to help brands like VW and Fiat make good design affordable for more people.
 
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davidbosch

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So to summarize: you're saying that a Meta R-series Uni-Q driver will sound better than a non-Meta Reference Uni-Q driver? I'm mostly wondering about my Reference 4 center - will the R6 Meta be superior?
Not exactly, I said it performs better. But we can only listen to it in the system, not the Uni-Q in isolation, and the systems have enough differences that I think the 2014 Reference is still superior. I'll give you this though: one area I would say we made the R Meta models clearly better than Reference 2014 is the tweeter. It just is better all around, it really does sound cleaner and sweeter. Also, the approach to a smoother power response through crossover design is an obvious difference and this has an effect on the speaker's ability to convey a stereo image. Although I have to say it was done very well in 2014 Reference. About your centre channels, remember Ref 4 has a ported LF section with four 6.5" drivers, whereas R6 Meta has an LF section with two 6.5" drivers, both LF response and distortion will be naturally better in Ref 4. However, I think the balance in the R Meta centre channels was done better, we just have better tools for crossover design than we did 9 years ago.
 
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davidbosch

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I really appreciate the input from Kef, here on ASR. Thank you for this. I hope your contributions will continue and that you will find this a useful medium for communication with your customers.


As this seems to be the best place to ask Kef related questions at the moment...

I wonder if anyone can offer advice on the range of recommended room volumes that are appropriate for each model in the R series? (I looked briefly but didn't find it on the datasheet).

...Or perhaps Kef don't think there is such a relation - in which case I'd be glad to hear their reasoning.
I will be very honest with you, I could give you room sizes, but they will probably mean nothing once you account for all the variables such as proportions, building materials, treatment, speaker positions, listener positions, etc. As well as your listening habits (type of music and how loud you want to play it). As you know the larger the room, and the farther away the listener is to the speakers, the louder they will need to be played to sound as loud. The R3 Meta is surprisingly very capable of producing ample clean bass but it does have a ceiling that becomes obvious in large/lossy rooms at high volumes. R11 Meta goes extremely loud before it distorts but in a small room where the stereo triangle will be less than 3 metres per side, the LF array is relatively too big wrt the listener so the stereo image will suffer. If you're in the UK, a lot of people find R5 the right compromise between size, footprint, bass extension and distortion capabilities (and price) for the size and construction of living rooms we have.
 
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