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Really, really enjoyed this! I’m absolutely sure there will be a KEF Meta product in my house in the future after reading this.
There was a lot of discussion a while back about what's the reason for R5 when the performance seems to be about the same as the R3, discounting the look aspect. What is KEF's reasoning here?
You guys rock. I am extremely happy with my in-walls. They replaced also top of the range JBL in-walls and the difference is, if I can use a cliché, night & day!
@davidbosch Did you miss this question? I'm not sure I've seen dispersion width mentioned in the Kef papers and am interested in how you decide what is ideal.
In his book (3rd edition, 10.5.1), Floyd Toole wrote that in order to have a predictable experience the listener-speaker distance should be 3 to 10 times the largest dimensions of the sound source (as by Berabek,1986).
Which JBL did you have?You guys rock. I am extremely happy with my in-walls. They replaced also top of the range JBL in-walls and the difference is, if I can use a cliché, night & day!
Hi @aarons915 sorry I almost missed your question. In the case of the Uni-Q and for the system configurations we have, this seems to be true. I really am not sure if this can be generalised to the whole world of coaxials, as there are other designs out there that don't have a phase plug on the tweeter and don't have a waveguide design (and crossover) to match the tweeter and midrange directivities around the crossover frequency, so how they're actually illuminating the room off-axis can be quite different. I'd have to listen to more of them and see their measurements to be able to tell you.
I think there might be a mistake here actually. Sorry, this is embarrassing. I'm checking with the colleague who published this data and will clarify the mystery shortly.
Hi, in short, the LS60W. Just take a look at it, the LF driver array is much more compact and closer to the Uni-Q, so vertical directivity in the LF to MF crossover region in particular is wider, you can see this from the directivity contours in the LS60W white paper. Higher up in frequency, the midrange cone is smaller so it becomes directional higher in frequency. The baffle is also smaller, and in particular slimmer, so the tweeter doesn't need a shadow flare (waveguide continuation) to minimise diffraction, widening the directivity marginally. The tweeter is also smaller but with the phase plug it doesn't really matter too much as, together with the horn, it controls the tweeter's directivity and makes it more constant in both cases. I would only add that despite this, the R Series driver array and cabinet provide a particularly smooth directivity. The Uni-Q and the symmetrical array of LF drivers around it, as well as the slim cabinets are already an excellent package.
Hi @Descartes , I have no idea! unfortunately. I am not involved in what events we attend, particularly outside of the UK. KEF is in the sponsor list but oddly not on the list of speakers to listen to.Will KEF participate in this event? This would be nice to see how the new R series with meta material technology does vs Revel and a few others!
The 2023 TSR Speaker Shootout | Colorado | The Screening Room AV
Have you always wondered what makes a good speaker sound good? How manufacturers design their speakers? How visual bias can change your perception of sound? Have you heard John Schuermann harp endlessly about how important off-axis response is and want to find out of he's right? Then, come to...
Hi @bodhi , I get what you mean, from the published standard specifications, it kinda seems the R3 and R5 perform too similarly. But the R5 has more LF volume displacement and more LF enclosure volume. This does result in more bass extension and less distortion and more power handling (2 voice coils for the LF will fry slower). The symmetric array of LF drivers also gives a symmetric vertical directivity along the LF to MF crossover. All of this makes R5 superior as a floorstander. R3 though, can be put on a stand, table, shelf, etc. which a lot of people actually need.There was a lot of discussion a while back about what's the reason for R5 when the performance seems to be about the same as the R3, discounting the look aspect. What is KEF's reasoning here?
Satisfied R5 owner here and I'm have not yet decided on which meta I will upgrade to, R3, R5 or R7.
Hi @tifune, I think I rather not, as I'm not posting as a civilian here, so apologies. Controlled directivity into low frequency sounds ideal, but in a room below the Schroeder frequency I'm not sure it's yet well understood how such speaker will interact with the room modes.
These ls60 plus a possible KC92 will be the end games for most people hmm.
I completely missed this question! sorry. If you're talking about the Uni-Qs: the Uni-Q tweeter and waveguide geometry are essentially the same for all Uni-Qs with a 1" tweeter since the Muon launched in 2007. R Series 2012, 2018 and Meta, as well as Reference 2014 and Meta all share the same tweeter profile and waveguide geometry. We might have done small modifications to it but it's basically the same. Why? Our Head of Group Research, Mark Dodd, who oversees KEF and Celestion, was thinking before that time about how to improve the propagation of spherical waves from a tweeter with a non-flat pistonic diaphragm and in particular a hemispherical one. He concluded that an infinite conical waveguide with a spherical cap tweeter diaphragm with coincident centres (and a particular angle) provided a superbly smooth directivity and bandwidth and that this held if the conical waveguide was truncated and smoothly flared out into the baffle. That's the basis for the tweeter dome and waveguide geometry we use since.
