To be honest, I haven't been impressed with the R11 LF performance. I have tried a bunch of Kef speakers: the R11 was my first replacement of the 1990s Reference Fours. Well, that wasn't a fair comparison (talking LF only). Next, I tried the R900s which really blew the R11 away in my opinion. The R11 might be more controlled (so they say), but it's lacking the "oomph" factor (I know, I know, that's what subwoofer are for. But still. Anything above 80Hz matters). That's to me where the Reference 5 shines: it has the same number (4) and diameter (6.5") of LF drivers but that's where the comparisons stop. The Reference drivers are completely different, with totally different internal LF enclosures.
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