Subwoofer for Kef LS50 Wireless II?

No moss grows under your system. I'm sure the differences you're experiencing between the your original SB1000 and this current SB3000 would be of interest to many.

I'm using a pair of KEF KC62s to augment LS50s with excellent result.  I was really surpirised when I experienced the more felt-than-heard pipe organ pedal notes I've previously only experienced with a pair of Velodyne HGS-15s in my primary setup.

the SB3000 thumps and gets closer to that hitting you in the chest feeling that the other two couldn't, sound quality is about the same, maybe a slight edge to the KEF......the SB3000 is still not into ultimate bass slam territory, no DB measurements from my end, I have gain at 50%, most tracks won't sound well above that, I can hear the limits of this unit past 50% gain, still fun though at 100% from time to time with a well recorded track,  my room actually sucks for sound and remains untreated for the time being,

svs recommended stock settings on the app for the KEFs with the exception of both high and low filters set to 80hz

the other two subs seemed to add bass only while this unit appears to add to the overall musical presentation, 

the gloss version I have is surprisingly living room friendly and about as nice as you can get before stepping up to some of the super premium finishes$$$ by the likes of say JL and REL

this is a poor mans set it and forget it end game music system, what KEF has done with the speaker system is special but a sub is an absolute must and the SB3000 appears to be it, of the usual contenders, I can only envision a JL Fathom trumping this unit

all of the above refers to 2 channel music