Kef LS50 - can it handle a subwoofer properly?


I just got a pair of KEF LS50 speakers. As is known they are active speakers and I'm considering adding a subwoofer. They have facilities for a sub but what should I do regarding bass management?, they don't have an  amp, so no such feature, and I suspect the sub will just duplicate the lower frequencies from the speakers and I would like the proper function with the highs and mids on the KEFs and the sub  handling only the lower bass. Any solution greatly appreciated. 

128x128riovinil
Only thing you need to be aware of is that they won’t play LFE tracks when you attach a subwoofer to the Kefs. They handle a subwoofer fine for music but not for movies. The signal is a 2.0 signal and there’s no proper .1 channel.
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What you need to do this the right way is two subs and a MINI DSP 2x4 total control over the bass and main speakers . 
Would as LS-50 wireless plus a HSU sub (10 inch) be good in a family room with a cathedral ceiling?
Within the limits of the LS-50 it works fine. I ran two Hsu 10 inchers but one is almost as good.