The Cona is a slightly odd 'sub-woofer' as it has a high top frequency which means it can be hear directionally - so unlike most, placement is important. Not sure it adds a huge amount - I would probably suggest you could get a better result by just upgrading the other speakers. I like CX100s but there are many better passive B&O speakers. The Cona was designed to work with the C/CX range though and will increase the bass a bit.It should not be compared with the Beolab 2 though as it simply will not produce the same level of bass.