Subwoofer for Kef LS50 Wireless II?

This new Kef sub is getting some great reviews!
https://www.soundandvision.com/content/kef-kc62-subwoofer

What kind of problems are. you having? Is the sub boomy or muddy?

Boomy would probably be do to the subs location in relation to the listening position, muddy would probably be do to improper crossover setup. 

I'm assuming you only have one sub.  Have you placed it in your room in the most optimal location? (google sub location crawl method)

Set the crossover on the sub at 45 Hz and the gain to 75% as a starting point. Plug the port on the KEF's

There is a document on the KEF website pertaining to integrating the LS50 to a sub.

https://us.kef.com/pub/media/wysiwyg/ls50/LS50WII-Subwoofer-Setup.pdf

I certainly would NOT worry about the high level inputs. I've always found the low level inputs to be preferable. Simply more detail. The SVS, while not the best, should be very good with your speakers.

Non sense...On the Rels use high level....Although i havent heard the Tx series ive had some first hand reports,  I wouldnt waste time ...go for their best selling sub in their lineup if you can swing it.. the S510...will step all over this Tx series...im running a stereo pair coming off the Ti series...fantastic

OK, missioncoonery. You must be an expert. Just gave my opinion from MY experience.