Connect sub to active speakers - how?

[AlmaataKZ]

How do I connect a sub in this setup: stereo pre amp (with balanced TRS output) to active speakers (with balanced xlr input)? Sub has low level rca input and hi level neutric speakon input (which I beleive can be connected simultaneously).

I also need the sub to work for multichannel. The stereo channels of multichannel are connected like this: avreceiver pre out to the above stereo pre in (at a pre-set vol setting).

 

[AlmaataKZ]

Anybody can help?

 

[AlmaataKZ]

Guys, can anyone look at this? I asked a guy in a hifi shop, he did not know. I asked a guy from Rel, in reply he sent me a picture of an xlr splitter and a paragraph about the benefits of simulteneous hi and lo level sub connection. Still cannot figure out if it is possible and how.

So, the problem: I am thinking of getting a set of active ATCs (assuming they have only xlr in). I also plan to have a dac/pre amp with balanced out. One candidate has xlr, another one has TRS output connector.

I want to know if it is possible to use a sub in this set-up.

If I use an XLR-to-2XLR splitter on each L and R out of the dac/pre (which is what the Rel guy was possibly suggesting), one set of L and R goes to speaker (OK...), but then how do I feed the second set of L and R xlr to the sub? first, I need to mix both channels and then I need to connect to the low level in of the sub. How do I do that? Or is there a completely different way?

People say that with ATC actives you don ot need a sub. OK, this remains to be seen, but is sub connection possible with a preamp and active ATCs?