Link subwoofer to soundbar

[bachatero]

Due to unforeseen circumstances I now have a 1800 watt 18" PA subwoofer (EV ETX-18SP) sitting in my parents' living room, where I've set up the TV with a Hisense HS2100 soundbar.

This soundbar includes its own sub which appears to connect over BT, but I can't connect to it directly with my phone. So, to make this new sub work with the Hisense, I've got a few options:

1. Hack into the wireless sub's output and send that to a jack which I can then send to the EV sub. The only problem is, tapping into it looks pretty difficult unless I want to use the amplified output:
   
2. Get a BT LE module (I know it uses BT LE because the JL7106C6 MCU only supports it) and modify the name (?) so the soundbar wants to connect to it. Then, connect this module to the EV sub.
3. Can the soundbar setup and use my Kali LP-6v2 monitors which I replaced with Neumann KH150s.

What option should I consider the most here?

 

[staticV3]

I'd can the soundbar.

You can do TV->Aux/RCA to 2x XLR->18SP->XLR->LP-6, or TV->HDMI(ARC)/Toslink->DAC->RCA/XLR to XLR->18SP->XLR->LP-6,.

The 18SP has a single PEQ filter to knock down a room mode and several low-pass options to integrate with your mains.

Sadly, the lowest LPF option is 80Hz, so there'll likely be some overlap with the LP-6 which extends quite well.