How to connect 2 sound systems to Audio 2?

How to connect 2 sound systems to Audio 2?

So, I’ve got a gig at a place with sound system that pushes terrible bass.

I figured I can bring in my own subwoofer to set up by my booth. I have an Audio 2 and I use channel A for the sound from the place and channel B for my headphones. How would I go about hooking up my subwoofer to this?

Split channel A between the house system and your speaker? There are plenty of adapters that can suit that need.

The house system takes rca and my subwoofer pushes out a 1/4th and the Audio 2 has a 1/4 port. Having a hard time finding adapters.