Need to connect prewired Home speakers to X1

I have 2 sets of speakers prewired in the house that we just moved into, where the wires are coming out of the wall next to the TV. I already have a soundbar connected to the TV via HDMI. I would like to add the two speakers to enhance the sound since they are already there. I do have have any compatible output jacks on the TV or soundbar to connect to the speakers. Can I use the Audio output RCA jacks on the X1 box to plug in the red/white jacks and splice them  directly to the speaker wires? If so, is there any conflict between the output on the HDMI and the output from the RCA jacks?