I couldn’t find a manual yet, but having a look a the back of the unit and reading the site, it should work like this:
RCA from your controller to the first Lightwave RCA line 2 input. Then the line output from that Lightwave with an XLR cable to the other L Lightwave Mic/Line 1 input. Also set the mic/line 1 input on the second Lightwave to the 12 o’clock position. You should now have sound from both speakers.
Otherwise you may have to split your RCA cable and run one connector to your Left and the other to your Right speaker.
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