Setting up stereo Rel subwoofers….

@newfzx7 i agree, that’s why I was questioning setting up a single sub then adding the second.  Do both at the same time as REL, and you, recommend.  I did end of moving my REL subs arrangement though into an asymmetrical placement that works better for my room.

Connect it to one channel only.  I don’t think there is any reason not the connect both subs following the placement suggestions from REL though and then moving subs if needed.  The original placement of the single sub might not be optimal once you add the second anyway.