Adding a third REL subwoofer

I have had Rel’s for 20 yrs so This is my guess.. One sub is connected red to +L & yellow to +R so you get both channels into the one sub. Two are hooked up in a stereo config. with one serving left channel and the other the right. I believe there are possibly 2 ways to connect 3 Rels.

option 1 - Connect all 3 in a config like the one in which only one sub is used.

Option 2 - If you have the 2 connected as a stereo pair, then the third would be connected to both channels as if it were a single.

This way you still get both channels into the 3rd sub. I cannot see any harm to come from this and have also been considering this since I have a Storm 3 which I am not using now.

EDIT Depending on the placement of the 3rd sub, option one may be the best balanced approach. This way all three will be receiving a stereo signal.

Got it ,thank you. I just recently took a old sub and added it to the REL’s using pre out from the amp, and really enjoyed the set up. So now of course I can’t help but wonder what improvements the matching sub would bring. 

My system is in the LR so I have to find a "proper WAF" place to setup the 3rd. Those with the swarm setup are sold on it . I'll figure it out sometime soon. Right nowe got my hands full with streaming issues. Ugh