Can this not plug into 2 studio monitors?

http://www.roland.com/products/en/UA-4FX/

For the avg RCA set of monitors, does each 1 require a L & R signal or does each 1 only require 1 signal

Someone told me for each monitor you need a red & white, & now I'm hearing you only need 1 depending what side the monitor is on..

This might be a dumb question, but I just want to make sure I don't need to buy a new interface b4 I get new speakers


1 last thing... if the 3 coord midi plug gives better quality to speakers, is there anyway to have a 3 coord midi on 1 end an a 5 coord midi on the other?