Hello - I need to setup a sub outdoors….  No options from Sonos…   My issue question is connecting the Sonos Sub Out (RCA) to the Sub’s amp.  When looking for an amp, they ALL seem to have an input for Left and Right RCA.  How do I connect the single Sonos Amp RCA output to Left and Right RCA inputs?  Splitter?  Connect to one of the two inputs? 

  Thanks!