I have never found a need to do that because after running setup the unit always levelled matched to within 0.5 dB. You can check it just to see, it doesn't take long to do. Be sure to place your Umik-1 mic in the same position where you placed the Audyssey mic during setup.\n\nGot it! \n\nI always thought REW was a tool to attempt to enhance the sound but it seems like it's more used for confirmation. Am I off on that?