Welcome to the Forum, Ralphie!
Sorry, but I can’t tell from your post what you’re trying to accomplish.
Is this all in Cubase? I’m sorry, but you’re not going to find many people here who are familiar with it.So i made some measurements from my L & R channel
did choose generic EQ
applied filters from 0 - 5000hz.
all looked good and made sense so far
chosen export to filtered impulse
choose stereo 16bits
L measurement on top selection box
R measurement on bottom slection box
If you’re talking true stereo, REW can’t do that. It only generates monophonic signals. If you’re satisfied to have that in two channels, you could just use a splitter.I just need a stereo impulse of my room (which should be easy to create with REW right?)