I just finished using REW with calibrated microphone (umik-1) to perform room corrections for my 2.1 system. I was able to figure out relative subwoofer volume, best cross over point and generated 4 PEQ correction to flatten the response. Doing this with the app was super easy - I only wish there were more PEQ points. Can I hear the difference after the correction? No. Was it fun? Absolutely