Hold on, just to use this app you need REW first? 20 bucks doesn't get you all the way there? That kinda stinks and REW is way over my head so forget that. [emoji1787]\n\nSent from my Pixel 4 XL using Tapatalk\n\nno. You do not need REW (free) and a Umik (~$100) to use the app. The app id Audyssey-centric. Instead of using the reveiver as the brain, the app uses your device as the brain, and directs the initial measurements through your phone or tablet. You then Send the calibration to the AVR when you are done. Other than that, it operates just as Audyssey would otherwise operate.