Need Help Calibrating Please

[wttmaples]

Hello. I am trying to use REW to calibrate and check the response in my studio room. How ever I can not get the signal to show up in REW. I am using 2012 MBpro Retina, Catalina - OS. PREAMP IS FOCUSRITE SAPPHIRE PRO 40. I ALSO HAVE A BEHRINGER ECM 8000. My problem is when I go to calibrate I get input signal but the output says I am at -487 dbfs and the signal is to low. What am I missing??? (I didnt know there was such thing as -487dbfs)

 

[John Mulcahy]

-487 dBFS is the dB equivalent of zero, meaning the data is all zeroes. Are you sure it is the output showing that? Can see that on the input if REW has not been given permission to access the microphone in the Mac's privacy settings. Also need to make sure you are using the V5.20 beta versions with 10.15, not the old 5.19 release.