I have a weird issue going on with my UMM-6 calibrated mic. I am generating pink noise and using REW SPL meter and a CM-140 SPL meter placed next to each other and the UMM-6 is reading 10db lower than the CM-140. The only reason I did this was because I could tell tell UMM-6 was not giving an accurate reading. I'm not worried about absolute SPL levels just want to be in the ballpark so I know what SPL i'm measuring at. I'm using the 90deg cal file with sensitivity. Do you think this is just something I should ignore or delete the sesitiviy factor and just calibrate myself. Could it possibly be a faulty mic or bad calibration? I can hear a difference of 10db and I'm sure my CM-140 is closer to the proper reading.