I do multiple calibrations in a row, and the calibration values for my microphones are always very close.
But everytime I do the calibration, I get the message "OK, Sensitivity Difference". But these consecutive calibration values are very close.
Why do I always get the "Sensitivity Difference" message? Is this normal?
You need to set the "Nominal Sensitivity" field in Channel Setup. The New/Actual Sensitvity is compared to the Nominal sensitivity. It is not compared to the previously calculated calibration value.
In your case (based on your screenshots), you should set the "Nominal Sensitivity" field to 45 mV/Pa. The default is 100, so no matter how many times you calibrate, if the "Nominal Sensitivity" is set to 100, you will always get the "Sensitivity Difference" message.
Once the nominal is set correctly, you can get the message "OK". The calculated sensitivity has to be within 10% of the Nominal value. You can change the percentage under the "Advanced..." button.
Here is a link to more information about using LMS Test.Lab Calibration:
Hope that helps!
Thanks PJS! If Gizma scrolls to the right on Calibration the Nominal Sensitivity can be changed there as well so you do not need to go back to Channel Setup.