omnimic reading both FR and distortion different today????

[lowmass]

So have been using this sytem foir last year and half with no issues. I have been developing a ribbon during this time and have made litteraly hundreds of tests and have been keeping data. Today there is about a 3 db loss in high frequency level at 20khz AND I am measuring about 50% higher distortion below 1khz than I have been measuring on this design for months. It did get very cold in the measurment room the night befor as the heat was accidentally turned off. Room got to around 25 degrees.No todays measurments were not taken t that temp. All was brought up to 73 degrees and allowed 4 hrs to normalize. The measurment mic was in the room when it got tht cold. Is it possable the mic was damaged??

[guitar maestro]

One way to check would be to verify with another driver whose FR and distortion was also measured previously. Do you have such a driver?