I decided to find out for myself what the results were and found that the above method doesn't give the same modal frequencies.nThe Free-Free mode 7 was 121.8 Hz where the disks were twisting in opposite directions.nThe Kinematic Mount mode 1 was 85.8 Hz where the grounded disk didn't move, and the other disk twisted.nNot the same at all. I look forward to other members suggestions.n