Measurement:
- one geophone on the marble
 - one geophone at the sample position
 
Every stage is powered on.
| data_001.mat | nothing is turning | 
| data_002.mat | spindle is turning at 1rpm | 
Measurement:
Every stage is powered on.
| data_001.mat | nothing is turning | 
| data_002.mat | spindle is turning at 1rpm |