I downloaded new accelerometer huddle test data from last night and analyzed it. This new data set is ~55 mins and uses the same Wiener filter parameters as previous huddle test analysis, the main difference being six accelerometers used in the Wiener filter and the improved experimental set up.
After computing the ASD for the self noise for each of the six accelerometers, (being witnessed by the remaining five), we get,
Now computing the mean of the above signals and the corresponding error bars gives the following result,
Comparing to prevoius huddle tests, I can note two trends on the Wiener subtraction:
1) When using six accelerometers, the subtraction above ~8 Hz drastically improves.
2) When using three accelerometers, there is better cancellation in the 1-5 Hz region, see http://nodus.ligo.caltech.edu:8080/40m/11442. This might have to do with how much more closer the accelerometers are to each other?