The noise during last night lock was much better and more stationary than what we had the night before that. Closing more ASC loop helped a lot.

The first attached plot compares the time series of the band-limited RMS in the 100-200 Hz region during the two lock stretches. Now the noise is lower and there is hardly any non stationary behavior.

The most nasty feature of the spectrum is likely related to violin modes. There is a forest of peaks around 500 Hz, together with all harmonics up to many kHz.