Following the Yokozawa-san's original post, I just checked the spectra by my self and compared some, and found strange points.
In Fig. 1,
PRFPMI Unlocked (only IMC locked with IMC ASC)
Fig. 2 is the one that the red curve is removed from Fig. 1 for clearity.
What I found are:
I showed the spectrogram.
There are so many glitches above 100 Hz.
I may select accidentally not good timing for before IFI work(9:00) and accidentally good timing for after IFI work(12:00), but its spectrum is strongly depend on the glitch.
So, the effect of sound protect sheet is still unknown.
Anyway, please don't believe the spectrum of klog24526
The 128Hz bump, which is suspected to be an environmental noise, is not changed.
I removed all rubber sheets around 12:00 on 28th March.