Figure 1, the observed B1 spectrum and the projected scattered noise. The coupling factor is 3 times larger than for SDB2. So SDB1 is a more critical bench in terms of scattering.
Figure 2, the same for the quite time the noise is about a factor 10 below the sensitivity curve in the 20-80Hz range. So not that far away.
It would be good to look through the viewports with a IR viewer and at the IP cameras to see if there is some obvious source of scattering on SDB1.
