I had noticed on the Detchar pages that ITMY had been doing a lot better between 1 and 10 hz than the other BSCs, so I started poking around in filters to see what was wrong. The FF filters were all the same and isolation loops all looked roughly similar. On Hugo's suggestion I looked at the L4C blend in on HEPI and the FF in on the ISI. The signals should have been exactly the same, but the ISI showed less signal at 1hz by a factor of  ~2 (first image, HEPI is red, ISI FF is blue). The only filters applied on both platforms a that point are a calibration filter and a symmetrization filter. On HEPI (second image), the calibration is just a gain (red trace), the symmetrization is a notch filter that smooths the L4C response(blue). On the ISI (third image), the calibration filter is a notch filter (red again), and the symmetrization filter is mostly flat filter that tunes the calibration filter slightly (blue trace). Either approach is fine, as the product of the cal and sym filters stays the same, (green taces on both pictures). Unfortunately, the ISI HEPI FF L4C cal and sym filters were not loaded in a consistent manner on most chambers (ITMY was done correctly, so FF worked there!). Basically the other chambers were using the blue trace on the first plot with the red filter on the second plot. This effectively cut the FF L4C signal in the region we needed it most. I've now loaded right, consistent set of filters from HEPI on the ISI FF path, so we should see a good improvement on most of the chambers in the 1-10hz region. One dof for ETMX is shown in my fourth image, blue before, red is after, I'll try to get a more complete comparison tomorrow morning. I haven't finished the doing gain matching on these chambers yet for the FF path, whcih should improve this a little more.