I tried a new DHARD Y filter that should reduce the noise injected from DHARD Y between 10-30 Hz. It's about 6 dB improvement. I ran 10 minutes quiet DARM after the test starting Mar 13 4:36 UTC (Mar12 21:36 local). No apparent change in the low frequency noise in DARM.

The filter engagement works, so I added it to the "LOWNOISE ASC" state of the guardian. It's in FM8 and engages with other DHARD Y boosts.

Gabriele ran a bruco for me, looks like this was an improvement-

before dhard y change bruco

after dhard y change bruco