Schiit could have done a typical subsonic filter with a sharp roll-off, but that would mean running everything through another active stage, and Schiit didn’t like that idea, so Schiit did a 6dB/octave or 12dB/octave passive filter with a shallower roll-off, but which is purely passive—as in, one or two CR pairs in the signal path, that’s it. This was the best trade-off, Schiit believed, between an active subsonic filter or no filter at all. And you can bypass the LF filter entirely on Mani 2.