Is there a good way to remove DC either in the ADI-2 DAC FS or using Foobar2000?
I assume this is DC, during silence the view on the dac or in digicheck:
... Or is this just some low frequency stuff that I fail to hear?
This is from (some of the first tracks of) the Album J.S.Bach - Matthaus-Passion (conductor. Hermann Max),.
I can clearly hear typical subsonic room noise with my AUDEZE LCD2r2.
Happens quite often with church recordings when certain types of microphones are used, i.e. Bruel&Kjaer 4003.
The source can be outside wind or heating/air condition noise, sometimes even distant traffic (not in this case).
Nothing to worry about:
if you don‘t hear noise you don‘t have a noise problem.
DC removal is best done on a per track base, with a specialized function in software.
This function analysis the DC content of a whole track and subtracts the DC.
Working, but less ideal is low cut filtering, typically below 2 to 5 Hz.
This affects the audio range and peak level due to phase shift and does not remove the DC in the very first beginning of a track.
Therefore it needs to be done by the producer BEFORE cutting away the empty part in front of a track for the release version.