Fast linear provides the flattest response. Although you can’t really tell the differences, they’re not really EQ. But if you do then the best is always what sounds the best to your ears.
The filters are not meant to filter the audible audio curve. Some persons may get fatigue or other symptoms listening (long) to PCM output above all using headsets. DSD has no problems in this area and only simple low pass filters are included. For this reason these PCM filters were developed. Experiment with them if you experience any kind of hearing problems when listening to music.
