I use Sennheiser HD560s and I found this setting no idea if I should have it on or off, if I’m missing something with it off.
It depends. For music definitely off, might be worth a try for videos and games.
I can’t get it to work anyway, but I don’t feel like it’ll do much
You can leave it on (or Dolby Atmos if you buy it) and it won’t make a difference for stereo sound. It’s only supposed to make a difference for 5.1 or 7.1 audio where it’ll simulate speakers around you. It’s great for shows or movies with surround if you only have stereo speakers. For games you may be better off using the headphones mode of the game when it has one and leaving that off.
Sonic is for mixing multichannel audio to HRTF stereo for headphones. So gaming and tv/movie watching is ideal.
All audio software with exception to equalizer APO should be turned off or ideally disabled.
On, it’s for video games and it disables itself if the game doesn’t support it.
On - but use Dolby Atmos for Headphones instead. Also works with stereo speakers.