If you are not using a laptop and you are using a USB 2.0 capture device, I am unhappy. Really unhappy. Astoundingly unhappy.
Changing the sync for desktop audio in the current version of OBS is annoyingly difficult due to a major internal design flaw. This is only fixed in the rewrite, but the rewrite doesn't support elgatos yet. Nor does it have deinterlacing yet.
Advanced settings:
Scene buffering time: 2000
Global audio sync offset: 1500
If you have a webcam, go in to audio settings and disable your mic, then go in to your webcam properties, set it to use the mic there, with "audio sync offset" there set to -1500. Turn on "Use buffering" to 1500.
Then go in to your capture device settings, and set the main capture device you're using to "use buffering" at 0, and set "audio sync offset" to -1500.
Last but not least, hear a scream that echos the earth, emanating from the region of the planet in which I live.