Once upon a very long time ago, my Windows audio was *lacking* bass. Linux was fine, on the same hardware, so the hardware was fine.
Turned out to be a Windows driver problem. I have no idea why a driver would do that, except on purpose, but updating Windows' driver fixed it.
Another thing to check is whether you have any filters. OBS doesn't add filters by default, but someone else might have? Likewise for any other processing outside of OBS, like Windoze's "audio enhancement" that is managed as part of the driver. (Windoze tries to be "smart", to "help the average idiot", but often ends up being stoopid instead)
