This is an issue that I had with OBS and I found a simple fix to fix this. At least I think so. The problem is basically that my audio was 'soft-clipping'. It wouldn't go completely top to bottom but the audio was actually distorted. Whether I used filters or not, or added a Limiter or Compression it made no difference. The problem is that this is an issue with Pan's Law (at least I think it is) and the fix to fix this is simply to add Gain in your Filter and add 3 DB of gain. Once you do this your audio will now properly show that you are distorting your audio and your rendered videos will also show the proper distortion - which allows you to fix your knob properly - whereas it wasn't possible to really tell before.