Question / Help Sound Issue (video proof)

[Berdy]

Hi guys,
i have an audio issue with OBS: the sound isn't "constant".
This is what i'm talking about:
https://www.youtube.com/watch?v=dz0NVtPgQII
https://www.youtube.com/watch?v=dz0NVtPgQII
I don't have this problem with Avermedia RECentral, so I think it's a problem with OBS