LISTEN TO NOTEBOOK HEADSET DOUBLE?

Person A talks to Person B.

Person A uses a jack headset on the notebook, person B uses a headset on the PC.

Person A hears and understands everything well.

Person B hears person A well, but also hears himself.

I think person B also talks about the mic on their notebook? But then I would also hear them twice or not?

I tried a lot in Regedit, HeadsetCapturVolume, HandFreeVolume, HandSetVolume etc… Can someone explain exactly what they mean and where I have to start?

Maybe you've turned that on, you use it to listen to everything

Where, then? In the system settings? In the regedit?