You would think this sort of functionality would be implemented in sound cards but I can't think of any significant advancement in audio processing in years.
It would be really good to have on a TV too (no more super-loud explosions interspersed with barely audible speech), and I'm amazed that YouTube seemingly doesn't normalise sound levels at all.
As a relatively new Win10 user I find access to mic levels being buried in device manager to be crazy. Also, not having a default output mix, apparently ...
At least games seem to offer a good range of sound settings.
Right click on the speaker icon on the bottom right notification area, then click "Open Sound settings"
If you want the legacy sound control panel that you may have been used to from pre-Win10, then from this dialog click "Sound Control Panel" on the right. (Or Win+R "mmsys.cpl")