I am wondering the same thing for the same reason.
Before I started using Videobox i just had MPC (Media Player Classic) loaded up with a random playlist and it had the option to normalize all audio. And it did it well. Loud stuff was not messed with and quiet stuff (Pink Floyd) would have the volume increased till it roughly matched the loud stuff giving the over all effect of everything being the same "loudness" with out messing up the dynamic range like the built in windows 10 normalizing does. The way the Win 10 does it is it squashes loud stuff and quiet stuff is still quiet and it ruins the dynamic range in most everything that passes through it.
Does Videobox use its own internal player or is it using an external one and if external what is it using?
Thanks.