Addon causes a periodic crackling sound when moving the mouse, and this ends with the mouse freezing. Rebooting PC required.

This used to be good but it adds a weird phase-y sound when im listening to music now

Works out of the box and I see it updates the youtube's Stats for nerds box with the increase in volume:

Volume / Normalized
100% / 1109% (content loudness -20.9dB)

Works nicely on some videos but does make other videos sound tin like

Warps audio making it sound like it's coming out of a tin can.

YouTube Volume Normalizer:

Current version as I write this, is working perfect.
Install, pin to Toolbar, click the new white puzzle piece icon on your Toolbar, there's some settings, I'm using the default:
1) Amplify Audio: Yes
2) Adjust to peak: No.
It just works. Thumbs up!

Finally fixed the problem of videos with different volumes being disruptive.

Doesnt work