I don't know why Firefox's volume is always capped between 10% and 20% no matter how high you set the volume on some videos but this lets you fix it.

My only complaint is that the equalizer can't be set to a specific volume and made universal for all future tabs but, again, that is Mozilla's bad code not the developer.

This kind of auto-equalizer should be built into Firefox by default but I guess it's too much to ask that Firefox's sound code work at least as well as Internet Explorer in 1990....