Carnage and Whispers of the Endless Paths

I'm considering doing a Barbarian greatsword build and I was wondering how carnage works with Whispers of the Endless Paths. Does it apply carnage for both hits or just does it use the relatively low base damage once? What about for abilities like Barbaric Blow or HoF?

Barbaric Blow (and seemingly all other active attack abilities) trigger for all attacks in the aoe.