what free font is similar to this

Encorpada  Suggested by LuluStar 
Harriet Display Bold Italic  Suggested by gibsonburst 

This ligature is superb, it must be a custom one.
But the base font is probably (if not, similar to) Encorpada Pro.

Harriet is also very close. Vox uses Harriet for its subheads, and I'm betting Harriet was the base for the logo but that it was altered by adding a ligature and filling in the serifs on the x.