By interfaces yes, but it can also be cancelled out through destructive interference as a side effect of reflection, which is my theory of how a "big ball of crumply aluminium" is so effective compared to less chaotic solutions.
Rough surfaces increase reflection in non-specular directions and decrease it in the specular direction. I have never heard that it would facilitate destructive interference.
By interfaces yes, but it can also be cancelled out through destructive interference as a side effect of reflection, which is my theory of how a "big ball of crumply aluminium" is so effective compared to less chaotic solutions.