These “Exposed Concrete” speakers are a grad school design project by Israeli designer Shmuel Linski. His rationale for the unusual material choice is that… well, okay, there is no rationale, he just thought it'd be cool.
And certainly more love goes into creating them than your average robot-assembled standing set:
On the project's page, he notes:
In my work I tried to give, in addition to great aesthetics, practical reasons for using concrete as a main material in a product. When concrete meets sound, it might distort the sound, because the concrete is very stiff (usually speakers are made of wood or MDF). The speakers might therefore sound strange.
He doesn't seem to resume that thought, probably because there's nowhere to go but down. Let's be frank: these speakers probably sound awful. Concrete doesn't resonate and its total opacity to sound would result in a hollow, echoing effect through the bass tube.
Still, they're cool-looking things and probably bombproof. Get a couple for your fallout shelter — audiophiles will have bigger things to worry about in nuclear winter.