Master & Dynamic MA770 Review: This Concrete Speaker Really Rocks Ifeadi C. 07:02 WIRED, Zero Tech Blog The MA770 is a 35-pound speaker made of concrete (yes, cement and crushed rocks) that is equal parts art and audio. via Zero Tech Blog Share this Share on FacebookTweet on TwitterPlus on Google+ Related PostsThe Loony ‘Circular Runway’ Will Never Happen, But Maybe It ShouldGeorge R. R. Martin Doesn’t Need to Finish Writing the Game of Thrones BooksThis Hilarious Video’s Fake. I Can Tell From the PhysicsThe Giant Purple History of Guardians 2’s Best New CharacterThe Crazy Eruptions That Spit Up DiamondsThe Greasy Smudges on Your Phone Aren’t Grime. They’re Art