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 PostsPhone Companies Will Soon Banish Robocalls. For Real This TimeThe Billionaire on a Mission to Save the Planet From TrumpHow TV Opening Titles Got to Be So Damn GoodDon’t Buy the Latest Trump Surveillance HypeThe Guy Behind Ello (Remember Ello?) Just Built a Better SnapchatThe Senate Prepares to Send Internet Privacy Down a Black Hole