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 PostsMaster Google Analytics with this $10 online courseAn ode to Chris Pratt's genius on 'Parks and Recreation'Where to mobilize if you want to see Trump crumble in 2018In the fight against measles, UNICEF has found an unexpected ally – mobile phonesBest Amazon deals for July 5: Save on Fire TV Stick, Amazon Music Unlimited, and lots of camping gearThese kids training to play soccer like Neymar in the World Cup all deserve an A+