Most audiophiles know the more rigid the speaker case, the less resonance you get, leading to a neutral sound that replicates the audio as the artist intended. The Master & Dynamic MA770 ($3600/pr) takes this concept all the way with a case that’s built from a hand finished concrete composite. But you need more than a 35 lb case made out of concrete for great sound. You need great drivers. Each speaker features two 4″ woven Kevlar long throw woofers and a 1.5″ titanium tweeter which are tuned to provide the best sound available. Additional features include a 100 watt class d amplifier, a magnetically attached stainless steel grille, built-in 4.1 Bluetooth connectivity, and auxiliary analog and optical inputs. Overall measurements are 16 x 20 x 10 inches.