“As bass music aficionados turn their attention away from obsessively classifying dubstep, Joker’s brand of mid-level “purple” starts to resemble nothing so much as dialed-down trap music. But the Bristol producer has been making his own version of post-dubstep heaters for years now. After the pop-leaning flop that was 2011’s The Vision, “Newham Generals” finds him back in his zone, teasing melodie”