Since 2012, London DJ/producer Daniel Avery has been developing an unusually elegant take on techno. He can bang with the best of them: The title track of his 2013 album, Drone Logic, builds a crushing climax out of squealing filters, and 2016’s “A Mechanical Sky” is an extended display of acidic intensity. But even his most cavernous anthems, like “Endless Hours”, are suffused in barely veiled melancholy, while ambient forays like “Slow Fade” or “Illusion of Time”, with Alessandro Cortini, exemplify his elegiac sensibility and graceful touch.