Sydney producer Christopher Emerson, aka What So Not, balances concussive beats and roller-coaster drops with relatable emotional drama on his second album. That human element is made clear right from his rising, mantalike singing on opener “Alive,” inspired partly by the loss of The Prodigy’s Keith Flint. Emerson also uses guest vocalists as high-precision tools on this festival-ready follow-up to 2018’s Not All the Beautiful Things. A warbled vocal hook and bratty rap turn by Oliver Tree offset Killer Mike’s languid-turned-rapid throwdown on “Mr Regular,” while “Messin’ Me Up” flexes an emotive narrative from Brooklyn singer EVAN GIIA and “Mercy” marks a soaring reworking of Emerson’s 2018 team-up with Danish singer MØ. There are nuanced moments among such stark peaks, though, and the guest-stacked “On Air” even features a toy saxophone that Emerson happened to stumble across. That sense of playfulness pervades this album, as the consummate collaborator opens himself up a thrilling range of modes.