Excavating a media history of loudspeakers and open-air cinema in Maoist China, this talk proposes a new conceptual framework of  “socialist hot noise” to describe a participatory sociothermic affect and a synergy between body and electricity that soldered scattered populations into the “revolutionary masses.” Drawing on archives, gazetteers, memoirs, and oral histories, the first half examines the state-sponsored development of loudspeaker networks as well as grassroots listening experiences and practices, from broadcast rallies to rooftop broadcasting, from labor competitions to quasi-karaoke, from enhancing the Mao cult to engendering violence and terror. The second half discusses open-air cinema as a “hot noise of attractions” that generated revolutionary energy through “cinematic liturgies” led by mobile projectionists before, during, and after screenings.  I argue that Maoist cinema was a “physical and spirit medium,” whose improvised and impoverished infrastructure contributed to the Mao “cult,” converted skeptics of communist “miracles,” and “exorcized” class enemies.  The conclusion addresses the revival of loudspeakers and open-air cinema in a postsocialist media ecology.