When a scary movie franchise crosses over from the big screen to live theater, and the ghosts or shadowy whatever-they-ares are sharing the audience’s space, breathing the same air, the body responds.
Dread hollows out the chest. The skin prickles with fight-or-flight. And when a jump scare finally releases (some of) the tension, the internal organs curdle, like milk turning sour in the time it takes to gasp.
But at “Paranormal Activity,” which opened Tuesday, Feb. 24, at American Conservatory Theater’s Toni Rembe Theater, it’s a two-way exchange. As Lou (Cher Álvarez) and James (Travis A. Knight) hope a change of scenery in a new London home will improve Lou’s mental health, Gareth Fry’s sound design is a symphony of unease. The house’s radiator rumbles like a distant avalanche. A subwoofer’s thrum gradually crescendoes into brassy sirens and a firebreathing choir, speckled with yelps of pain and (a bit cheesily) evil laughs…