Kroneck creates drafts in air-tight houses by cutting narrow slots in cardboard or foam core and positioning quiet fans behind them at various points along the path. Increase the effect with a fog machine.
Youtube is lousy with looped Haunted House music, but both Dahl and Kroneck prefer less obvious background noises – either ambient outdoor sounds like crickets and wind, or simply long stretches of silence punctuated by loud bangs. In both cases, cheap Bluetooth speakers are your friend.
Sudden changes underfoot are unsettling. Kroneck uses piles of dry leaves, peanut shells or bubble wrap. "Not everyone will step on them, they're just little land mines that some people run into," he says.