LOS ANGELES — Having tried 3-D films, earsplitting sound systems and even alcohol sales in pursuit of younger moviegoers, some theater chains are now installing undulating seats, scent machines and 270-degree screens.

For an $8 premium, a Regal theater here even sprays patrons with water and pumps scents (burning rubber, gun powder) into the auditorium. Can’t cope with two hours away from your smartphone? One theater company has found success with instant on-screen messaging — the texted comments pop up next to the action.

“When I step back and think about what will get people off a couch, in a car, down the road and into a theater, the answer is not postage stamp-sized screens and old seats,” said Gerardo I. Lopez, the chief executive of AMC Entertainment, the No. 2 chain in the United States. “Why would they bother? What the hell, stay in the house.”

If Mr. Lopez sounds frustrated, he is. Ticket revenue in North America has fallen 4 percent this year compared to the same period in 2013, according to box office analysts, and attendance is equally down. The busy Thanksgiving and Christmas moviegoing periods are not expected to make up the ground.