LINCOLN, Maine — The screams of the truly terrified, Ruth Birtz says, are different from those of the merely surprised.

“The terrified screams are the most blood-curdling and [come] at the top of their lungs. The others come from within and are more, what’s the word, sinister,” Birtz said. “The terrified ones are more shrill. They have a shrieking quality to them.”

The town’s economic development supervisor, Birtz has become adept at telling one scream from another since town workers began hosting Haunted Hill, a haunted house at the Ballard Hill Community Center, last weekend.

Running from 6 to 9 p.m. Friday and Saturdays, until Oct. 29, with final showings at those hours on Oct. 30-31, the haunted house features six to 20 actor-volunteers whose sole purpose, Birtz said, is to scare your brains out.

Birtz and town events coordinator Amanda Woodard declined to say how many volunteers there are or exactly how they go about their duties. Revealing any of that, they said, would spoil the fun, but they hint that the concept of the whole house, as designed by former Town Council Chairman Steve Clay, a professional funeral home director, and executed largely by Woodard, is much more than typical Halloween ghouls and goblins.

The sophistication prompted Haunted Hill organizers to recommend against allowing children under age 5 to enter the house and to stipulate that children ages 12 and under be accompanied by an adult, Woodard said.

Admission for people age 13 and over is $5; 12 and under, $3.

Town officials opted to turn the center into a haunted house to make money for town events and get more use out of the aging structure. They hope that Lincoln will become well-known for Haunted Hill, Birtz said.

“Listening to the screams, really, that’s the fun of it,” Birtz said.