WATERLOO - Performing a musical is the opposite of peeling an onion.

Instead of peeling layers away, the show is built up, layer by layer.

Cast members have spent the past month rehearsing for the upcoming Waterloo Community Playhouse production of Disney's "High School Musical." Some attended pre-audition classes.

The first two weeks they worked on singing and dancing. Then, they added dialogue and props.

In the coming days, an orchestra of five musicians below the stage will replace the piano. Next comes lights, sound, costumes and makeup.

On Tuesday, director Chuck Stilwill jotted down notes from the back of the theater during the first run through of Act 1. He, along with choreographer Shawn Jones and music director Julie Thomas, later offered a critique.

More facial expressions, Jones emphasized.

"Like me being bored like this," he said, propping his fist under his chin. "Back there it just looks like I'm being blank. What you think reads in normal life does not read onstage. Your excitement has to be so much bigger."

No two know that better than Chase Miller and Jackie Kehoe, who play Ryan and Sharpay. They have added a personal touch to line delivery, postures and walking to set their performance apart from features in the movie version of the musical.

"There's a lot of things people expect coming into it, but from an acting standpoint, it's finding that line between what's in the movie and staying away from things that have already been done," Miller said. "We didn't want to be (Hollywood stars) Lucas Grabeel and Ashley Tisdale."

With 44 people onstage, hygiene has been good, actors joked. They're learning to avoid collisions with props and each other, said Alyssa Gruye, who plays a cheerleader.

"My partner's gotten hit several times," she said. "Everything has to be so precise."

Another 20 people work behind the scenes, including the stage manager and crews, Stilwill said.

That makes controlling volume backstage difficult. Younger kids can be especially chatty, said Alta Schwab, who plays Cathy, so Stilwill asks for no talking or cell phone use for those on standby during a performance.

While soloists are typically challenged to be louder, projecting voices during group songs hasn't been a problem, Schwab said.

"They're usually telling us to sing quieter," she said. "These are fun, upbeat songs, so it's easy to just start belting."

After all, every ounce of pep needs to be reserved for the show. Endurance is key to having an ending as strong as the beginning.

"For our finale you have to have that energy all the way through," said Kelsey Athey, who plays a performance arts kid.