When an actor’s performance demands your attention the way it does in Denzel Washington’s “Fences,” getting the dialogue right is the key to clarity.

Production sound mixer Willie Burton and re-recording mixers Scott Millan and Gregg Rudloff had nothing to hide behind —  there were no action sequences (unless you count a garbage truck driving down the street in Pittsburgh), no visual effects, no guns shooting, and no pre-recorded singing. What little music there was on the track usually played through a radio. From the first frame, the audience is hit with a paced vernacular that needs to be clean, clear, and measured by the mixers.

“Fences” is based on August Wilson’s play about sanitation worker Troy Maxson (Washington) who tries to be a good husband to Rose (Viola Davis) and father to his children. But he drinks too much, and resentfully wallows in memories of his tough upbringing and his days as a baseball player, all of which lead him to make decisions that rip his family apart.

When Burton returned the phone call to exec producer Molly Allen about the job, Washington answered. “Denzel laughingly said he was doing everything on the film, even being the secretary,” Burton says.

Having read the script, Burton knew the project was going to be a big challenge because of the amount of dialogue. He traveled to Pittsburgh to prep the practical sets.

“The house we shot in and around was small,” notes the mixer. “And we didn’t break scenes up in four or five pages. Denzel wanted to see how far we could go, and we wound up going pretty deep. I would have 10 or so pages on my cart I needed to follow and mix.”

For the longer takes, the sound department used up to two booms to follow actors entering and leaving the set, and deployed wireless mics as another level of safety for the recordings.

Production removed windows from the living room to create shooting space, and even put fake owls on the roof to scare away birds for a cleaner production track.

Washington provided the crew with complete blocking and rehearsal.

“I have to give Denzel a lot of credit,” Burton says. “He comes [to the set] before anyone else and is already prepared. He allowed us to see a scene in its entirety. He is aware of sound and wants to make sure you get what you need. ”

In creating the final track, the guiding spirit for the re-recording mixers was being true to the words of Wilson, says Millan. “It was about making sure the dialogue worked and everything else fit,” he explains.

Adds Rudloff: “We were very careful as to what sounds we introduced into the film. We didn’t want to distract. It’s a very powerful movie with powerful performances. We could have harmed it if we weren’t cautious in our approach.”