It’s six p.m., and I’m at John Marshall Media near Times Square in New York City, sitting in the recording booth where Kathleen McInerney has been narrating two audiobooks back-to-back for the past eight hours.

Glancing out from the booth into the studio on the spring day, I see McInerney clad in a grey hoodie, jeans, and sneakers. Around the microphone—which tilts down from above like in an old-timey radio studio—lays a handwritten list of the book’s characters, an iPad from which McInerney reads the text, and a bottle of water.

As I turn a bit to examine what’s on the table, she says, “You can’t really move or you go off mic.” I freeze in place, my shoulders stiff, wondering how she has been 1) sitting in the same position for hours on end, 2) alone in the booth with only occasional verbal directions from an engineer out of her line of sight, and 3) performing Save the Date by Mary Kay Andrews for one of the millions of audiobook fans who may never know how much work goes into the production of their favorite listening experience.

With One Narrator, Many Voices

“There’s nothing like being able to perform a play all by yourself. I get to do all the characters, set the scene – so all of my acting training comes into play every single day,” says McInerney.

Like many audiobook narrators, she studied acting and performed in theatre productions before exploring voice work. “As an actor, I’m not looking to limit myself to something that’s only in one genre. But it just happens that most of my work is in this area at the moment.” McInerney has voiced dozens of animated TV shows for children, and has narrated audiobooks for the past 15 years.

So when it comes to narration, McInerney is a pro. She has given voice to over 100 audiobooks and received nominations and awards from a variety of publishing associations. She won the 2013 AudioFile Earphones Award for the YA audiobook Just One Day by Gayle Forman. She was a 2011 Audies Finalist for In a Heartbeat by Leigh Anne and Sean Tuohy, and a 2009 Audies Finalist for Louise Erdrich’s Plague of Doves. McInerney has a few children’s audiobook titles under her belt as well, including One Year in Coal Harbor by Polly Horvath, a 2013 audio pick by the Association for Library Service for Children (ALSC) and the Young Adult Library Services Association (YALSA) for listeners 14 years old and younger.

“When you’re casting, a few names always float to the top,” says Macmillan audiobook producer Robert Van Kolken, who’s supervising the audio session that day. Looking at McInerney, he says, “You have a childlike voice, so that’s great for kids’ books.” But he says that she can tackle a broad range of characters thanks to her mastery of accents and timbre: “A wide spectrum is not typical of narrators.”

However, one challenge for McInerney has been reading aloud Linda Castillo’s Kate Burkholder books. The series includes Sworn to Silence, Pray for Silence, Breaking Silence, Gone Missing, and Her Last Breath. Castillo’s fictional work focuses on brutal murders that take place in an Amish community. Of reading the books, McInerney says, “I couldn’t go to bed—I was so scared! It’s the craziest thing I’ve ever had to do. It’s such a challenge.” But ultimately she says that the series is one of her favorite audiobook projects—and one of her most high-profile ones.

But she says that, of all things, one of the biggest challenges to narrating is what to eat. “This sounds boring, but you have to figure out what you have to eat so that you can keep your energy up but not have weird digestion.”

After the birth of her daughter, Rena, 15 years ago, McInerney took on more and more voice work. Rena, who sits in the corner of the recording studio doing her homework on her MacBook, deadpans, “You’re welcome.”

Big Hits and Big Challenges

According to their current catalogue, Macmillan will release 40 new audiobooks in fall 2014. The crop includes several nonfiction titles written and read by celebrity authors like TV host Pat O’Brien, legendary late-night personality Dick Cavett, and Oprah Winfrey.

Last year, Macmillan earned a Grammy nomination for one of its celeb audiobook titles—Billy Crystal’s Still Foolin’ ‘Em: Where I’ve Been, Where I’m Going, and Where the Hell Are My Keys? “He recorded part of it live at NYU,” says Laura Wilson, director of production at Macmillan Audio “We incorporated some of the live recording that he did into the audiobook.He’s a performer; he really wanted to have audience feedback.”

But whether the narrator is a celebrity or not, part of the audiobook production challenge is coordinating the process in the first place. Esther Bochner, publicity manager at Macmillan Audio, says of setting up recording locations, “We try to work it out with authors, with narrators based on where they’re going to be.” Elizabeth Warren, for example, recorded in D.C., while John Waters read in Baltimore, where he resides. “The producer will find a studio there and either travel down or an engineer in a studio there will work with them,” adds Bochner.

Another common challenge is getting an author who isn’t a seasoned performer to narrate his or her own audiobook. Though some authors embrace the experience, for others “it’s the first time they’ve ever read their work out loud,” says Wilson. “I think they’re surprised sometimes at how difficult it is to make things sound good just with your voice. And with being alone in the booth, it’s surprising how much effort you have to put in to maintain your energy to make something sound interesting.”

She continued, “When you start at 10 a.m. and you finish at 5 p.m., it needs to sound the same at 4:30 as it did at 10:30. I think professionals always have a bit of an advantage because they’re so used to it. Alone in the booth when you can’t see the person on the other side except when they push the ‘talk’ button, it’s really just hearing their voice in your head and just keeping yourself going, it’s something that takes practice.”

Engineering an Audiobook

Back in the studio, I watch McInerney narrate while I sit next to her daughter. Directly in front of us is engineer Mike Odmark, who dons headphones, monitors the recording, and operates the Yamaha soundboard as necessary.

As she narrates, Odmark listens closely for any flubs, skipped words, or stray noise. Every once in a while, he corrects her— “Actually, that was supposed to be ‘there’s’ ”—then he edits the clip and punches back in right away.

The recording process looks easy— if by “easy” you mean operating a desk-sized dashboard of sound equipment with two computer monitors atop it. But he assures me that the technical aspects are more intuitive than they used to be: “Now we use Reaper software, which is tailored to voiceover. We used to use ProTools, but that had too much firepower.”

He has worked as an audio engineer for about nine years and has been in the voiceover world for about two years. A seasoned narrator like McInerney can cover about 25–30 pages in an hour, though not all narrators can work as swiftly. Still, on average it takes about two hours to produce one hour of recorded prose. And once that’s done, someone does quality control to make sure the audio sounds polished and matches the text. Occasionally, they need to bring a narrator back in to rerecord bits and pieces, but the process with the Andrews and Castillo books so far, Odmark says, has been smooth.

But while most audio recording sessions end around 4 p.m., today the duo is doing back-to-back sessions from 10 a.m. to 3 p.m. and then 4 p.m. to 10 p.m. McInerney says, “It’s just that everything just happens to be due right now.”

Wilson says that, when it comes to audiobook production, “I think people often focus on the voice, and it’s a lot more than the voice.” Improved technology makes the process more efficient, and therefore audiobook publishing houses are more prolific. But ultimately, she says, “Creating audiobooks hasn’t changed that much. You’re still dependent on having a really good reader reading the story. Reading it aloud brings it to life in ways you didn’t expect.”

Grace Bello is an editor at Guernica and a lifestyle and culture reporter based in New York.