Whereas print books allow the reader the familiar heft of a novel, minimal eye strain, and the chance to inspire literary Missed Connections on Craigslist, and e-books offer a lightweight way to download up to 3,500 titles lightning fast and read everything from e-Fifty Shades of Grey to e-Think Like a Man without attracting undue attention, audiobooks aim for a different niche in the market.

Sure, audiobooks are for those who want to “read” while tidying the house or driving or hitting the treadmill, but they’re also for an audience that seeks an experience that mere text or pixels can’t convey—including the feeling that the author or narrator is speaking to them in their living room, car, or the cardio machine in the gym.

Publishers increasingly offer audiobook extras—everything from original music to exclusive author interviews. “We’re not out to compete with any of the other formats,” says Anthony Goff, vice president at Hachette Book Group. However, audiobook publishers must create a unique experience for customers, who usually shell out more for the audio than they do for the print edition—and sometimes three times as much as for the e-book. But for publishers, it’s often a struggle to make those audiobook extras happen.

When it comes to crafting an aural experience, audiobook publishers rely on original music, sound design, and more to distinguish their offerings from the print-book experience.

Tantor Media marketing manager Allan Hoving says, “We have a book called Roam [by author and Hollywood composer Alan Lazar], which is a novel with music, so the author of that book actually composed seven unique compositions to accompany the novel. Obviously, you can’t include that in the written version.”

Whereas the print version of Lazar’s heartstring-plucking narrative about a dog searching for his family will easily pique the interest of pet lovers, the hardcover, and ensuing trade paperback coming out this August, lack the boon of Lazar’s musical talent: he has scored over 30 films and TV shows. His piano compositions on the audio add a cinematic touch. Hoving says that the author “always meant to have a soundtrack, if you will, to the book, which I think is a great concept.”

Similarly, 2010 Audie Award finalist The Music Lesson by Grammy-winning bassist Victor L. Wooten offered not only narration but also music. Wooten’s story, melodies, plus a bonus performance by fellow Grammy-winning jazz musicians Bela Fleck and the Flecktones, created a full sonic storytelling experience for the listener at only $29.99.

Hoving says of getting Bela Fleck and the Flecktones to sign on for the audiobook: “It was something that the author had wanted to do and was able to help make happen. Oftentimes, if you [as the publisher] are just trying to license a variety of music, it turns out to be very difficult.”

When it comes to celebrity memoirs produced by larger publishers, however, the star’s connections or willingness to provide music eases the production process. Megan Fitzpatrick, associate director of marketing and publicity at Hachette Audio, says that Tina Fey’s Bossypants, a 2011 Audie finalist, included a Hollywood soundtrack: “Her husband is a composer and musician. He did the music for 30 Rock, and he actually did the music for our audiobook.”

Carole King’s audiobook A Natural Woman, which came out in April, boasts an original piano piece and a cappella performances. The songs were recorded at Hachette’s studio in New York City. For big publishers like Hachette, Goff says, the conflict lies in “timing and availability.” Though Hachette lucked out with the schedules of Fey and King, Goff says, “Once you start talking about A-list celebrities, it sometimes can become an impossible project to finish in a short amount of time.” Michele Cobb, president of the Audio Publishers Association, agrees: “Oftentimes when you’re dealing with a big celebrity, their time is pretty precious.”

More than original music, author interviews appear frequently as audiobook extras. Says Cobb, who also works in sales and marketing at AudioGO, “I think those behind-the-scenes q&a pieces with an author or narrator are something that we see more and more of in the industry in general.”

“The interviews have become more and more of a standard practice here,” Hoving says. “I have conducted now about almost 50 of these interviews, and we use them not only on the audiobook product, but also as a promotional tool” across Tantor Media’s Web site and social media channels. Fortunately, author/narrators, including Animal Planet’s Pit Boss star Shorty Rossi, author of the January release Four Feet Tall and Rising: A Memoir, can make the trip to Tantor’s studio in Old Saybrook, Conn., to record books and stick around for a q&a. But if not, Hoving says, “We do them as phone interviews. We try to work with the author to use landlines and get the best audio quality that we can. The other day I did an author interview, and the author was in Bangkok.”

In some opportune cases, it’s the publisher who travels to record the author. AudioGO, as its company name suggests, will take its recording equipment on the road—to Martha’s Vineyard, for example, as it did to create an audio-exclusive, digital-only companion guide to TV chef Steven Raichlen’s June fiction release Island Apart. The digital guide—Steve Raichlen’s Martha’s Vineyard: Food and Recipes from Island Apart—is “going to be basically a cooking show for audio,” says AudioGO executive marketing manager Tara Gelsomino. “We’re going to go [with Raichlen] on a walking tour of farms and local farmers’ markets and seafood stores. And we’re going to go to his house on Martha’s Vineyard and record him while he cooks a whole meal from the book. He’ll discuss why the food and the preparations are important to the characters in the novel. It will have all the sounds of him cooking as well as his own stories about growing up on Martha’s Vineyard.” Here, the publisher takes the exclusive author interview a step further and captures him amid the sounds of his natural habitat, the kitchen. “It’s a real expansion of what the fiction piece offers you,” says Cobb.

Tantor’s Code Talker audiobook, released last December, also adds a new dimension to the text. The audio edition of this memoir by Chester Nez, one of the original Navajo code talkers from WW II, harks back to a piece of American history: “We have not only the PDF of the code but an interview with the author who is, I believe, the last remaining code talker from the original group,” says Hoving. “He speaks in the code during the interview and uses one of the famous messages that he transmitted.” As with Tantor’s banner release last year, AudioFile Earphones Award–winner The King’s Speech, which included a recording of the titular speech given by King George VI on September 3, 1939, the publisher leveraged the audio format by including the sonic moments that shook the world.

But securing audio extras gets trickier when it comes to the elusive celebrity narrator. Because A-listers are short on time and recording an entire audiobook can take days out of a celebrity’s schedule, it’s tough to secure a well-known personality to record anything other than his or her own audiobook memoir. In fact, Oprah Winfrey declined to narrate the 2008 audiobook edition of To Kill a Mockingbird by Harper Lee—though the honor later went to Lee’s personal pick, Sissy Spacek.

However, for Stephen Colbert’s May children’s book release I Am a Pole (And So Can You!), certainly Hachette wasn’t able to simply book a top Hollywood actor to record the audiobook just like that, right? Actually, Hachette did.

Says Goff: “We were fortunate enough that Stephen called in a favor and asked Tom Hanks to read.” This cheeky children’s audiobook, inspired by a January conversation on the Colbert Report between Colbert and Maurice Sendak, features Hanks’s narration with “interruptions” from author Colbert. Says Goff, “Our goal in audio is to be simultaneous [with the print edition] so we can take advantage of all the print and the publicity and the advertising. This book was just added on to the Grand Central Publishing list late, so if it weren’t for Stephen and Tom’s availability to come on a moment’s notice and record this, it would have been a lot more difficult [to meet our release date]—if not impossible.”

According to Cobb, “Audiobooks often follow the same standing as the New York Times bestseller list [for print books] because those titles are getting a lot of focus. And then you have things like Bossypants, where it’s read by the [celebrity] author, so that really brings another boost to it. Oh—,”—she pauses—“and then there’s of course the Samuel L. Jackson recording of Go the F*** to Sleep [from Brilliance Audio, released in June 2011]. So here it is, an interesting book, and you get someone you really want to hear record that. Finding the right narrator can often be an extra unto itself.”

If audiobook sales are driven by the same forces as book sales—TV, magazine, and blog coverage, advertising, and prominent book reviews—then what’s the motivation to create these original soundtracks, exclusive interviews, these celebrity recordings? “We’re not exactly including this bonus material to sell,” says Fitzpatrick. “We’re including it to make the experience better.”

Grace Bello is a freelance writer in New York.