Sound producer Greg Smith catalogued his recordings as part of a master’s thesis. After I finished this project,” he said, “I thought, ‘It doesn’t make sense to me to return it to a shelf.’ (Dayna Smith/FOR THE WASHINGTON POST)

A baby panda in the wild sounds like the high-pitched bark of “Paris Hilton’s Chihuahua.”

Humpback whales mating off the coast of Maui moan amidst the distinct sounds of air bubbles popping underwater.

The futuristic grunts of aliens you might have heard in “Stars Wars: Revenge of the Sith” were not created in the studio but were actually made by buffalo grazing in South Dakota.

These sound clips and more than 1,500 others were donated last week to the library at American University by sound producer Greg Smith, who spent more than 30 years traveling the world for film and radio, working for major production companies including NPR, National Geographic and Imax.

The collection includes Smith’s best hits and are immediately accessible to film students, other aspiring filmmakers and “anybody with access to the library,” says Robin Chin Roemer, communications librarian at American. “We are really happy to have this collection. Not all of us are jumping outside to record sounds around us, but Greg did.”

Smith, 55, of Rockville, worked for Lucasfilm on features including “Indiana Jones and the Last Crusade,” “Jurassic Park” and the “Star Wars” series. Along the way, he collected thousands of extra sounds.

As an adjunct professor at American, Smith says, he was constantly hearing from film students who wanted his advice on getting authentic sound effects. Many of the clips in his collection are hard to obtain. If a filmmaker wants the sound of a panda, he might try to fake it. “But I have 21” authentic panda tracks, Smith says. “I have pandas in there grunting.”

A composer who also runs a film and music production company called Pros From Dover Productions, Smith catalogued the clips as part of his master’s thesis at American. It took more than a year to isolate and label sounds from more than 800 hours of tapes.

“It was a tedious process,” Smith says. “After I finished this project, I thought, ‘It doesn’t make sense to me to return it to a shelf. . . . A sound effect is a living thing. It runs, pops, squeaks, rumbles, roars. For it to sit on a shelf in CDs and collect dust doesn’t make sense.’ ”

The donated tracks vary from ambient noises to space shuttle launches to the second and third takes of an actor saying, “Gee, these pretzels are making me thirsty.” The collection includes the driving sounds of jackhammers, the click of a single toucan and the roar from the inside of a NASCAR racecar speeding at 160 mph, the maximum speed at which Smith felt himself safe to drive.

He wanted to capture what a speeding car sounds like — from inside. He tried putting recording devices in cars with professional drivers, but the sound never came out quite right. He decided to drive a racecar himself, after training. The hollow, echoing sounds of cars zipping around a track had always intrigued him.

“When I was growing up” in Bethesda, “I thought, ‘What is the big deal with NASCAR?’ ” Smith recalls. “The first day on location” for the Imax film “NASCAR 3D,” “I walked into the Daytona 500. Maybe 100,000-plus people are screaming and it’s 43 cars going at top speed. I remember saying to myself — not that anybody would have heard me — ‘Now I get it!’ The sound in the stadium is big enough to rattle your chest.”

Pen and paper do a disservice to sound. In a lecture hall at American, the sounds of Smith’s collection mesmerize his audience: the humpback whales, the sound of thunder isolated from the fall of raindrops. For three weeks, he sat on top of a mountain in New Mexico waiting for the perfect thunderstorm to record for an Imax film called “Blue Planet.” “It’s really hard to get thunder,” he says, “unless you can get it before the rain starts or just after the rain stops.”

On the mountain, winds blew and lightning struck so close that “you expected to see Charlton Heston standing with his staff,” Smith explains. “These were great thunderstorms. Lightning crashed! ‘Boom!’ I learned after the first couple of ones not to say things like ‘Wow!’ because it screws up the recording.”

The booms of thunder on the sound clip are big and familiar but so irregular that they take listeners by surprise, anyway.

Smith prepares to play the next clip. Just then the thunder crashes again from a clip that Smith did not anticipate. The audience laughs.

Smith clicks a button, and out comes another sound: the baby panda, “about the size of a pillow,” on a mountain in China. Whatever you’d expect, it doesn’t sound like that.

“It sounds more like the high-pitched bark of Paris Hilton’s Chihuahua,” Smith says.