Respeecher Brings the Voices of Ernest Shackleton and His Crew to Life for National Geographic's "Endurance"

Respeecher helped in bringing history to life by reviving the 100-year-old voices of Sir Ernest Shackleton and five of his crewmates for Endurance, a National Geographic documentary. Through cutting-edge AI voice cloning for documentaries, Respeecher enabled audiences to hear the explorers' words as if they were spoken by the men themselves, creating an unparalleled immersive experience.

Volodymyr Ovsiienko, Respeecher’s Business Development Executive, summarized the cooperation:

“When the "Endurance" team first contacted us back in 2022, they weren’t sure we’d take on this project, as one of the source records was stored on a wax cylinder - a very unusual medium. However, we gladly took up the challenge.

After hard work and dozens of experiments, we created Respeecher-level conversions, and let the viewers hear the voices of the crew members of this truly unique expedition.”

Who is Ernest Shackleton?

Ernest Shackleton, an Anglo-Irish explorer, led the Trans-Antarctic Expedition in an ambitious attempt to achieve the first land crossing of Antarctica. The story of how Shackleton and his men escaped has become legendary. Among shipwrecks, it is the most famous of the unsolved.

In 1915, the Endurance was crushed by ice floes in the Weddell Sea and sank at a depth of about 3 km. Shackleton and his crew were forced to escape in lifeboats, in which they made an unprecedented journey across the Southern Ocean. Shackleton's story is one of the most extraordinary stories of the "heroic age" of Antarctic exploration. The Endurance ship got stuck in the ice off the coast of Caird and drifted for 10 months before being crushed by pack ice.

A century later, the Falklands Maritime Heritage Trust successfully discovered the Endurance wreck, inspiring National Geographic to produce a documentary capturing this historic moment. To enhance the film's authenticity, the production team sought to include journal entries read in the authentic voices of Shackleton and his crew.

The Challenge: AI-generated Historical Voices

Recreating Ernest Shackleton's AI voice presented a unique challenge. Since the Trans-Antarctic Expedition took place in 1914, there were no “conventional” audio recordings of the voice of Sir Ernest Shackleton on tape or digital device.

To bring his voice back to life, Respeecher had to work with a scarce and challenging source: wax cylinder recordings. Unfortunately, the records made on wax cylinders were very short.

Natalia Statyvka, Head of Delivery, reflected on the difficulty of working with such an unconventional medium:

"This was our first time handling wax cylinder recordings, and it pushed our expertise to new limits. But if Sir Shackleton never gave up, how could we?

Our sound engineers dedicated themselves to ensuring the crew's firsthand accounts were heard exactly as they would have sounded over a century ago."

The Process: Endurance Documentary Voice Recreation

Endurance documentary voice recreation was a complex and highly collaborative effort. Our experienced sound professionals worked closely with the movie production team to ensure historical accuracy and emotional depth in the recreated voices. This was not just a matter of pressing a button—achieving the final result required extensive brainstorming, leveraging the expertise of multiple specialists, and going through countless iterations of feedback and refinement.

Having previously collaborated with documentary directors Elizabeth Chai Vasarhelyi and Jimmy Chin on Nyad, an inspiring biographical sports drama, we understood the precision needed for Endurance. Every detail mattered, from the pacing of speech to the nuances of tone, to create an experience that felt as immersive and authentic as possible.

To achieve this, we relied on the talent of skilled voice actors. While AI technology plays a crucial role in voice cloning for historical figures, it does not generate a performance on its own. Voice actors studied the speech patterns of Shackleton and his crew, reading their diary entries while mimicking their style and intonation.

Dmytro Vasylets, synthetic speech artist who worked on the project, described the challenge of working with such limited and aged audio recordings:

"To train the AI model, Respeecher typically requires around 30 minutes of voice recordings to achieve the highest possible quality. However, for Endurance, some recordings were shorter than a minute. Despite these challenges, we applied all our expertise, knowledge, and the latest AI-powered tools to generate the best possible speech reconstruction."

His colleague Anton Prykhodko further explained the process behind recreating Shackleton's voice:

"Training the AI model on Shackleton's voice took nearly a month due to the recordings' poor quality and extreme age. Once the AI model was trained, we worked with talented voice actors who brought the voices to life by reading the lines to capture their speech style and personality. AI alone does not create a performance—it takes hours of voice recording, meticulous editing, and human dedication to make these voices sound as real and compelling as they did 100 years ago."

The Result

Respeecher successfully created a compelling and immersive voiceover for Endurance, adding a deeply personal touch to the documentary. The National Geographic AI voice tech team was highly satisfied with both the process and the final result, which debuted to great acclaim at the London Film Festival.

Recreating these voices was a technical achievement and a bold artistic decision by the filmmakers. By using AI to bring historical figures back to life, Endurance offers a rare opportunity to hear the speech patterns and personal expressions of men who lived nearly a century ago, making history feel more tangible and immersive than ever before.

Director Elizabeth Chai Vasarhelyi, in an interview with Deadline, expressed her amazement at the authenticity of the recreated voices:

"Their personalities really come out through their diaries. Now we have this tool that's available, if you have a small recording of someone's voice, you can use their words in their own voice. I didn't know what the net effect was going to be, how it would actually feel. And then it was like: 'Oh my God, it's them.'"

Volodymyr Ovsiienko shared his experience:

“I was present at the premiere of the “Endurance” at the IBF London Film Festival. The reception by the audience was extremely positive - the feeling of strength, perseverance, and working towards a common goal against all odds didn't leave a single viewer indifferent. I am extremely proud that Respeecher was a part of this project.”

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Respeecher voice restoration technology is not just for historical documentaries—it can also create Hollywood-quality voiceovers for films, animations, video games, and more.

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