For more than a decade, sound mixers Kevin O’Connell and Greg P. Russell worked hand-in-hand on some of the industry’s biggest box office hits, movies like “The Rock,” “Armageddon,” “Spider-Man,” and “Transformers.” It was a relationship born out of an early coupling on Ridley Scott’s “Black Rain” that later took flight in the mid-1990s when the two set up shop together at the Cary Grant mixing stage on the Sony lot in Culver City. In their time together, they landed Academy recognition 12 times, quickly becoming the Susan Luccis of the Oscars — consistently nominated, but never awarded.

Ten years ago, after the first “Transformers” film, O’Connell and Russell went their separate ways. This year, they’re back at the big dance together, though for different projects: O’Connell picked up his 21st nomination to date for Mel Gibson’s “Hacksaw Ridge,” while Russell is back in the hunt for the 17th time with Michael Bay’s “13 Hours: The Secret Soldiers of Benghazi.” But both mixers look back fondly on their run together as one of the most electrifying periods of their professional lives.

“Those were the glory years of our business, just based on budgets and how post is handled now,” Russell says. “But they were some of the best years of our careers. I’ll inevitably see a movie we mixed come on the television — ‘Enemy of the State,’ ‘The Rock,’ ‘Pearl Harbor’ — and will just reminisce.”

O’Connell concurs, adding that in the pre-internet days of old, the way you would hear you were nominated was your phone would ring at 5:30 in the morning. “I would immediately call Greg and you’d have to peel us off the ceiling — we’d be so excited,” O’Connell says. “When the nominations came out this year, my first call was to him.”

Now they’re up against each other for the first time, with a pair of very different war films — a World War II drama from an embattled director making his return to the director’s chair, and a modern warfare saga from one of the most high-octane filmmakers in the business.

For O’Connell, it’s his first trip back to the Oscars since his last nomination with Russell, for “Transformers,” a decade ago. But getting back in the saddle with Gibson has been a joy.

“I think he’s one of the greatest storytellers of our time,” O’Connell says. “He’s a very emotional director. I’ve seen him go through many changes over the last 10 or 12 years and the Mel that I worked with on this film was the strongest, coolest, most vibrant Mel I’ve ever worked with.”

It was also the first time O’Connell could really sink his teeth into a full-blooded war film, notwithstanding elements of “Rambo: First Blood Part II” and “Pearl Harbor.” And it was, like “13 Hours,” a reality-driven affair that puts the viewer smack dab in the hell of war.

“You’re in the trenches, on the battlefield, with explosions and artillery fire all around you,” O’Connell says. “The first barrage was 10 solid minutes with no music. The nickname for that battle was ‘The Typhoon of Steel,’ because they were constantly being barraged by artillery fire. This was fantastic for us to do because 90% of the track is 100% choreographed by the sound team. You couldn’t do much with the production sound because the explosions were propped and the guns sounded like cap guns. So everything had to be manufactured by the sound team.”

O’Connell, who spent years mixing effects, transitioned to the dialogue chair later in his career. Typically a post-production sound team involves one mixer handling effects, another handling dialogue, and another handling music, though dialogue and music have been coupled more and more in recent history. The dialogue mixer tends to “run the room,” so to speak, and O’Connell was attracted to that challenge when his career went into its second decade.

Russell, meanwhile — who has picked up nominations for two “Transformers” sequels, 2010’s “Salt,” and 2012 James Bond hit “Skyfall” in the years since his partnership with O’Connell — comes from a long history of mixing music. He could lend his expertise to O’Connell early on, while also learning from O’Connell’s deep well of knowledge on effects.

“Our backgrounds helped each other to develop our unique skill sets,” Russell says, adding that Bay is particularly fond of a robust, old-school, three-person mixing team. “Michael likes barking out, ‘Raise the music here, raise the dialogue here.’ He likes what I call ‘all hands on deck,’ so he can get things done immediately.”

However, “13 Hours” was a very different film for Bay. It wasn’t meant to be the sort of heightened realism of the actioners that made him a household name, but rather — like “Hacksaw Ridge” — an authentic depiction of a hellacious battlefront. However, it wasn’t the expected sonic elements that were crucial to that direction.

“Michael wanted this film to be a gutsy, boots-on-the-ground, honest depiction of what happened there in Benghazi, but this was not sensationalism,” Russell says. “The rooftop sequences and all of the bullets and impacts, the ferocity of what those exchanges were, are very intense. But more importantly for us was that the emotional component on the film be equally strong. Pietro Scalia, our film editor, paced the film in such a way that there were moments to reflect, like, ‘What’s going on here?’ That’s one of the distinguishing aspects of Michael treating this movie differently. He wanted you to feel what these soldiers were feeling, that they’re reflecting on their children and families and ‘why are we even here?’ Those were as important as getting the skirmishes right.”

Since O’Connell and Russell’s partnership dissolved, both mixers have taken note of how the business of their discipline has shifted, even in just 10 years. Technology has made it easier to consolidate tasks, and as O’Connell puts it, it has become “a du jour business — you pick a sound supervisor, then you pick a mixing crew, and the mixing crew isn’t just a sound team anymore. Then you pick a facility and you just put a deal together. It’s not like the old days.”

Russell, meanwhile, views the aforementioned consolidation as a double-edged sword.

“There is a cross-section of sound editors participating in the preparation of the material that allows them to do quite a bit of mixing in the box,” Russell says. “But I stand behind what we who have been doing this for over 30 years bring to the table, the experience and cinematic sensibilities we bring mixing over 200 movies, versus the guy who has done four or five movies. Just having the tools doesn’t necessarily mean it’s the best way to handle each job.”

Adds O’Connell: “Budgets have changed a lot so we’re having to do more for less,” O’Connell says. “If you’re a homeowner and you want to build a $100,000 wall, but you only have $30,000, you get a $30,000 wall. Well, if you want someone to do a $100,000 sound job but you only have $30,000, you’ll get a $100,000 job, because they won’t settle for giving less than 100%.”

And what did the former partners think of each other’s Oscar-nominated work this time around?

“They did an amazing job,” O’Connell says. “Plus you’ve got two of the best sound designers working today, Erik Aadahl and Ethan Van der Ryn. I believe that they’re just a terrific team.”

Meanwhile, Russell says, the minute he saw “Hacksaw Ridge” he knew it would be in the mix — so to speak. “I said, ‘That’ll be there this year,'” Russell recalls. “It was a first-class job on a fantastic movie.”

Now they head off to the Academy Awards for their 21st and 17th trips, respectively, perhaps only to watch a musical (“La La Land”) waltz away with the big win, or perhaps not. That wouldn’t be anything they haven’t weathered before: “Chicago” toppled “Spider-Man” in 2003, while “Dreamgirls” beat out “Apocalypto” four years later. Indeed, there’s very little O’Connell and Russell haven’t experienced on Hollywood’s big night, short of finally hearing their own names called.

“Sitting in those seats at that show, with that combination of nominations — it’s a pretty unique perspective that we have,” O’Connell says.