When Russell Crowe menaces Caren Pistorius for 90 minutes in “Unhinged,” the road-rage thriller set to open in U.S. theaters July 31, he will be accompanied by an angry, pounding soundtrack created by an English composer in the European principality of Andorra.

It was inevitable when the coronavirus pandemic struck Europe earlier this year, sending everyone into lockdown mode, that composer David Buckley was forced to collaborate with director Derrick Borte long distance: 4,000 miles — between Borte’s home in Virginia and Buckley’s studio in Andorra, located in the Pyrenees mountains between Spain and France.

Buckley’s wife hails from Andorra, and he moved his family to the tiny nation last August, planning a break from Los Angeles. He wrote much of his music there for last season’s “The Good Fight” on CBS All Access and “Evil” on CBS. While, for “Unhinged,” he met Borte in L.A. and first screened the film there in February, the score was entirely conceived and executed in Buckley’s European studio.

“My place in Virginia was command central,” Borte tells Variety. “Dave was eight hours ahead of me, so I would get up in the morning and work with him. By the time we would wrap things up, it would be time for me to call into editorial and sound and visual effects, all working on the West Coast. Then late at night I would do ADR with my actors, who were both in Australia.”

Reached in Andorra, Buckley characterizes the movie as “one man on a brutal mission to hunt down one woman,” and adds of the score: “It needed energy and momentum. Even though the film is concise, it’s a relentless ride when it starts.” So a traditional orchestra, despite Buckley’s roots in classical music, particularly that of the Renaissance era, was never seriously considered for this production.

Borte had more than music in mind. “I wanted to try and find unique sounds, things clanging together, buzzing, ringing in the ears,” says the director. “Rhythmically, we both agreed about not wanting this percussion to have any kind of groove; it needed to feel less musical and more sound design in some ways.”

Adds Buckley: “It was generally agreed that a synthetic, electronic soundtrack would supply the aggression. [Crowe’s character] becomes a beast about three minutes into the film, and he is unrelenting thereafter. My structure was to use his vileness and bestial nature as a sort of contour for what the music needed to do. There’s not one moment where I play anything sympathetic over him.”

Buckley’s dark, percussive, occasionally industrial-noise score dominates the film, although a calmer, piano-based motif for his terrified target sneaks through at rare moments to relieve the tension.

Notes Borte: “Dave’s work speaks for itself. He is great at composing music that enhances the material. The best scores work so well that you’re paying attention to the whole film. He’s a master at what he does.”

In Andorra for the foreseeable future, Buckley has also finished a choral score for “Greenland,” a comet-threatening-Earth disaster movie due Aug. 21, and is beginning work on “The Wheel of Time,” Amazon Prime’s forthcoming fantasy series based on the Robert Jordan novels.