My grandmother was a diva at the Paris Opera. My father was a trumpet player – he even played with the Glenn Miller Orchestra on one occasion. But then the war happened and he became a CIA agent. I was born in Langley, Virginia, the headquarters for the CIA, but soon after that I was shipped out to Cairo and then grew up in Beirut.

Beirut was where I was introduced to classical music. I heard Carmina Burana on the gramophone, and also La mer and Daphnis et Chloé, plus every form of Stravinsky. Meanwhile, my father was into big-band jazz. He filled the house with instruments, which my siblings ignored. But I’d play them all and my dad noticed: finally, one of his children had the bug!

‘Rock musicians use their ears, they make campfire music – that’s how music is supposed to be’

The Arabic rhythms I encountered really struck me. There’s a Lebanese dance where they ignore the first beat and land hard on the three, and every eighth note is an up-chik [an upward-stroke guitar chord played on the offbeat]. Later, I discovered that reggae has the same foundation.

My father was raising me to be a jazz musician, but then I heard Hendrix and everything changed. It was the rage of rock music that appealed. You’re 16, you only have three hairs on your chest, your voice is about to break, you feel like you should be master of the universe but you’re just a pipsqueak. Drums seemed like a manly instrument to play.

When I went to boarding school in Somerset, I was the only drummer. I was in the school band and they kept firing me for being too loud. It was during this time that I had my first profound musical epiphany. We had our Christmas service at Wells Cathedral and hearing a thousand voices raised in song made me think: this is what music is all about.

There are two kinds of musicians: of the ear, and of the eye. They’re separated at birth but there are crossovers (like the brass players who improvise but can also read the dots on the page). Rock musicians use their ears, they make campfire music – that’s how music is supposed to be. Classical musicians connect to the music via the visual instructions on the page; with a schematic [score], you can do incredible things.

Composing for film was what took me back to the page. Francis Ford Coppola asked me to write music for his film Rumble Fish and the result was a little out of the ordinary. During the process, Francis said to me: ‘This is all wired and cool and hip, but it needs strings.’ So 20 guys turned up, and they played their parts so quickly that they were done in an hour. Since then, knowing what these trained musicians can do, I’ve been reaching into that toolkit more and more.

Ben-Hur began with a phone call. I was asked to score an arena production complete with chariot race, horses and thousands of underpaid Ukrainian extras. The show opened at the O2 and ran its course. Later, my manager told me to check out the 1925 black-and-white silent-film version, made 30 years before the Charlton Heston one – it took two weeks to defrost the celluloid print. I spent two years curating it, and then I had to chop my music to fit.

The orchestra is a complicated beast and there’s still so much to learn. I’m not a classical composer, but I use the orchestra to do what I want to do. When the RLPO commissioned me to write a percussion concerto, I was on the programme with some of the greatest British composers: Elgar, Walton, Britten and then my skinny little piece! But I was proud to be on that bill and actually it did pretty well.

At home, I groove along to the radio. I listen to Shirley & Spinoza – they play everything from the Beach Boys to ’50s radio plays with concrete music. Budding composers ask me: ‘How do I find my own voice?’ The answer is, you must open your mind – and listening to eclectic music helps me do that.

This article originally appeared in the February 2017 issue of Gramophone. Never miss an issue – subscribe today