It was Shakespeare who decreed that music should be the food of love. But even the Bard himself might be mildly surprised by the number of notes which have been cooked up, over the years, by his torrid tale of star-cross'd lovers. Just about everybody seems to have a musical take on Romeo and Juliet. Prokofiev produced a barnstorming ballet; then, out of the same Shakespearean hat, two suites and a set of piano pieces. Berlioz wrote a symphony, Bellini and Gounod operas, Tchaikovsky a fantasy-overture . . . and didn't Dire Straits whip up a moody, muddy piece of star-cross'd bombast, once upon a time?

But when Stephen Edwards set out to compose his own music and sound score for a new production of the play which opens tomorrow at the Pavilion Theatre in Dun Laoghaire, he didn't take any of those, thanks very much. "I only just recently listened to Prokofiev's ballet score," he confesses. "I mean, I recognised snatches, but I hadn't heard it in full before. I don't listen to other music to get inspiration for a piece. When I'm writing I don't listen to any music anyway, because it kind of feels alien."

An apt choice of word, perhaps. By the look of the serried ranks of electronic gizmos and discreetly blinking digital readouts which make up the Pavilion's space-age surround-sound system, theatre music has come a long way from the days of Shakespeare's raggedy bands. But it's still music. "Listen to this." In his tiny music room high above Dun Laoghaire harbour, Edwards plays an arpeggio on the lower keyboard of a pair of Roland synthesisers. The astonishingly pure sound of a boys' choir rises into the air, falls. He plays the arpeggio again, with more force. This time it's a trumpet-call, clarion-clear. Magic - or mathematics? A bit of both, says Edwards. "The computer doesn't distinguish between sounds, it simply takes snapshots of them - so it's immaterial whether it's a cor anglais or a choir, as far as the technology is concerned. To make it expressive, that's the difficult part." In other words, to build in the curves, valleys and subtle phrase-endings which come as second nature to musicians in the real world. But with all that technology available, isn't it tempting to go overboard, experiment with all sorts of weird and wacky soundeffects? Edwards smiles. "Hmm. I've been through that phase," he says. Stephen Edwards has, in truth, been through a number of phases in a composing career which began when, as a 19-yearold schoolboy, he wrote an opera. "I was in rock bands at the time, but I'd started to listen to orchestral music. We had one of those mad music teachers who put on productions every 10 weeks; we did everything from West Side Story to Dido and Aeneas, My Fair Lady, Benjamin Britten's The Flood. He approached me to do a rock opera of this piece that he'd written, and when I saw it, I said, `I'll do it - but for an orchestra'."

The experience convinced him to sign up for a traditional music college, and a scholarship to the Guildhall to study composition was swiftly followed by an Australian fellowship to work with a theatre company in Sydney. "When I came back, I was invited to work as assistant to Harrison Birtwistle at the National Theatre; then when Peter Hall left to set up his own commercial West End company, he invited me to join him, seeing how far you could push music into plays. Because of his interest in directing opera and so on, he basically gave me an open brief. I remember calling him and saying, `I want to do Hamlet', and he said, `I've no idea how you're going to get music into Hamlet - but go ahead'."

Edwards has had compositions performed by the BBC Symphony Orchestra and at Sadler's Wells, but since he came to Ireland last July to help set up the Pavilion Theatre, theatre music has absorbed much of his time and energy - and his enthusiasm, as he bounds around the auditorium pointing out its salient features, is palpable. But sound technology in the theatre is a double-edged sword, he says, to be used with caution. "The great thing about surround sound is that with 30 speakers dotted around the auditorium you can either diffuse an effect - wind, say, or rain, or thunder - throughout the theatre, or you can pinpoint it to a particular part of the set. So when we want the church bell to toll, for instance, it will sound as if it's coming from the church. That sounds very cinematic, but this isn't cinema. "You have to do things large in the theatre - small gestures get swallowed up. And the main difference between film and theatre, of course, is that we have to do it live."

When writing the score for a play, he first visualises the scene in his head, then composes the music right through. "Then it's cut into two-bar chunks so that the pianist, in this case Andrew Synnott, can wait for a word cue at the appropriate moment - otherwise things would get badly out of synch. This way it's a case of, `rubato the Bard to make him fit'. And the performers are doing a kind of duet. They have no option but to interact with the music - either go with it, or go deliberately against it to create tension."

There are, of course, tensions a-plenty in Romeo and Juliet, and the Pavilion production's emphasis on the physical aspects of the show can be gauged from the fact that it will employ not just a fight director, Seamus Allen, but a movement director, Caimin Collins, as well. The play is also to be relocated to Dublin during the War of Independence. Does this mean the score will have an "Irish" feel? "I kind of Irish-ed out when we did The Quest of the Good People at Christmas, which intentionally had a Celtic quality about it," says Edwards. "But here we're trying to evoke a period by, say, the use of the piano - and also the kind of soft-edged turn-of-the-century dissonance that you associate with Debussy or Erik Satie." Soundtrack work hasn't weaned Edwards from conventional composition; on the contrary, he says, he still enjoys the very different discipline of writing for acoustic instruments. "When you're writing for large ensembles the music has to get simpler; if only for the simple fact that everyone's trying to go `donk' at the same time, so the music has to be simpler or else it just sounds like a horrible mess. When you're writing for, say, a string quartet, the music can be quite filigree in comparison to Sibelius or something, which is just a series of transformations of a thematic idea." His favourite composer is Bach. "Although the depressing thing about Bach is that even on his bad days - even when you know he's 'phoning it in - he's better than your best effort."

An associate director of the Pavilion Theatre, Edwards sees music as integral to the theatre's developing artistic policy. Plans are already under way for an ambitious new piece for the Dublin Theatre Festival in the autumn, to combine opera, ballet and spoken theatre, while the acquisition of a spanking new three-quarter-size Steinway - "I picked it, and it's a good one" - clears the way not just for classical recitals and chamber concerts, but also for copious quantities of jazz. He'd love to put on Bartok's glorious operatic two-hander, Bluebeard's Castle. "And we're hoping to have a world music festival in the summer. Music has this horrible habit of being boxed up into little holes - and theatre's even worse - but many of our in-house productions will have a very strong music and movement component.

"We want to take theatre in a broader sense, shift the emphasis from the word. We want to attract dance companies, and people who are using all kinds of media. Because I think as audiences, that's what we want - don't we?"

Romeo and Juliet, directed by Karen Hebden, opens at the Pavilion Theatre in Dun Laoghaire tomorrow night. For bookings, telephone 01-2312929