Music by numbers

At worst it's a "karaoke machine," at best it's "progress", according to fans of the musical Les Misérables on a busy web forum about the new virtual orchestra being used at London's Queen's Theatre.

At worst it's a "karaoke machine," at best it's "progress", according to fans of the musical Les Misérables on a busy web forum about the new virtual orchestra being used at London's Queen's Theatre.

When the show moved last month to its new smaller home, it lost half its musicians due to limited space. To preserve the audio drama of the Palace show, the promoter Cameron Mackintosh chose to be the first in the UK to use a technology called Sinfonia to boost the relatively thinner sound. Though the fans may feel somewhat cheated by having some of the live essence of the show stolen by this unknown technology, Sinfonia is no karaoke machine; it is alarmingly good at simulating live orchestra musicians. And not surprisingly, those musicians are worried about their futures.

What may be surprising is that Sinfonia is designed and built by people who say that they "really know music and what is important to musicians", the American company RealTime Music Solutions. The process begins with much better quality samples than we are used to in synthesised sound. To that, add filtering software, allowing up to 50 different sound nuances, to better simulate the quality of a live instrument. The software can layer these instruments together to build a virtual model of the full score. (This kind of sound processing requires substantial computer power, as well as stacks of memory.) The instruments being played live are then muted from Sinfonia's real-time delivery. During showtime (and this is the cleverest part) the person playing the Sinfonia keeps time with the conductor's baton; but not simply by tapping a key.

"He or she plays a fully notated musical phrase, following a score as well as the conductor and stage action," explains Jeff Lazarus, the chief executive of RealTime. "Other performance features include ways to initiate arbitrary vamps [improvisations] and relocates [key changes], holds and cut-offs for big fermatas [extended notes], pick-up phrases [opening lyrics], and more." This allows the "sinfonist" to stay in sync with the actors on stage, despite common events such as late entrances, where the musical cue might need to be repeated, or varying lengths of pauses before the music comes back in.

This ability to play along with the conductor is the ground-breaking differentiator of this technology: without it, orchestras must often rely on playing along with universally loathed "click tracks" or pre-recorded snippets. The ability to add nuance to the high-quality samples is also key as, Lazarus states: "It is not uncommon to see three or four synthesisers in a musical theatre orchestra pit. The synthesisers are almost always being used to approximate a larger traditional orchestra - more strings, or all the strings, more reeds, and so on." RealTime's vision for Sinfonia was to combine all the electronics into one space in the pit. "Overall, this improves the sound - as well as creating more work for acoustic musicians. And it frees up chairs for a violin, an oboe and so on."

Except that those chairs were already occupied. Sinfonia is so good at its job that it is making the musicians' unions on both sides of the Atlantic increasingly nervous. Its arrival in the US last year caused strikes that closed Broadway theatres. In the UK, Mackintosh was spared that controversy because The Queen's Theatre pit is simply too small for the full orchestra of the Palace Theatre, from which it transferred. Nine musicians lost their jobs. (Arguably, though, they would have lost them anyway in the move.)

But the topic is still controversial. When asked for a comment, the theatre's press office replied the show had signed an agreement not to talk about Sinfonia.

Horace Trubridge, the Assistant General Secretary of the Musicians' Union, says they are still in talks with the Society of London Theatre about the regulation of this device. "So long as it fits the genre, then it's fine," he says. "If you're putting on a show about Kraftwerk you wouldn't expect to see a bunch of musicians in the pit. But if it's Oklahoma!, an audience would expect a traditional orchestra. We object to its indiscriminate use where musicians could otherwise reasonably expect to be employed."

Musicians themselves are ambivalent. Michelle Wright, a freelance violinist says: "This technology has to be better. It's really an insult if you're losing musicians to a string section played on a synthesiser." But on the other hand, she also finds the idea of it "belittling". "Musicians must be protected," she says, "as it demands such a high level of training and there are so few jobs as it is."

Lazarus insists that Sinfonia has never cost musicians jobs. "It has always been used to enable productions to sound better," he says, "always with the same number of musicians planned before Sinfonia entered the picture; frequently with a greater number." There's no doubt, though, that this technology has the power to change the contexts where we are used to hearing the big orchestra sound.

If the technology were readily available, its impact could be far reaching. Besides musicals, any musical performance that tours the UK, and even pantomime, might find it attractive. "There may also be a danger of ballet companies being tempted to use it," says Bill Kerr, the Orchestral Organiser of the Musicians' Union. It has been used to compose film scores, and new enhancements in the pipeline will include improvisational features for use in live jazz combos.

In the US, last year's strikes might soon have an off-Broadway echo. The Opera Company of Brooklyn (OCB) has just decided to throw out the agreement it signed in February with the local chapter of the musicians' union, which restricted its use of Sinfonia. In retaliation, the union filed a federal unfair labour practice complaint against OCB for voiding the pact. The OCB sees Sinfonia as central to their future strategy because it "allows a small company like us to present these great operas", insisted the board in a recent press release. Their view is that this technology will help them to put on more productions that will, in turn, employ more musicians.

But what of losing the live essence? Some fans may feel as if big business is trying to pull the wool over their eyes, thinking that the audience is too unsophisticated to notice, or care. Whether they will care as the use of Sinfonia, or similar devices, becomes widespread is another question. In the context of a big-budget musical with fantastic sets, special effects and highly amplified sound, just how important will it continue to be to have a full complement of live musicians in the pit?

"I don't think we're going to wake up to theatres filled with these devices," says Trubridge. "Andrew Lloyd Webber's new show The Woman in White is in rehearsals with orthodox instrumentalists and he is raving about the sound." Buoyed by the uptake in interest in live music over the past year, Trubridge remains philosophical: "I could see a time when, say, if things got really terrible with many musicians being replaced with technology that someone would say, 'Hey, why don't we have a live band?' and that would become trendy again. It's about peaks and troughs, and I just cannot see the complete removal of the band."