Universe of Sound installation premières at the Science Museum Upstairs at the Science Museum, past Foucault's Pendulum and all that fascinating early industrial machinery, something very unusual is going on. You hear it before you see it, as the sounds of Holst's The Planets filters down the corridor. Eventually you find the source, a new interactive installation entitled "Universe of Sound." It's built on the model of those art installations where you walk through a portico, like the entrance to some mythological underworld, and enter a darkened space with lots of interconnecting spaces. On the walls there are close-up images of the musicians playing Holst's stirring music: a group of string players in the first room, oboes and clarinets in the second, brass in the third, and so on. The idea is to draw people into the "universe of sound" that is the orchestra. It follows on from the Philharmonia Orchestra's first digital installation "Re-Rite" almost three years ago, which was focused on the Rite of Spring. So, why Holst for the second? "We wanted a big iconic piece of British orchestral music, as this is part of London 2012," says the Philharmonia's principal conductor Esa-Pekka Salonen, "And also this piece is the perfect entry-level piece. It's so familiar, it's been used in so many different contexts. People will know it even if they think they don't know it. And that makes it easier to draw them in to the detail of how an orchestra actually works, which for most people is a complete mystery. It looks so formal and ceremonial at a distance, and this will remind people it's all about real physical work. Like "Re-Rite," this installation adjusts the sound-mix in each room, so that, for example, the percussion sound is more prominent when the percussionists spring into life. In the middle is a central dome, where we finally get to see the hidden hand that's controlling all this, i.e. Salonen himself. He appears in the middle of a 360 degree image of the entire orchestra. Technically it's an impressive feat, and as Salonen points out is more advanced than Re-Rite. "The images are all shot in HD, and we've used movement detection software to set up these little virtual conductors" booths, where people can try out their conducting skills." A wide screen gives a conductor's eye-view of the orchestra, and there's the option to "conduct" at different levels of difficulty. If you go wrong, the sound goes wrong too, and there's a sudden barrage of coughing (perhaps a slow hand-clap was judged to be just too cruel). There's another extra element, in the form of a new final movement commissioned from composer Joby Talbot. "What Esa-Pekka wanted was a piece which involved an interactive, compositional element for the viewer," says Talbit, "So I've written a piece where at certain moments the viewer can choose between scorings for the piece. For example you can switch the melody from horn to cello, by dragging an icon across the screen. I had to make sure the music worked as a piece, so I've kept control of the overall shape. Which is? Well, it begins with the mysterious oscillating chords at the end of Holst's Planets, and builds on that, up to a really big apocalyptic climax. It's a journey outwards which changes as we pass by another sun or star, and eventually builds to a big climax and then dies away again to nothing. For newcomers to the orchestra, this installation certainly gives a taste of its amazing richness. But it could be useful to music-students too, keen to get some tips on how to balance winds against brass. Salonen himself has learned things. I have to say when I walk through this installation, I'm seeing people I work with and know very well, and yet I'm experiencing things in the score I haven't noticed before. Part of the fun is waiting in a room where nothing much is going on, and looking for the signs that tell you something is about to happen, like a flexing of a hand or a discreet blow down a clarinet to warm the tube. As you wander about, you get an impression of the orchestra as a magnificent piece of well-oiled machinery, its parts all ready and waiting. The technology may be new, but it's really an old-fashioned "Universe of Sound" we're offered here. Everything fits beautifully like hand and glove, the sounds are so rich and sonorous, there are no loose ends or accidents. You could almost imagine it was created by the Almighty. The Philharmonia Orchestra's Universe of Sound is at the Science Museum London SW7 23 May - 8 July