Sound in the round

A helicopter roars overhead as the sound of sirens appears in the distance, the cars drawing gradually closer before circling the building. You start to hear rain hitting the roof above you and trickling slowly to the ground. Then an almighty explosion engulfs the theatre, passing from front to back as bullets fly past your seat. Luckily, none of this is real. These are the sounds of the next generation in immersive entertainment to hit cinemas: 3D audio.

We’ve already become used to watching images pop out of the screen or disappear into the distance when we’re enjoying the latest blockbuster movie with 3D visuals. But most people have yet to experience 3D sound, even though it was invented decades ago ­– a fact that could be about to change. In some forms, it’s an evolution of the surround sound we’re used to encountering in cinemas or home entertainment systems. However, the concept of 3D audio isn’t necessarily about placing more speakers around an audience; it’s about recreating sounds in a way that tricks listeners’ brains into thinking they are hearing them live rather than as a recording.