India, Feb. 23 -- Close your eyes at a live performance and you'll realise there's a secret superhero at work. At music festivals, dance recitals or even when the wedding reception features a band, somewhere, there's a sound engineer who knows that every note matters, and every ear deserves to hear it.

It's a tough job. Sound engineers are the first to arrive and the last to leave. They determine if the bass thump at a rock gig is powerful enough to reverberate through your ripped jeans and your drink. They know when a guitar solo is coming up and needs to be louder and clearer than the rest of the song. They know how to distribute the music evenly across a large venue, so when your jam comes on, you can rush towards the stage even thoug...