Enter the maze

Silent drum


We know the music world can be pretty crazy sometimes, but would you think it's a world where drums are silent and shadows make sounds? It is now.

Inventors are continuously coming up with new technology that enhances the musical experience of performers and composers. 2009 was no different, as shown by the Guthman Musical Instrument Competition at Georgia Tech. It showcases new musical instruments whether played by human, computer or robot. The competition scoring is based not just on musicality but also on design and engineering. Nearly 30 inventors from seven countries battled for $15,000 in prizes with Jaime Oliver (a Peruvian computer scientist, not the TV chef), the ultimate winner for his Silent Drum.

Jaime is a PhD student at the University of California, San Diego, where he is researching the use of gestures to control electronic sound. He developed the Silent Drum with Matthew Jenkins. The original idea was that it would be hit by a mallet. As they experimented with it, though, they realised that you could get much more subtle control of the sounds if they used hand gestures instead.

Physically the Silent Drum is just a drum shell with an elastic spandex head, lit from the inside. It's electronic, so it doesn't need physical motion to create a sound. Instead it uses shapes and shadows to compute and control the sound it makes.

When you press the drum surface, either with a mallet or your hand, you can create all sorts of different shapes. They are captured by a computer vision system. It analyses the images from a video camera that is part of the drum and translates different shapes into different sounds. That means the drum really is silent. It is the computer that generates the sounds based on what it 'sees'. The sound depends on things like the position of the player's hand, the shapes it makes, changes in direction of the hand and so on. Each such 'parameter' can be used to control the sound in different ways.

Essentially what the silent drum does is turn shadow puppetry into a musical art form instead of a visual one.

Shadows never need to skulk around silently again!