> ### Silent sounds hit emotional chords

> Tim Radford, science editor
> Monday September 8, 2003
> The Guardian

> Scientists have found a way to add a spine-tingling dimension to modern music. They played an experimental organ pipe too low to be heard and then collected reports of strange reactions - sorrow, coldness, anxiety and shivers down the spine.

> They were playing with infrasound, the point at which an instrument resonates at an inaudible frequency. The experiment was conducted during concerts of contemporary music at the Purcell Room in central London.

> "Infrasound has been suggested as weaponry because it has potentially negative effects on people as it vibrates the. Some people have suggested the presence of infrasound is causing unusual experiences in sites that are allegedly haunted," said Richard Wiseman, a psychologist at University of Hertfordshire, who will outline the research at the British Association festival.

> "Some organ pipes in churches and cathedrals produce infrasound and this could lead to people having very weird experiences within church and attributing it to God. We wanted to try to assess some of these claims."

> The guinea pigs were 750 concertgoers who turned up to listen to music by Philip Glass, Pärt, Debussy and more recent composers - including Sarah Angliss, who joined the scientists in devising the experiment. Humans hear at a range of frequencies from 20kilohertz down to 20hertz - lower than a bat's squeak, higher than a whale's rumble. But some organ pipes produce frequencies as low as 16.4 herz.

> To test the theory that infrasound could trigger sensations, the researchers worked with physicists to add silent notes to parts of the music. They also handed questionnaires to the concertgoers to see if any unusual sensations coincided with inaudible bass lines.

> One of the ghost instrumentalists monitoring the bad vibes was Richard Lord of the National Physical Laboratory. "It was a double blind experiment. I didn't even know, before the concert, which pieces the infrasound was going to be in."

> The audience reported 22% more "unusual experiences" during those pieces accompanied by infrasound. They reported "shivering on my wrist, an odd feeling in the stomach, increased heart rate, feeling very anxious, a sudden memory of an emotional loss," said Prof Wiseman.

> Natural sources of infrasound - wind, air conditioning systems and traffic for example - could possibly explain why there were persistent reports of hauntings in some buildings. But the environment would affect the attribution, he said.

> "If you walked into a modern building and suddenly felt sort of ill but didn't know why, it might be sick building syndrome. If you walk into an old Scottish castle with a reputation, that's a ghost."