Thursday, February 26, 2009

Emoti-chair allows for music to be heard with the body, concert for deaf community scheduled

From the National Post in Canada:

In a small Toronto tavern next week, people who cannot hear will crowd into the room to experience music.

The unusual concert, in what organizers say is the first ever concert for the deaf, is a rather public experiment by those who specialize in the science of music, who will use computers to translate audio signals into tactile sensations, along with visual projections that mimic the tempo of the music.

The science is said to help deaf people experience music so vividly that some can distinguish between genres of music or even individual instruments.

"I can tell the difference between jazz and classical music," said Ellen Hibbard, a deaf individual and a PhD student in Communications and Culture at Ryerson. "I've started to like blues for when I want something more mellow than jazz.... I now can recognize if there are vocals in the music."

What allows her to experience music is a unique development invented by a team of researchers from Ryerson University's Centre for Learning Technologies and the Science of Music, Auditory Research and Technology (SMART) Lab.

Deaf people who listen to music using the lab's Emoti-Chair will often experience a physiological response similar to those who can hear it, said Dr. Frank Russo, director of the SMART lab and co-inventor.

The chair is equipped with 16 vibrating motors known as voice coils, spread across the body of the chair. Music is inputted into the chair and undergoes what is known as a Fourier transformation, where the sound is broken down according to its different frequencies. Those frequencies are then channelled to the voice coils to be picked up by the user's back. Higher frequencies activate voice coils at the top of the chair, and lower frequencies activate coils at the bottom end of the chair.

"Basically what we're doing is we're treating the back as the basilar membrane of the inner ear," said Dr. Russo, who has been studying the effect of music on humans for 15 years. "We're taking the output from that Fourier transformation and displaying it across the back."

He said the technology is designed to be a metaphor for turning the human body into a cochlea, the main organ responsible for hearing, replicating its ability to separate music into multiple, discrete packets of audio signals presented to the body as vibrations.

Deaf people already know that the appeal of music goes beyond the auditory, Dr. Russo said, as they will often go to clubs and place their bodies against a speaker box to indulge in a vibratory experience of what they cannot hear. But with that form of speaker listening, the true nature of the music is often obscured as lower frequencies tend to drown out higher ones, he said.

In order to tell the difference between the sound of one instrument and another, you need to have a sense of the full spectrum, not just the low end. The technology behind the Emoti-Chair allows users to experience a reproduction of all the frequencies, so that their bodies can actually feel the highs and the lows.

Dr. Robert Zatorre, a professor of neuroscience at the Montreal Neurological Hospital and Institute, said although about 99% of a hearing person's appreciation of music stems from the audio input, the brains of deaf people will rewire over time to enable them to decipher audio cues through their other senses.

When a deaf person receives vibratory input from the skin, it gets converted into something akin to sound, he said.

Brain-imaging techniques show that when a hearing person experiences a vibration on their fingertips, the part of their brain related to the fingers will light up, he said. If that same stimulus is applied to a deaf person, however, the part of their brain that normally responds to sound lights up, although Dr. Zatorre is hesitant to equate that sensation with hearing, because the inner membrane of the ear is vastly more sensitive than skin.

Still, he said the potential for the brain to improve and reorganize its method of sensory perception is vast.

The concert, which is to be held on March 5 at Clinton's Tavern, will rely on the combined effect of seeing performers on stage, along with the detailed vibration of the Emoti-Chairs and a series of visual projections to allow local bandssuch as the Fox Jaws, Hollywood Swank, and Treestar to perform.

Those who can hear, however, may find the concert exceptionally loud as it caters to those with limited hearing. Free earplugs are to be handed out at the door.