May 1, 2011
Most of us have 2 ears. None of us have 5.1 ears. So why do we need complicated expensive equipment to render 2 dimensional sound? Current 5.1 sound solutions deliver directional sounds on a flat 2 dimensional plane. These systems enable us to identify the location from which sound is emanating on a 360 degree axis. In other words with current surround sound we can identify that a sound emanates from behind us and to the right. Yet even with $50K plus top-of-the-line 5.1 or 7.1 or 9.1 equipment the surround decoders are unable to render the height of that sound. It is impossible to determine if sound we heard behind us and to the right emanated from the ceiling or the floor. Surround sound is height agnostic.
Why can’t all this equipment duplicate the 3D listening ability of our 2 ears? How do our ears achieve the capability that all the best audio systems fail to deliver?
The human brain possesses processing capabilities unequaled by today’s best audio equipment. The secret to rendering realistic 3D sound involves understanding Head Related Transfer Function (HRTF). Simply stated HRTF is the process of coordinating the inputs to the brain, inner ear and external ears and then computing those inputs to infer the originating locations of sound. Sound waves bounce off of walls, floors, ceilings and our shoulders before they are received by ears multiple times with subtle, barely detectable time differences. A single sound bouncing around the environment is detected by our ears multiple times. Our brain processes these time differences to determine the location of the source.
Today, a University of Maryland developed technology being commercialized by VisiSonics, located in College Park, MD, is taking audio to the next level. VisiSonics’ algorithms reproduce real-life nuanced sound differences in any standard off-the-shelf headphone, fooling the brain into believing that the sounds emanated from any desired location. VisiSonics can simulate surround sound from any 5.1 source like video games, music or films and render it to be heard on standard headphones. In the future, games developed using VisiSonics software will be able to duplicate real life sound that exceeds the capability of surround sound. VisiSonics demonstrated to me the ability to simulate the sound of a helicopter flying completely around my head. Hovering under my chin, behind my head and above me.
In the future, 3D games developed with VisiSonics sound software will allow gamers to enter fully rendered 3D worlds, 3D movies will be enhanced with sound that matches the video realism, and Live From The Met opera broadcasts will sound to a remote viewer as if they were sitting in the best seat in the house.
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