Apple's 'directional audio' concept is like multitouch for the ears

Apple has worked on "directional audio" technology, specifically employed as an audio user interface, allowing users to make selections and navigate menus based on audio cues in a three-dimensional surround sound environment.

The concept was revealed this week in a new patent application made public by the U.S. Patent and Trademark Office named "Directional Audio Interface for Portable Media Device." Discovered by AppleInsider, the filing shows Apple's interest in creating advanced portable devices and accompanying headphones to augment the user interface of the device.

The concept includes one or more "audible control nodes," which are perceived by the user through sound to be located at different points around them. Like the multitouch interface Apple popularized with the iPhone, it's a new twist on an existing way to interact with a portable device, far more advanced than the Voice Over controls featured on the iPod touch.

Apple's application notes that in some contexts, such as driving or running, a user may need to interact with their device in a non-visual manner. While simple actions such as pressing an on/off switch or skipping to the next track may be relatively simple, more complex actions like searching for a particular media file are too difficult to accomplish without visual feedback.

The solution proposed by Apple is an "alternative user interface" that could supplement a device like an iPhone or iPod, allowing users the ability to interact with and control without seeing. This would be accomplished in part through audible cues to the user delivered in a three-dimensional space.

When an option is presented to a user, it could be selected by physically moving the portable device in the direction of the "audible control node." In essence, a user would hear a sound from a particular location via their headphones, and would point a motion-detecting device like an iPhone in that direction to select it.

The application notes that with binaural output to a user through a stereo headset, a portable device can reproduce "spatially distinct" sounds. Coupled with a motion sensor in the device, this audio-based user interface would supplement or perhaps even replace a visual user interface.

Menu items could be presented in a variety of forms, including synthesized text-to-speech, recorded speech, or samples of recorded music. Audio cues could also be played back sequentially or all at once.

Apple's patent application, made public this week, was first filed in December of 2009. It is credited to Aram Lindahl and Richard Powell.