Brothers Ryan and Hays Holladay, better known at the experimental duo Bluebrain, have staged a Cherry Blossom boom box walk, performed with giant Seussian backpacks strapped to their bodies, and have even done a 3-D show. Their latest project is a "location-specific" album, The National Mall, meant to be listened to while exploring the giant national park.

Bluebrain gave a explanation of the science behind the album, which will be available as an iPhone app, on its blog yesterday.

The National Mall works by tracking a user's location via the iPhones built-in GPS capabilities. Hundreds of zones within the Mall are tagged and alter the sound based on where the listener is located in proximity to them. Zones overlap and interact in dynamic ways that, while far from random, will yield a unique experience with each listen. The proprietary design that is the engine behind the app will stay hidden from view as the melodies, rhythms, instrumentation and pace of the music vary based on the listeners’ chosen path. The National Mall is an ambitious project that will allow users to listen to and interact with a work of music in a way that’s never been possible before.

While this is the group's first album-length site-specific work, they've composed music for locations before—last year they put together a musical tour of Sant Ocean Hall at the Natural History Museum.

They added that the app is "not a toy or game" that can be customized or tinkered with by the user, and that "[e]ach position on the map has been carefully considered, the music composed and recorded to be heard in their specific place in the same way you would hear a piece of music on a physical record. However, because each listener will explore the Mall in a different way and at a different pace, experiences with the album will be unique in sequencing and in arrangement."

The album will be available in the iPhone app store in the coming weeks. The brothers also said that The National Mall will be the first in a series of location-specific albums, and that a project made for Brooklyn's Prospect Park and the entire length of California's Highway 1 are in the works.