This example attempts to approximate the real life transmission of soundwaves through air using a waterfall in a large valley during one of the opening levels of Conan for X360/PS3.
One loop was positioned at the waterfall with a shallow LPF that gradually (over the course of 100 meters) released the high frequencies tied to a distance parameter from the game. I then placed 2 additional waterfall sources under the bridge with smaller rolloffs and a tad steeper LPF, they add diversity to the "global" one and the textures/ frequencies of the 3 sound massive as you battle your way across.
Additionally the 3d Pan and 3d Speaker spread are being modified based on distance to help keep the emitters from sounding too positional when the player is far away.
Bay Area Sound Department