Syren, a location-based, multi-speaker augmented audio reality installation was presented as a shipboard exhibit at the 12th International Symposium on Electronic Art in August 2004. It was conceived as a continuous 3-day spatial audio experience that augments the landscape through the Baltic archipelago with location-based audio media, spatialised through a 12- channel speaker array. As the ship tracks between Helsinki, Mariehamn, Stockholm and Tallinn, listeners on the upper deck hear sounds that are perceived to originate from geographic features. Our custom GIS is derived from electronic nautical charting information that includes coastlines, buoys and beacons. A handheld GPS provides both position and direction data that was used by a software system to drive parameters of the spatial audio presentation. The sound production for the artwork was created using the custom application that enabled the artist to place sound media in relation to a real-world map. An important component to this software was the ability to audition the audio experience without ever taking the journey.