Immersive environments for teleconferencing, collaborative shared spaces and entertainment are set to become key elements of future communications systems. Spatial audio is an essential part of this emerging immersive environment technology. This paper describes a number of immersive environments developed at BT Laboratories covering the design and implementation of spatial audio for a range of systems from a single person SmartSpace chair using transaural processing to a multi-user VisionDome using a combination of ambisonics and non-linear panning. It was necessary to take existing spatial audio techniques and adapt them to suit our specific needs.