A new 3D Audio Playback Engine (3DApe) and an associated 3D Audio Soundtrack Producer (3DASP) were developed for a distributed and interactive, spherically-panoramic 3D cinematic artwork, Conversations, which was exhibited at the Powerhouse Museum in Sydney, Australia (December, 2004). 3DASP is designed to produce spatial-audio soundtracks with no restrictions on the number of sound sources that can be rendered simultaneously with real-time head-tracking in virtual auditory space. 3DApe is an auditory user interface (AUI) which can simultaneously play back pre-rendered, spatial-audio soundtracks created by 3DASP, spatially render up to four instantaneous and simultaneous sound sources on command and provide 3D audio communications using voice over IP. 3DApe provides complete control of its functionality via command messages passed using socket communications. In the Conversations exhibit, 3DApe was controlled by the Virtools graphical software engine.