With the arrival of real-time 3-D digital audio processing, techniques for acoustic space modeling and sound source spatialization have become of great interest for implementation in various multimedia applications, ranging from CD-ROM authoring to video conferencing. In surround sound applications, where sound source localization is a primary objective, various digital signal processing (DSP) techniques can be employed to heighten the sense of source localization, often creating a stronger link between sound and image. In several multimedia applications, the degree of live interactivity can play a crucial role in the success of the application. For example, the underlying software in video games, acoustic space simulators, and air traffic monitoring systems (using auditory display) must render audio objects in a real-time acoustically modeled space, based on varying position data supplied to these programs by the user(s). This paper will focus on sound source localization techniques and their use in various multimedia applications, and will examine key issues in implementation.