A speech communication environment using open source software library for active sound image control

Abstract

This paper describes a three-dimensional (3-D) conference system using an open source software library on conventional PCs. We will attempt to use both 3-D graphics and audio to construct a virtual conference environment for effective communication between remote parties. A rough prototype system was developed using OpenGL and OpenAL. The system uses local files for voice output, whose image location is rendered according to the user input. We initially evaluated the perceived sound image location accuracy of the rendered sound image using the prototype. Users were asked to identify the location of the rendered sound image from among four choices: front, back, left, and right. The users were able to identify the left and right images correctly at virtually 100%, but the front and back identification were lower than 10% for some sounds, particularly male speech. We plan to implement audio-streaming functions to achieve real-time audio conferencing and evaluate the benefits of 3-D audio for conferences. We would also like to implement HRTF (head-related transfer function) and RTF (room transfer function) for improved audio image localization, especially to achieve accurate elevation perception.