3D Audio (Spatial Audio) Rendering in a Headphone Environment |
| We have successfully attempted to render a monophonic audio stream into a virtual 3D environment. For the midterm report an extensive literature survey was conducted in order to determine methods which have been used by other research groups to create such effects. Summaries of our findings are available. And the seemingly best approch was implemented. The model based algorithms found were then implemented in software using MATLAB, tested using headphones, and demonstrated. The results for displacing the sound source horizontally worked fairly well, while vertical displacement was difficult and yielded unconvincing results. In addition to what we had planned on doing for the midterm demo, a room (a dome) echo was added to our findings in order to combat the "in head" experience of using headphones. Because the vertical displacement of the sound source was rather poor, another approach to 3D audio rendering was tried. MIT's Media Lab has collected and distributed, head related transfer functions. These were used for our final algorithm developement and they displayed better results than the model based approach especially in the vertical displacement of the sound source. A perceptual test was developed. it compares the horizontal displacement of the sound source of the hrtf and the model based approaches and shows the effectiveness of the hrtf approach in both vertical and horizontal displacement. Data was collected from ten volunteers and the data analyzed. The only commercial algorithm available that we could compare our work to is a new company, Wave Arts founded by the person who inspired much our work, Bill Gardner. It seems he has learned a couple of tricks that he hasn't published, Our work is unfortunately not as good as the effects created by Wave Arts' software tool. In addition to what we had planned on doing for the final demo, the room echo was refined so that the user can determine the size of the room and the sound source location. This model is very effective although it should be noted that it is a model of an empty rectangular room. |
| Link to Project. Link to our code |