Wide spreading of digital data over the Internet has lead to the increasing need of finding a way to protect their copyright. For that reason protections like digital watermarking have become an interesting area for investigations and scientific researches. In this paper a brief description of the digital watermarking technique is made. A comparison between steganography and compression is also discussed. The authors have gone through the basic elements, needed for the construction of a system for embedding and extraction of digital watermarks.

The Wave Field Synthesis (WES) concepts have steadily gained popularity over the past decade. It is based on physical sound field rendering within a certain listening area. The pure audio signal is combined with informations about the room and the source's position to enable the accurate reproduction of the source within its acoustical environment. This is made by precise construction of the desired wave field by secondary sources; implemented as arrays of loudspeakers. The method is implemented in a practical approach based on physical as well as perceptual laws. Sound rendering requires that many different aspects are considered, especially when rendering a real-time virtual environment.