Hi, I have just worked on an APO in Windows Vista. And now I am missing them in windows XP. After reading some threads of the WDMAUDIODEV list, it seems that there are no easy way to do it in Windows XP. I would like to know what are the different way to process audio data in windows XP? Do you think that it is possible to apply global audio effect in "User-Mode"? It seems that SRS Audio Sandbox succeeded to do so. Thank you M'hand Boughias