i just hooked up a 4 speakers setup to my santa cruz but need some way of verifying that 3d sound works. I tried to test it with half life in a3d mode but I couldn't tell whether sound came from the back or front. Maybe my configuration is wrong or the 3d sound is not very convincing with the santa cruz which I doubt. Anyways a 3d sound test software can easily help me diagnose the problem. Anybody know of any I can download for free off the net?