Hey guys, Need some help with a problem I am having. Currently running on a built computer with an ATI 4670 and an Audigy 4 Pro (I know creative but i had it from an older computer) I am not outputting sound via the motherboard or the hdmi out. I am using the optical out from the creative sound card. I have to use this because of the mixer i have attached to the card for a couple of mics i have attached (karaoke). Anyway. When I play a .avi file with AC3 audio stream. I would get this chopping noise (via Windows media player). Like a helicopter with its blades. This does not happen in VLC or GOM. Another thing to note is that when trying to adjust the volume via windows (speaker icon or volume control in WMP), the sound persists. the volume only changes by adjusting it on the receiver (Denon 3808ci). I know it was probably a filter problem. I have no other codecs installed expect for mkv playback via GOM. So i decided to install the AC3 Filter. This immediately fixed my problems with the .avi files. But playing dvds through windows media player the problem persists!!! a few things to note. idk how to get spdif passthrough to work. because for the audigy properties i can either choose: Use external Decoder (SPDIF passthrough) Use internal Decoder selecting either of these, the sound problem is the same. there is also an spdif i/o tab Default SPDIF in-decode SPDIF bypass (red light turns off if i pick this) And to top it off I dont know what to pick in the AC3 filter configuration. If "Use SPDIF' is UNCHECKED, then sound will work normal in .avi but not in dvds. If i CHECK "USE SPDIF" then no sound at all comes from the .avi or the dvd (not even the chopping nosie) i am trying to be as explicit as possible with my problem. Running Windows 7 x64. Sound file attached (helicopter noise!!) Download Audio Static.mp3, upload your files and earn money. I know someone has to know about this stuff. Please help!!!! thanks!!! PS: IN total media theater 3, the dvd files work fine (dont know about spdif passthrough but at least they play!!), but my dad wants to use WMP!!! i dont know why, but i think it has to do with the fact that he wants to use windows media center. i havent tested this in windows media center. i would imagine it uses the same stuff that WMP uses... also i read somewhere replacing msmpeg2adec.dll with the one from vista sometimes cures the problem, tried it. no avail. its a long post thanks for looking.