I'm trying to set up an HTPC driving a Panny AE300 and Marantz SR4300. I'm using PowerDVD 5 (all I got at present), the PC has an Audigy Platinum Ex card, using an OPTICAL SPD/IF connection to the amp. My problem is I can't get anything other than STEREO out. PowerDVD is showing "Dolby Digital" as the 'current audio coding' and SPD/IF as the 'current audio mode' .. the SR4300 though is showing PCM as the input whereas when I select my DVD player as input unsurprisingly the SR4300 shows "DD Digital". For the life of me I can't see what I can fiddle with to persuade the software player to output a DD stream ... I'd have thought selecting SPD/IF was sufficient for it to simply chuck out the encoded AC3 stream to the digital output and thus the amp should see it as such. Can anyone suggest what I've missed setting this up? Again unsurprisingly if I use the analog 6.1 outputs from the soundcard to the 6.1 inputs on the amp and let PowerDVD decode it then all's as expected. Cheers. EDIT: Typical .. I spend an hour fiddling, post this, then 30 seconds later discover my problem ... yet another config dialog in the Creative Mixer. Now got loverly 5.1 sound and great picture. Sorry to have troubled you.