I am using one of my PCs as Home Theater PC. It's an Asus A7V8X-X mobo with an on-board sound chip Analog Device's AD1980. It's got SPDIF out as well. I am feeding that output via coax cable to my Denon AV-Receiver. All was working fine, I could playback Dolby Digital or DTS on my puter and the sound signal was being detected by my AV-Receiver correctly. Last month I lost all sorts of surround sound out of my computer. That is, the AV-Receiver was detecting neither Dolby Digital nor DTS. The coax out was half-working, meaning, the sound signal was transmitted, but just as PCM and that without surrounds, even though I was playing Dolby Digital or DTS. I ran SoundMAX's loop test only to find out that no test music was being played on my surround speakers. I formatted the hard drive and made a clean XP installation + the sound drivers that came with the mobo. Then I immediately ran the test. Still no surround test tone out! So it can't be sound drivers that've gone bad or been replaced. I checked the coax input of my AV-Receiver using the coax out of my DVD player, it worked fine. So it can't be the AV-Receiver, either. The only remaining option is that the chip itself went bad!! This is so unusual for me. I've plugging this and that card into various computers and I haven't come across one bad chip yet. That's why I find it so hard to believe. What's your take with on-board sound chips? Have you ever heard of one that went bad? Is is possible at all? Please help me understand what's going on.
My ASUS motherboard's sound chip (also an Analog Device) didn't do a very good job with SPDIF passthru - no signal at all from the getgo. Good thing I had an old CL SB Audigy2 that was laying around. Now DD and DTS get through to my Marantz without a glitch. It could very well be your on-board chip that's giving you the problem. You've done pretty much everything to troubleshoot. Do you have an unused PCI slot for a soundcard?
Hi dblbogey7, Thank you for your reply. Yes, I have several empty PCI slots. It looks like I need to shop for a new sound card. What would be my cheapest but most guaranteed solution? I mean, which brand amd model? It can even be an external box that connects over USB 2.0.
If all you want is SPDIF pass-thru you don't really need a very expensive card. I have an old Soundblaster Audigy2 which works just fine. I've read good things about this insanely cheap Chaintech: http://www.newegg.com/Product/Product.asp?Item=N82E16829120103 More expensive but with really good reviews are the M-Audio cards: http://www.newegg.com/Product/Product.asp?Item=N82E16829121122 Good luck.
Feedback: Yup, it turns out the on-board sound circuitry really went bad. I bought a new soundcard (PSC724) with SPDIF pass-thru and now both AC3 and DTS streams get detected correctly.
