I am writing as I believe I have exhausted any possibility of getting a (useful) answer from Asus customer service.
My problem is that I cannot manage to get any digital sound (i.e. other than stereo) out of the coaxial connexion of my ASUS M3N HDMI motherboard. I will probably end up buying a soundcard, but thought I would give it another try.
More precisely: I have built a HTPC – TV (Sony Bravia) is connected to the PC through HDMI, and for sound through coaxial directly to a Sony home cinema (DAV-DZ860). The Home cinema system does not detect any digital sound, i.e. sound comes as stereo only from motherboard, even when reading DVDs. Same happens when I use the RealtekHD Audio Manager - Audio I/O tab > selecting 6ch speaker: when testing sound, only front left and right speakers work (i.e. no sound from rear speakers, from central speaker and subwofer). Can't test HDMI as my TV will convert any digital signal into stereo and my home cinema does not have hdmi in... Also, the SPDIF volume control in the windows sound mixer is greyed out.
I know others have had similar problems, but none of the solutions have worked for me.
What I have done so far: trying reinstalling windows xp / trying uninstalling all drivers (Nvidia and Realtek) and then reinstalling the newest drivers one by one after suppression in registry (like described in this thread http://www.tomshardware.co.uk/forum/page-245488_10_0.ht... / fiddling with
enabling-disabling HDMI audio in Bios.
I have tried both the drivers on the ASUS
Support site and those on the realtek/Nvidia sites / reinstalling Directx / uninstalling Windows UAA (hotfix KB888111 and its updated version by Microsoft – does not work with SP3).
OS: Windows XP Professional (32bit) with all latest updates
M/B: M3N-H HDMI
CPU: AMD Phenom II X2 500 3700 Mhz
RAM: Kingston DDR2 PC8500 2 Gb
No additional PCI card
BIOS: Revision 1902
GEFORCE 8300 driver version 182.50
Realtek HD Audio driver version 188.8.131.5219
If your using HDMI, then sound is covered. HDMI will take care of both sound and video, up to 1080p. My suggestion would be to try DVI and then use the coaxial sound. Using HDMI and coax may not work so well, seeing as HDMI will try to manage sound as well. Good luck.
Thanks for your answer, I actually thought of that and tried to fiddle with the Nvidia HDMI driver options (sorry not at my computer right now so this may not be the exact terms used...) by deactivating sound through HDMI. So I didn't get HDMI sound anymore but still no luck in geting 5.1 through the coaxial. In addition, I do get sound through coaxial, but just stereo...
Just in case someone is facing the same problem, I figured it out: not a motherboard problem, but simply settings in FFDshow audio decoder under Mixer, make sure you have the correct output mixer configuration for your system. That simple... Helped me figure out that the Realtek audio manager testing of speakers only works if your speakers are connected to your motherboard on each separate connector (i.e. not through coaxial or HDMI).
check the bit rate of the Desktop Control Panel and Match with Home Theatre and CODEC, they should be the same. Also check if the SPDIF connector is properly seated and with correct pin configurations.