Onboard audio – sound missing

Issue : Using ASUS P4P800 SLi Deluxe, on board audio – Spdif (Toslink)
to receiver and finding that windows sounds are ‘missing’

Machine Setup – Windows Vista running Media Center (SP1)
Motherboard: Asus P4P800 Sli Deluxe, onboard AC’97 audio with 6x analogue & spdif optical
CPU: Athlon XP 4800
GPU: Nvidia 7800 GTX 256
Memory: 4GB DDR2
TV Tuner: Dual Hauppage MCE OEM with IR Receiver
Remote / Input : Harmony One and Shintaro RF Keyboard with Trackball
Receiver: Denon AVR 2807 (optical input), 5.1 Speaker (B&W 6 Series)
Display: Panasonic Viera 50″ Plasma (component connectors – 720P)vista_media_center_logo

vista media center screenshotI recently converted my old PC into a media center for the lounge room. I had a Topfield 7000 set top box (great picture but more bugs than an anthill) and a Dvico TVIX 5000 HD Media Center (great for movies, very basic for music). Both devices were flawed – the Topfield with bugs galore, awful TV guide and forum members so irate Topfield closed the forum… and the TVIX, a good unit but with very basic audio functionality and stability issues when playing music off my NAS. I have my video and music content on a 2 TB NAS and so I really wanted a ‘do it all device’ for TV, recording TV, to play movies with various codecs as well as offer a flexible jukebox platform for playing music that supports playlists, ratings, visualizations, sideshows etc.etc

I set up the Media Center PC (Vista x32) so that I could hide it behind the video cabinet, and keeping my partner happy – I wasn’t allowed to turn another room into a ‘computer room’. The motherboard provides both dedicated analogue outputs as well as a spdif (optical) connector. At first glace it would seem a simple choice – connect six separate audio channels with cables or one single audio channel that does 5.1 and digital and let the receiver decode.

p4p800_audio P4P800 SLi Deluxe Audio

Spdif (black border and gray center)

Analogue (six 3.5 plugs – orange, black, gray, blue, green, pink)

Spdif – is perfect for sources with digital audio. It can transmit encoded or decoded Dolby Digital and DTS using a single cable. This allows your receiver to receive a bitstream signal(not yet separated into channels) and the receiver separates the audio into appropriate channels and and applies EQ / compression etc. as required. Media Center, PowerDVD, Winamp etc. can all make use of your spdif connector to send audio signals to your receiver. Spdif can also transmit stereo sound from Windows so you can hear the analogue audio generated by the operating system.

So why would you want need anything else?? In a nutshell – gaming and applications that generate analogue surround. Most games produce surround sound these days and they do this and can generate 6 analogue audio channels (FL, FR, C, RR, RL, Lfe). Most of the sound cards on the market will NOT transmit analogue surround sound over a Spdif (digital) connector (the exception are cards with Dolby Digital Live or similar technologies that encode into digitial in real time). If I want to hear surround sound gaming using the onboard audio of the P4P800, I need to use the 6 analogue connectors – something I’m living without (for now!)

My issue began when I realised that the volume slider in Vista was no longer making a noise when I moved it up and down. After a bit more investigation I realised that all analogue sounds were no longer being played back through the receiver. Not a big deal most of the time, but I definitely wanted analogue audio for web browsing, especially since you can watch ABC TV online now (for free if you are with iiNet). Of course you also need this so you can watch people being hurt in videos posted on YouTube and Facebook…

I wondered why spdif was no longer sending analogue noises. I checked the settings on the Spdif device settings – they all seemed ok and I could hear digital sounds. I also downloaded the latest AC’97 drivers from the Realtek web site as the Asus drivers were about 2.5 years old and labeled ‘beta’. These provided me with a few more configuration options – but still no analogue audio.

tech_tip

Solution: I realised that I had installed about three separate codec packs so I could get Matroska AVI encapsulation, FLAC, AC3 audio, H.264, Xvid, DivX and everything else I could think of. I had read that you can get codec conflicts if you install too many packs.. but then I hadn’t found one pack that ticked all the boxes I wanted. I decided it was time to tidy up. I uninstalled everything related to codecs and downloaded the latest K-Lite Codec Pack which does everything under the sun, then some more. During installation the K-Lite Codec pack provided dialogue boxes explaining that some registry entries for audio configuration had been corrupted / where pointing to non existing applications. The codec pack actually corrected these registry entries (bless their hearts!) and the volume slider (and all other stereo analogue sounds) were once again beeping away – happy days!

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