Originally Posted by velocitydreamer
First off, thank you to anyone who can lend a hand... all helps appreciated, whether the advice works or not.
I am currently using Windows 7 Ultimate 64bit and I have an ASUS p5q and am running a power color hd4870 1gb. I installed the HDMI 2.67 Realtek audio driver and the latest ati catalyst 12.2. I am currently using the dvi-to-hdmi adapter and running it directly into my 7.1 receiver, and then out to my tv. There are two problems I run into. First, after a short bit, I start getting a random/sporatic popping/crackling sound that happens about once every 2 seconds throughout every speaker in the system. I've heard of such an issue, but never really found any resolution that worked. Second, I CANNOT get an HDMI driver that will show 7.1... I've found 5.1 through the ati audio driver, but everytime I go into the windows speaker configure (and the realtek driver, though the realtek driver doesn't actually work and only shows stereo in configure speakers) I only have the "stereo, quadrophonic, and 5.1" options... this system is perfectly setup for 7.1, speakers and all... there's no reason for it not to work. So, when I set it to 5.1, I click next and the side speakers are greyed (might be rears... SHOULD be rears)... so yeah, objectives: get rid of crackling sound and enable 7.1. If I can remedy these two problems, I will be in heaven
All help is greatly appreciate guys & ladies. I really want to find a resolution...
First of all, you're probably in the wrong forum. The HTPC forum would probably be of more help since none of what you described is an HDMI issue.
I suspect your first problem is a driver issue or interrupt issue, although interrupt issues like that should have gone away with modern boards. I'm not sure if I can help you with that issue.
The second issue requires some background knowledge. On the back of most motherboards (these days) are 7.1-channel analog outputs. These ports have a dedicated audio output for each audio channel - actually usually done in pairs (front channels, center/LFE, surround channels and rear channels). So sending out a 7.1-channel signal, in this case, is just a matter of the audio board routing the right signal to the right port. Very simple.
Now when you send 7.1-channel output to the HDMI output, that audio has to be encoded with the video into essentially a single output stream that goes across the HDMI cable. There are no dedicated audio lines - it's all a digital stream.
In order to do that the audio needs to be encoded into a format that can be sent over the HDMI cable and then decoded on the receiver side. With surround sound for many years, this encoding could only be done as a Dolby Digital or DTS output. Dolby Digital and DTS were 5.1-channel outputs, with the exception of the (unfortunately) rarely used DTS-ES (6.1) and Dolby Digital EX (a 5.1-channel with a rear channel matrixed into the surrounds). LPCM was usually reserved for 2-channel at this time.
Along comes Blu-Ray and adds dedicated 7.1-channel output in the form of Dolby TrueHD and DTS Master Audio (DTS-MA). In addition, LPCM can be used to send 7.1-channel audio over HDMI. So, those are the options for true 7.1-channel audio.
Now to get this across the HDMI cable, the sink (your receiver) has to tell the source (the HTPC) that it can support 7.1-channel. So you need two things - an HTPC that can output 7.1 and a receiver that reports it can accept 7.1-channel audio. The 7.1-channel audio can be in the form of LPCM, 7.1-channel Dolby TrueHD (not Dolby Digital) or 7.1-channel DTS-MA (not just regular DTS). If you can't output those, then no true 7.1-channel unless you use the HTPC's analog audio outputs. To use the analog 7.1-channel audio, you simple need a receiver that has 7.1-channel analog inputs.
From your append, it appears that the HTPC's drivers do not support sending 7.1-channel audio over HDMI and would instead use a 5.1-channel signal (what format?) and allow the receiver to derive the back surround channels from the surround channels. The other thing you need is a Blu-Ray player (or game software) that can support 7.1-channel ouput over HDMI. Basically if your source doesn't output 7.1-channel, you can setup the rest of your system perfectly and you still won't get 7.1-channel audio output.
Here's an article about 7.1-channel audio over HDMI:http://www.anandtech.com/show/2622
Hope that helps. There is a very active HTPC forum on the AVS Forum who can probably help you with the driver issues.