Surround Sound AC3 on an HTPC

Over the weekend I mounted the speakers from our surround sound system and have since become very interested in getting not just good sound, but GREAT sound out of my HTPC. Here’s some of the info I came up with.

Basic AC3 overview:
AC3 is the audio file type used on most DVDs to carry the surround sound. If you use AutoGK when you’re compressing .vob files you should see a couple audio options that have 2 or 5 channels (or more depending on the DVD). These are AC3 files. They are audio files coupled together with an MPEG2 video file to make .vob files on your DVD. (note: you can have multiple AC3 tracks within a .vob file). Anyway, on my system I wanted AC3 5.1 channels (which means 3 speakers front, 2 speakers back, and 1 woofer). These AC3 files tend to be significantly larger than an MP3 stereo mixdown (compression) but would be worth the space for the quality IMO. If you are looking for good sound but don’t need the bells and whistles then definitely go with MP3 for the space. Also, in case you’re curious, Dolby Digital is a type of AC3 that requires Dolby codecs to read (pretty standard on newer surround sound systems). DTS is a different kind of audio file which is similar to AC3, though not as common.

Here’s what you’ll need to get surround sound on your HTPC

Hardware:
1. YOUR HTPC SOUND CARD MUST HAVE SURROUND SOUND CAPABILITIES! If you are not sure if yours does you should check the documentation on it. If you don’t know which sound card you have then
go to Start > Run
enter: DXDIAG
click run to open the DirectX Diagnostic Tool
click the Sound tab and you should see your sound card there.
Alternatively, if you do not have a sound card that will push surround sound then you can pick one up or a external USB solution for ~$30. The USB option will just plug into your computer and provide you with a surround sound out (Dolby Digital or DTS).

2. A surround sound system (obviously) (4+ speakers and a console that can process and push surround sound audio) – I have a Sony dream system.

Software:
Your media player needs to have AC3 capabilities. – I recommend installing AC3 Filter (downloadable from www.ac3filter.net) which should work fine with most HTPC media players though most, like Windows media center, should come AC3 enabled.

That should be it. If your PC is connected to your surround system correctly you should hear surround sound coming from all 4+ speakers in your system. To test this try playing a newer DVD with Dolby Digital surround sound. If you want to keep compressed files from your DVD on your HTPC with AC3 surround sound audio then when you are compressing them you need to select an AC3 track without compression (this is easily done in AutoGK by selecting the track you want in the Audio Tracks box then selecting “original” for the output audio type in the advanced settings). The file will be bigger but the sound will be better (and coming at you from all sides)

Luck!

Richie