My wife’s computer (which is now our DVR system) has a (Dell OEM version of the) Sound Blaster Audigy 2 ZS, which includes a port labeled “Digital Out”. I wanted to connect it to the surround sound system I have, which only has a single digital input, labeled “Digital Coax”. I thought that I might need to get the Digital I/O Module and a digital coax cable, but I wasn’t sure that would work, since the sound card model isn’t explicitly listed there, although I suspect that it would. The digital out itself is kind of odd, since it’s really three separate stereo SPDIF outputs, to get 6 channels out, and the sound card didn’t support the normal AC3 encoding over one output to a receiver, although it could pass through an original AC3 source (like a DVD, or, I hoped, a HD recording) on one channel.

But, some people on some forums on the Internet that came up when searching for what I was looking for suggested that all I really needed was a way to connect the mini-jack connection on the sound card to the RCA-style jack on the surround sound system, and that the cable itself wasn’t very important for the short distance that it’d be run. Some claimed success with a stereo-to-dual-RCA adapter and just plugging in the left/white output to the receiver, although I saw somewhere somebody who said they needed to use a mono-to-single-RCA adapter.

So, yesterday on the way home I stopped at a large store and picked up a stereo adapter (which wasn’t easy to find), plugged the little end into the sound card, plugged the white output into the digital input of the receiver, switched the receiver to use the digital input, and much to my surprise suddenly my sound was working through the receiver in stereo.

To get surround sound working, I installed AC3Filter to use as my sound renderer, set it up to pass-through AC3 input directly to the digital output, and all of a sudden I was getting surround sound when watching or playing back HD recordings. When playing back a normal stereo recording (from analog-recorded shows), it translates the audio into 5.1 in a reasonable way, although I think I can tweak it to improve it.

The whole process was much easier than I thought it would be.