Lord of the DACs
OK, I don't know if I've mentioned it before, but I've got a Chaintech AV710. It's one of those soundcards that has nothing on board but a magnificent (prosumer) Envy24HT Audio controller and 24-bit Wolfson DAC. These things aren't your ordinary sound card thingies. They're prosumer! You can get close to 100dB dynamic range out of em (CD quality is 96dB, and most sound cards aren't good enough to play that back clearly). It's impressive, considering that I dropped less than $100 on em. I wanted a Terratec Sky or Space or whatever, but they don't supply stuff in this country, and it would've cost me $400 or so to import it. It comes with Aureal or EAX or whatever 3D audio stuff is needed to make games run fast (unlike the Chaintech), but the main priority was the high quality DAC and controller. Actually, I'm not so sure you can get the Chaintech here either. A friend of mine got a bunch from overseas in case some friends wanted some.
Anyway, it's a good soundcard, but I was as yet unable to get it working in Linux, for a variety of reasons (driver support's only been recent, and there's a shitload of options with no clear way to turn on the DAC). See, the Chaintech's got an "interesting" setup. To save space on the back of the card, they've had to combine the rear channels (the extra 2 from the 7.1) to a line in or something. Point being, it's not just some ordinary channel, you've got to "do stuff" to enable it, and since it's in and out, there's no clear way to do this with linux.
To complicate matters, recent driver changes in the kernel didn't actually initialise the Wolfson DAC, because the driver's shared with a bunch of Envy24 based cards, and most don't have the odd setup. Anyway, point is, I patched my kernel but still no dice, mainly because I couldn't find what option to turn on, and the saved state files didn't work. I downloaded an updated state file, and figured what I'd been doing wrong.
You have to set "Record" to "on" in "Capture". See, "Capture" is the volume control for the rear speakers, because it's also Line in. Switch that on and turn your IEC958 0/1 channels to H/W in 0/1 and you're laughing! It sounds really good. I almost want to cry. I've wanted this kind of sound since you guys got me the Sennheisers for my 18th. :)