I stumbled across a really useful program I think you all might want to try too.
Have you ever wondered what is the true audio quality of your sound card? I know I have. For instance, how does my sound card compare with a high-fidelity stereo? (Or maybe the question is, how much worse is my sound card than a high-fidelity stereo?

)
For instance, what is the signal-to-noise ratio (SNR), the total harmonic distortion (THD), the overall frequency response, etc? That's extremely useful information to know, especially if you have ever used your sound card to record old cassette tapes/records into digital format like I've done before; and that's something I've never seen spec'd in any of the manuals that came with my computer.
Well I actually stumbled across a program that does this called "
RightMark Audio Analyzer":
http://audio.rightmark.org/products/rmaa.shtml
Note that the test results it returns are for the combined playback and recording quality of your sound card, because unless you have more than one sound card, the program uses the same sound card for both playback and recording obviously, and the results cannot be separated. I would also recommend downloading the manual too when you go to the download page, because it is not included with the program by default.