Well about creative they claim...

"Creative’s Sound Blaster X-Fi Xtreme Audio gives an experience beyond studio quality with MP3 music and movies! Featuring award-winning X-Fi technologies, X-Fi Crystalizer restores the details and vibrance lost during MP3 and DIVX compression, breathing life back into any audio, while X-Fi CMSS-3D expands stereo music and movies into amazing surround sound. Effective over virtually any speakers, including stereo speakers, Sound Blaster X-Fi Xtreme Audio even provides unbelievable surround sound over normal headphones!"
That's what I was saying... it's not entirely 100% true, but it does effect, the cpu changed the modulation, it kinda makes the bass sound lower frequency and the highs sound very high.
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Visual example for a comparable concept of loosing details in a block of data, no matter it being an image, a sound clip, or even text, for what it matters.
Starting only with the image on the right, do you think you can precisely take back any detail (even 1 pixel) of the original image on the left? You can't, because you just don't have the data. You can even fake or do a process called pixel binning to simulate a more accurate representation, but it's where all it ends. You can fake a wider representation of a sound clip but it will sound for what it is, a distort rendition in comparison to the original.