The Creative XMod plugs into your computer as a soundcard and the company claims: "X-Fi module for PC and Mac restores MP3 music beyond studio quality". "The Creative X-Fi Xtreme Fidelity audio processor puts your music and movie audio through a two-step quality enhancement process. First it converts the audio into 24-bit/96kHz quality, then it remasters and selectively enhances the audio by analyzing and identifying which parts of the audio stream have been restricted/damaged during the compression stages to 16-bit and then to MP3. The result is music that sounds cleaner, smoother and has more sparkle, and movies that sound more realistic than ever before!" as reported by MusicBlog.
I wonder how they accomplish this engineering wonder. If true, I can produce MP3 libraries - and just run them through this gizmo for better than studio quality sound. Hmmm.....
Seems highly dubious. If I understand how compression works at a fixed compression rate, say 7:1, only the first 7th of the waveform over each sample period is retained and the rest discarded. There is no way to bring this information back "correctly". I suppose one could repeat the current sample six more times with minor variations in pitch, amplitude, and harmonic content to sort of fake the original waveform, but it would be a crude approximation at best, though I suppose it may subjectively be an improvement over the unprocessed mp3 file (or maybe not).
I have found the mp3 acid test is anything with the sound of rainfall in it. There are many extremely rapid transients in rain, and they are so random that if interrupted by the compression sampling process, the result ceases to sound like rain. For example, I have a couple mp3s of The Doors Riders on the Storm, but the rain always sounds like someone tearing paper in half! I don't think this is what Jim Morrison had in mind (8^D). The loss of high frequency transients and waveform coherence is also frequently noticeable on things like cymbals, traingle, tambourine, etc., and progressively noticeable the higher the compression ratio. And this is not just an mp3 thing either, as the cd masters of these same sampled waveforms to my ears always sound inferior to their analog counterparts as previously released on tape or vinyl. So, it's bad enough that everything is now released in digital form, but then the whole mp3 thing further and sometimes drastically degrades whatever sonic experience was originally present.
It may be no substitute for the original uncompressed sound, but for music that has already been compressed it may provide a nice improvement.
Of course words like "beyond studio quality" seem pretty darn subjective anyway. Um... I'm not sure "experience" can be graphed like that... ha! That's funny... "Well, gee, at first I didn't believe this whole thing, but I took a look at the graph and it proves it right there!"