The best (and simplest) explanation I have ever seen is similar to what Elizabeth describes above. The comment that I read said that, ultimately, no matter what conversions, etc. happen in between, the musical signal is modulating the AC power coming into your system. It just makes sense that the cleaner this waveform is, the cleaner the output will be.
I can tell you that I thought I had pretty good power until I bought a Furman 15PFi (a smaller version of Kijanki's model) to clean up the mass of cables behind my system. I was stunned at the difference it made. I don't remember what I was listening to after the install but it was something relatively familiar. My daughter walked through the room and commented that she "never knew that song had a guitar in it." She was right - I had never heard it before either. I can tell you that I'll never be without power conditioning of some sort again. And the Furman is not a super expensive piece.
I can tell you that I thought I had pretty good power until I bought a Furman 15PFi (a smaller version of Kijanki's model) to clean up the mass of cables behind my system. I was stunned at the difference it made. I don't remember what I was listening to after the install but it was something relatively familiar. My daughter walked through the room and commented that she "never knew that song had a guitar in it." She was right - I had never heard it before either. I can tell you that I'll never be without power conditioning of some sort again. And the Furman is not a super expensive piece.