This post might seem a bit noob, considering that I've taken so many physics classes. But in trying to fix my Logitech X-240 speakers (a nice cheap buy on Slickdeals if you can find 'em), I found out something pretty cool - the effect of electromagnetic interference on speakers because of induced current in the speaker input cables. The current creates an errant, high frequency (thus the buzz) signal in the cables on the way from your device to the output. Since I got my new laptop, I haven't been using my AC-powered external hard drive much. This afternoon, while listening to music, I turned it on and later realized that they were buzzing. It took some forum searching to find out that devices around the speakers and not just cable-crossing could mess this up.
To turn this into something bigger that it is.... many times we tend to thing that things don't matter or that once something is dealt with, it's done. Like deleting a file - it's still there (try Googling "ghost bits"), or the effect of phytochemicals on fad diets, or in this case, how cable clutter under your desk actually affects your speaker sound quality. Interesting how things are interdependent.