So I got this idea a while back; when Vertrex and I added speed and acceleration zones in sty+ct+ap.
Speed zone = sets your speed to a specified speed while in the zone.
The idea is to have a line of speed zones (different sizes and speeds) such that the cycle noise playing out the speaker would produce a tune; a melody.

(Don't bother trying it in-game, the hosting it is on right now isn't good enough to play the songs properly)
Initial testing didn't work quite as planned; there are still some minor kinks to work out here and there.
Good news is, even though I don't have a "lag-free" server to put this idea on, I was able to get a decent preview with the assistance provided by rad (Radiuks@forums).
Many thanks to him for providing the mp3 recordings.
Enough talk! Onto the preview!
-->some mp3s play at a slower rate than their youtube counterpart, listen closely
-->Warning! The mp3 previews are quiet, remember to turn your volume UP for mp3, DOWN for youtube.
-->To give you an idea of how long the maps are, the height is 200 units (from y=100 to y=-100)
First song: I'm sure you can recognize the tune
Map Preview
MP3 Preview
Youtube comparison (0:15 - 1:42 ONLY)
Second song: SMB 3 water theme
Map Preview
MP3 Preview
Youtube comparison (only need to listen for a minute or two)
...