I should do it some time, though. Tricky thing is if the results from microphones are particularly representative of what you hear.
I have an iPhone app called Aware that picks up environmental noise through the inline mic in your earphone cable and feeds it to you. I tried it because I thought it might be useful but I found it distracting to the point of making me feel slightly nauseous. (It's a bit like watching a film when the sound and pictures aren't properly synched.)
If sound information is to be at all useful to you when cycling, you need to be able to discern the direction it's coming from. Now, I find that you can't trust the directional cues you get from environmental sound*, which is why I personally don't consider hearing useful when cycling, but when that sound is being reproduced digitally by your phone rather than coming from the world around you, it loses what little directional information it may have had and becomes entirely useless.
For that reason, I doubt your experiment would be helpful.
d.
*YMMV, but I cycle in the real world, not in an anechoic chamber.