Wow, you can listen to four mp3's at once? Have you overclocked your ears? :)

It can actually be quite good to listen at four tracks at the same time. With some practice, you can focus on a single one, or all four simultaneously.

Besides, after listening to four mp3's, a single mp3 without all the background noise sounds even better :)

U28geW91IGNhbiBhbGwgcm90MTMgY
W5kIHBhY2soKS4gQnV0IGRvIHlvdS
ByZWNvZ25pc2UgQmFzZTY0IHdoZW4
geW91IHNlZSBpdD8gIC0tIEp1ZXJk