Question about the 15 minutes demo track

[FeelingGood]

I have downloaded the 15 minutes demo track and downloaded it to both my ipod and my wife's. I understand that this track is compressed more than the actual product, but when I play it on either of our ipods, there is a low frequency popping sound throughout the recording (actually it only start about 1 minute into the recording) which is NOT there when I listen to the same track directly from my computer with iTunes. This popping sounds like pop corn popping muffled by a pillow... how's that for an analogy?

Any idea what would cause that distracting popping sound?

[jodie]

Do you have any graphic equalizers or extra bass or treble switched ON on your iPod?

This is the only thing I can think that this is if you are hearing the files okay from your PC.

Jodie