I have heard this as well with my current vp100. I only heard it once during a Metallica song. I also was not listening very loud, but the popping sound was *very* annoying.

Luckily, I got upgraditis before my 30 days were up, and I'll be getting the m22's and vp150 next week to replace my current vp100 and m3ti's...I hope that it won't be happening on the new set.