Clipping and distortion, most likely. Lots of stupid people getting the Momo's and cranking the gains on their flea-market grade "2x150w rms" amps and turning the volume up past the point of distortion on their HU's.well i think polk it is
but now what is this i am hearing polks are easy to blow and blow on not much power
Heck, you could probably get a decent 4x75-100w rms amp and run the Momo's active and they'd perform better than if you were running them passively on a 2x150w rms amp.
