I recently purchased the Polk CSM center channel speaker to replace an Onkyo center channel speaker that came with my HTIB Onkyo 780 system. When I turn up the volume loud the onkyo amp keeps cutting out. I rarely had this problem with the Onkyo stock center speaker and it could also play much louder before cutting out. It appears the Polk is rated at 4 ohms and the Onkyo may not be able to handle them. The onkyo manual states not to use 4 ohm speakers as they might damage the receiver. The polk spec sheet states that the nominal ohms is 4 but that it is compatable with 8 ohms output. Does anyone know what that means? Does it mean that it should be compatable with an 8 ohm only receiver? Does anyone know if I could end up damaging my receiver because of these speakers? Why would polk create a budget center channel speaker rated at 4 ohms when most budget receiver cant handle that type of load?