I bought a centre speaker which seemd to work for some time and then sound stopped coming out of it. I swapped it over for my Dali Vokal 2 which I know works but still no sound. On this occasion i accidentally swapped the negative and positive wires around so not sure if that did anything to it? I also have another Dali centre speaker and that doesn't work either - must be the amp I have concluded. Any ideas how i can test the amp or do i need to do the auto setup again using the remote thingy that came with the unit?