My dad has some JBL CS 460 home theatre with an onkyo receiver, the sub stopped working, it made like crackles and a bang and cut out then came back in again and did the same thing till we turned it off, but now only the two front speakers are working, the centre speaker stopped and the two rear have also stopped working, the connections are are tight, just they stopped working all of a sudden with no warning, are the speakers broken? or is there something wrong with the receiver? We have had two of the speakers fixed before by someone who fixes speaker and was highly recommended but he has gone out of business, we live in Western Australia, i don't think we have too many people who repair speakers, i can't remember which two speakers were fixed and i can't remember the cause of them breaking either.