I have a Denon 3803 & an Axiom EP-175 both 1 week old. For some reason today the sub channel from the receiver or woofer itself starting dropping out after every 5 to 10 minutes. To get it back on I have been going to set up of the receiver and running the channel levels set up test. When it gets to the sub W it goes back on but only stays on for a short time. How do I know if its a problem with the sub w or the receiver.