I've got a Adire Tempest in a giant enclosure (244 liters I think) and it's powered by a Parts Express 250 watt plate amp. The sub is about 5 years old and has performed like a champ up until a month or two ago. Sometimes when I turn my system on, the sub is dead. It doesn't matter if the amp is in power-save mode (where it turns off after a minute or two of no signal) or in the always on mode. When I took a closer look at what's going on, I notice the driver is oscilating very slightly regardless of what's coming in on the sub input (which is coming off the sub output of an Onkyo SR600). Now for the strange part... If I turn the power to the sub off then back on, there is no change in the behavior. If I leave power on and unplug the signal source (rca plug) then plug it back in, I get the expected loud blast and the sub starts working as normal. If I turn power off, then unplug the signal source, then plug it back in, the sub starts working as normal. Does this sound like a driver issue or an amp issue? or maybe something with signal grounding? I'm thinking amp, but I've never had this issue before. Any ideas? - James T.