Audio Systems: Subwoofers woofing?, subwoofer amplifier, cvrs

Question
I have recently bought 2 12' kicker cvrs and had them installed into my car.  My problem is that i have been playing the subs quite often and all of a sudden they just started to start thumping like a heartbeat, even when i turn them off. If you have any knowledge of what is going on i would gladly appreciate a response.

Thanks again,
Shane

Answer
You might have NOT turned them off.  Are you certain they were installed correctly?  There are two 12v lines that connect to a subwoofer amplifier; one is for constant power that remains connected at all times. The other is from the ignition or head end that is for turning ON the amp.  In your case I suspect the 12v ON line was hardwired.

The thumping that continues is usually from a bad ground connection.  The ground connection for the sub amp(s) must be a solid metal to metal with a very tight resistive connection or it can cause what you are experiencing.

So, there are two possible problems that must be corrected. Give it a try and let me know if you need more.

Cleggsan
PS: A shorted voice coil in one of the woofers can cause this, too.  Try disconnecting each one, one at a time to see if it quits when doing so.