How can I disconnect the audio system/speakers from the battery?

What is your question?

My speakers screech a very, very loud static sound almost non-stop even when I turn the car completely off, all of them. Instead of pulling out all six speakers and disconnecting them that way, I was wondering if I could simply snip a wire connected to the battery or fuse panels to shut them all off at once. Its a 2013 Ford Focus SE.

How long has your 2013 Ford Focus had this problem?

2 or 3 weeks