Ok so after a bunch of embarrasing trips to the mechanic claiming there was a knocking noise that never occured with either mechanic i took out, i think i know whats going on. I think its "spark Knock" but i need some more audio clips to confirm, and youtube only has 1 or 2 videos, will anyone help me find some recorded audio of spark knock?

Thanks

sounds like this(at the end)

 

Just seen something online saying that an dirty EGR valve could cause spark knock.