Ok, I know it is probably a stupid question, but what exactly does knocking/detonations sound like?

 

If you mean pre-ignition, I have always thought it sounded like marbles bouncing around in a tin can. There is no pattern or consistency like a bad lifter or bearings which get louder and more frequent as the revs increased.

About the only thing consistent is that it appears when you have a load on the engine, like giving it a little extra gas when climbing a hill.