what is the rattle sound which seems to come from catalytic converter area?

sounds exactly like the problem, will check out, thanks

i know someone that is going through that.thought it was timing chain first,then thought it was rod knocking,cause it got louder.lost power going up hills,would not go over 40 mph with pedal on the floor,very little exhaust coming out of tail pipe?now it has stopped,but that is his problem,it will start back doing the same thing,once it moves again inside the converter.

thanks, I will have it checked at a garage tomorrow