What does rod knock sound like?

[Philbar71]

My 2.4 has a odd knock when the engine is cold, at idle (around 800rpm). I only hear this noise from somewhere in the bottom end. Def not near the lifters or valve train.When the engine is fully warm i do not hear the noise at idle (550 rpm). However, when im driving and and the engine is under load and at about 4000-5000rpm i hear a very quick and faintnt ticking/knocking. What could be these noises? This noise eventually goes away and cant hear it again until the engine cools down.