I received a nib pair of Nighthawk Carbons today. After reading about the 150 hour burn in, I was amazed by how good that they sounded right out of the box! They sounded just a little muffled a few times, but I am thinking once they get loosened up a bit, that will go away. What should my expectations be about how the sound changes over the 150 hour burn in period? My burn in routine is to plug them in to an old boom box tuned to a 24 hour FM stereo station and give them 23 on and 1 off every day.