I hear very good, that is why I wrote what I wrote. I hear very good because I do not listen to loudness oriented types of music; when I listen to music the maximum level of loudness for me is low level loud as opposed to mid level loud or even worse, heavy metal loud. That means that my hearing is not damaged and I can clearly hear 6dB drop.
That's not the point MH is trying to make.
I think what he's trying to say is that headphones don't always sound like they measure.
Here's a question:
Does a U-shape dip that spans a range of 600hz really count as a drop? It seems to me to be more like the designed frequency response, as I would normally associate dips or spikes to span a range of 10-20hz.