Clearly I am taking too many stimulants then, bit of a stimulant fiend haha...
I have noticed that it is VERY much to do with volume, at mid / high volume these things destroy my ears in no time but at moderate / low volume I can use them for hours even without much EQ.
Also obviously the recording / MP3 quality makes a massive difference, high quality FLAC recordings sound pretty much smooth whereas low quality / bad recording sound vile on the HE400.
Oh yea well everything I Have is in flac, and I DO NOT like high volume! Med to low ALWAYS