Ok @matto, i just tried those tracks again with the ie8 & the ie7 with the same tips and volume setting, the bass on the ie8 minimum setting was about the same as the bass on the ie7 , the midrange and vocals were quite a bit more forward and brighter and more understandable on the ie7.
I also tried those songs with the hje900 ,same volume but with comply tips on and it was very a similar bass quantity and quality as the senn ie7 and midrange was brighter and more forward than the ie8 but not quite as much as the ie7 .
Over all if i wanted to listen to these tracks and follow the vocals i would use the ie7 ,but if i just wanted bone crushing bass i would use the ie8 and turn up the bass nob ,your ears would most likely turn to jelly though ,he he
what source (player) are you using ?