Tiemen
Headphoneus Supremus
It's reasuring that you say you can endure this headphone for hours when you have tinnitus. Yeah I know these are different compared to what I'm used to. I have severe tinnitus so that's the reason why I'm moving to darker headphones. I'm sure I can get used to the soundsignature over time. I have to. Bought DT150 for closed and HD650 for open untill I figure out what planar I'm gonna buy. Still doubting that the treble on the HE-560 gonna suit me but I will try them at some point. Otherwise I'm just gonna have to wait untill new ones are made.
If you are after a darker sounding, non fatiguing planar with a smooth treble, you should also consider the ZMF.