Shure SRH840 serviced me nicely in early times of "discovery". They are my reference for all intents and purposes. I just play Van Halen's "Push Comes To Shove" and all becomes clear and they are the yardstick.
Metalhead here. +1 SRH840. Original Grado SR80. Senn HD485. I like AKG K240 Studio as well but those love juice so I use a Fiio E17 with it and my ipod classic. Metal is a tough genre for headphone love that's for sure.
That's the caveat of high end headphones. To get the most out of them you need more power and a great source otherwise they will disappoint in most cases. I've been there myself a few times. A good lower mid phone could do wonders with your setup. HD598 os very good.
Great comparison. Thank you. I used to own the 238s but I did not like them at all. Way too laid back for me. I would take the PX100 over them any day. I have been considering the Panasonics for work but leakage could be a problem.