Graph of the new M50x versus the M50. : r/headphones
Archimago's Musings: MEASUREMENTS: Sennheiser HD650 (~2010-2012) and HD800 (~2010). A comparison of two "Reference Class" headphones, and a look/listen to the "Sennheiser veil / darkness". [Inexpensive 2TB SSD and inflation in consumer electronics...]
SoundID Reference for Headphones | Download Only – Sonarworks Store
I inverted my graphic eq based on Headroom frequency response graphs. . . does that work or am I way off? - Thread Gallery | Headphone Reviews and Discussion - Head-Fi.org
SoundID Reference for Headphones | Download Only – Sonarworks Store
HeadRoom Total BitHead headphone amplifier Measurements | Stereophile.com