Headphone.com does a nice job of measuring headphones they sell. They've measured and published the graphs for the Hifiman, Audeze headphones in question as well as pretty much everything else. I just checked the curves for my Ultrasone Edition 8s. Still trying to figure out how to reconcile 50 and 500 Hz square wave response with what I hear. FWIW, they also publish frequency response, harmonic distortion, isolation, and impedance curves.