@arnaud: Black: "Rigid Plate" Left Channel Blue: "Rigid Plate" Right Channel Yellow: "Anechoic Plate" Left Channel Red: "Anechoic Plate" Right Channel The rigid plate consists of a CD-ROM with a 2mm piece of non-porous kids construction foam adhered to the top of it. A hole of sufficient size is punched to allow the end of the microphone wand to fit flush with it. The headphone has "Anax mods" consisting of 2mm pieces of non-porous kids construction foam adhered to the metal ring and exposed plastic portion inside the headphone. The original plain HD800 impulse response file I sent you was of the left channel. Yup, that's right. Sennheiser's driver matching is nothing short of amazing. Now you understand why I don't like running rigid plate or dummy head tests. The results stray too far from perception. Although the calculations are mathematically fascinating, it's just too inconvenient to create specific HTRFs for each type of headphone enclosure; not to mention the combination of individuals' variables for each headphone. Of course the hard part would be to determine what the real "earcup" average is, if that is even possible. IMO, the real earcup average are actually the anecholic plate results - the modded HD800s sound exactly like that to me: warmish with valley in the high-mids and energetic throughout the entire treble. With the Anax mods, my HD800s have that 5-6k peak totally suppressed. I will send you the impulse response files out-of-band. One of these days I'll get another Panasonic measurement mic and shove it in my ear.