HD800 Darth Vader Rebuild + SDR Mod I feel absolutely horrible because I forgot that I had been in possession of this headphone for a few months; and only now have I finally been able to get to it. Some of you guys may know that I intentionally dissected a fully functional HD800 for "science" on Changstar about twenty months ago. (I still need to repost those findings here). This left the HD800 pair essentially unusable because the metal foil was ripped out from one side and I could not replicate the special properties of the semi-permeable foil. Those Sennheiser guys are pretty smart and possess secret knowledge that other headphone makers do not. At the small El-Lay meet, before the Big El-Lay meet, I mentioned to @Bill-P (our resident mad genius modder) that I still had the drivers and remainder of the parts to the dissected HD800. He volunteered to do something interesting for me. The turnaround was much quicker than I expected. I couldn't get to it right away, so I left this pair languishing in a box for several months. So now I present to you the Darth Vader mod. I'm calling it Darth Vader mod because @Bill-P essentially rebuild it after I broke it. I did tell that that HD800 that I had the high ground, but the HD800 did not listen. Also the metal foil has been replaced by a black wrinkly material on the outside with TP on the inside. Check out these photos: Photos are with dustguard removed. This mod REQUIRES the use of the dustguard to help maintain lower bass frequencies. Now here are the frequency response plots: Grey = Stock HD800 Purple = Bill-P mod Green = Bill-P mod + SDR mod. I actually don't mind that the bass is down a few db, the HD800 always exhibited a warmth (actually a V shaped response) that I understood was a necessary evil (to counteract its 6kHz peak). However we can see that the Vader mod reduces the peak and some parts of the treble a few db, reduces the 5kHz dip, and fills in the 1-2kHz area a tiny bit. Overall, the Vader mod evens out the frequency response across the audio band. In conjunction with the SDR mod, the positive effects are even more prevalent. See here for information on the SDR mod: http://www.superbestaudiofriends.or...nt-resonator-summary-and-interest-check.1558/ Lets take a look at CSDs to get a clearer picture of what is going on. We can see that the Vader mod does even out the response from the lower mids on up. The peak and ringing at 6khz is moderately reduced, and the ringing at 11kHz is almost eliminated with the progressive application of the Vader and SDR mods. Don't get me wrong. It's still an HD800. But I am running them balanced out of the Schiit Jotunheim (with Modi Multibit DAC fed by a CDP) and not having a problem! This says a lot since I have gone on record as not recommending the Jotunheim with the HD800 or any of its modded variants.