His mod inspired me to try it with my D2000 over a year ago. I ended up doing some different, irreversible mods on them that I wish I hadn't now. But I did like how they sounded when modded just like his. I put some foam discs in front of the driver (like a lot of my mods) to help with the treble a bit on my pair. I could definitely hear that peak around 4-5KHz, and I couldn't stand it. I tried to find material to address that, but I stupidly removed the damping paper/felt from the back of the driver before trying that. In combination with the foam in front of the drivers, it helped smooth out the treble (Tyll's measurement of my open D2000 actually had fairly flat treble past 4-5KHz), but it also create a very large suckout in the mids. Noticeably worse than what these graphs show, I'm sure. I haven't been able to find a proper replacement damping solution, and they're just hard to tune right in general now. This was before I had some sort of idea what I was doing, though. Oh well...

I think the open D2000/5000/7000 have interesting characteristics and could probably be optimized with some basic mods/tuning to make for a very unique, but nice open headphone.

HD measurements?

^How did you infer that?
There are no bass decay measurements here as far as I can see.

So what is the difference between the 5-6k peak here and the 5-6k peak on the HD700?

Thanks Purrin for giving them a listen. I thought they were goners for sure until somehow FedEx magically pulled them out of their ass. I’m glad that you found them tolerable considering what you’re accustomed to hearing. I know you’re busy of late, but have you heard the LA7000?  I haven’t and was wondering how they might compare. I had the original MD5000 from him before he got into Jena cables and fancy cups. Those were the ones that made him sell his Sony’s. They sounded good, but I sold them after the D7000 was released.

I know someone supposedly sent their TH900’s for the Markl mods. It’ll be interesting to see what comes of that. I feel pretty skeptical about the cups, cord and pad swap aspect. As far as dampening goes, I did peek inside my TH900’s to find that Fostex did attach big white rectangular shaped pieces of foam to the internal surfaces of the cups to address this. So I guess I’m pretty skeptical about the entire Markl deal for the TH900.

Okay, so I did more than peek inside the 900’s, I reversibly and very gently tried some mods since the process is identical to the D7K. Long story short is that mod’ing makes a drastic change to the Denons and much less of a difference with the TH900. So I quietly put things back to stock and am enjoying them as they are. Other notable differences to the Denons is that there are much bigger magnets on the 900 drivers and a thicker gauge of wire used inside the cable.

Regarding the open D7K’s, I did change the mod since the photos were taken for the thread. Currently there is tape occluding the ear pad slots where the pads would normally be attached. There is also black caulk sealing the gap between the pads and frame. In the original mod, there was even more of that open sound with a still brighter treble. In addition, there was no bass extension below approx 31 Hz. So with the new changes, the treble is more tame and bass extends to where it should be at the cost of a more closed-in sound.

So though the TH900 is a superior phone, the open D7K has that 5K bite that you described and a less congested sound that makes them a nice alternative. So between these 2 phones and my W3000ANV, I have 3 great flavors to choose from.

I’m awaiting the arrival of my new Paradox from Luis to give me more of a reference sound. If I want true reference like I died and went to heaven sound, I go to my PSI Audio A17M monitors. I do see a stat rig in the very distant future. Thanks again

Oh yeah, Tyll also measured these and commented:

“Lastly, but not leastly, a couple of DIY cans came in. A pair of open-back Denon D7000 modified by lmswjm were run through the system. They were a little sucked out around 1kHz, but frankly, with the magnitude of the mod I though they measured and sounded pretty good.”

http://www.innerfidelity.com/images/DenonD7000DIYModifiedlmswjm.pdf