CHANGSTAR: Audiophile Headphone Reviews and Early 90s Style BBS
Lobby => Headphone Measurements => Topic started by: Marvey on November 16, 2012, 05:04:13 AM
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Imswjm is my hero. You've got to have guts to do this: http://www.head-fi.org/t/464640/denon-ah-d7000-open-back-modification (http://www.head-fi.org/t/464640/denon-ah-d7000-open-back-modification)
(http://www.changstar.com/index.php?action=dlattach;topic=639.0;attach=2609;image)
Long story short: He sent them to me for measurement via Fedex who lost it, but the box somehow made it to my house a few weeks later. Go figure. And I thought some illegal aliens swiped it too.
Couple of points / subjective impressions (going through 14 test tracks very quickly):
- I can't stand most D7000s. That ringing razor of death at 9k surrounded by 6.5k/13k double-penetrator action hurts my ears. Can't stand to listen for more than 8 seconds.
- Oddly enough, this modded pair does not exhibit this nasty treble behavior. It possible that Anetode just happens to get the T1 and D7000 rejects. I'm not sure if this is the result of the open mod or product variation. Tyll has measured two D7000s, and their frequency responses were slightly different.
- The modded D7000 does sound like there is a tizz near 10kHz at higher volumes. But it doesn't sound too bad and very tolerable for me. At 10k, the ringing, if any, seems moderate and not out of control.
- There's still a mid-suckout, but it seems less prevalent. Hard to describe. Don't get me wrong. This open-backed mod still has the U shaped curve.
- It's still just as bassy. And the bass quality isn't that much better than stock. I guess the TH900 drivers are indeed something special.
- Indeed more open sounding.
Measurements coming up.
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Denon AH-D7000 Open-Back Modification Measurements
Compare with D7000: http://www.changstar.com/index.php/topic,29.0.html (http://www.changstar.com/index.php/topic,29.0.html)
It makes sense now.
- Note: 5k ringing tends to be more benign IMO. See this for explanation (probably needs to be updated): http://www.changstar.com/index.php/topic,71.0.html (http://www.changstar.com/index.php/topic,71.0.html))
- Nice thing about 5k is that it adds an edge of a bite.
- Bass to mid transition is smoother than stock D7000.
- Sharp 9-10k dip is really a peak in disguise.
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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?
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The bass now looks like it decays a little too quick.
Clean. But dissipates a little too quick.
Still. Everything looks neat now. Like a smartly combed hair on a gentleman.
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^How did you infer that?
There are no bass decay measurements here as far as I can see.
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^^Isn't this a good thing?
It's still just as bassy. And the bass quality isn't that much better than stock. I guess the TH900 drivers are indeed something special.
This! When I'll be done with with my Kotori 201 (http://cdn.head-fi.org/5/57/57264da3_DSCN8464.jpeg), either because I'll have upgraded in the Fostex line up or become tired of the hot pads / closed nature of it, I will carefully extract and lock its drivers inside my full-aluminum Magnums and enjoy real deep, open-back bass in the Grado form factor.
Those Foster closed-backs to me are now even more open-back like, in their nature and functioning
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So what is the difference between the 5-6k peak here and the 5-6k peak on the HD700?
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HD700 has more extreme behavior:
- Trough to peak is about 14db at 5.5k.
- The slope or rise of the HD700 is quite steep and extreme.
- Has a follow-up dip and a peak at 11k which is also quite steep with a 10db rise.
- (note the HD700 graph is more compressed and on a 36db scale, so it looks slighter better than it is
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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
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Hey Hans, sorry it didn't work out. Your thread had a pretty good run for a while though...
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Hey Hans, sorry it didn't work out. Your thread had a pretty good run for a while though...
Lol, no worries! I stopped paying attention to my D2000 once I started messing with the T50RP. Now that I have a Paradox in my collection, the D2000 really gets no attention.
It's not that I dislike how my D2000s ended up. It's just that in their current state, they're very hard to tune properly and only seem to work well in a couple different, specific configurations. I just wish I had not made some of the permanent changes that I did, because I probably could have taken the mod further otherwise. Oh well! My pair only ended up having a couple of specific problems. It has a pretty bad midrange suckout around 3-4KHz and the bass disappears quickly below 30-35HZ. Everything else worked out really nicely, though I wouldn't recommend anyone go down the path I did with mods!
Would you mind uploading some pictures of your current D7000 mods once you get them back? I'm very interested in actually seeing the changes you've made since your original mod in pictures. Also, are you using any sort of foam in front of the drivers? That can really help tame the treble as well.
As for the TH900, I'd like to see the internal damping. The D2000 came stock with some internal damping as well, where as I believe the D5000/7000 did not. Just curious to see what the TH900 has going on inside!
Edit: Took a second to compare the CSD between the modded and stock D7000. Wow. Open is so much cleaner overall, though I do wonder why one channel is noticeably better than the other.
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Denon AH-D7000 Open-Back Modification
Harmonic Distortion. Nothing unexpected. From experience measuring various mods, I suspect the stock D7000 would have similar figures. In comparison, TH900 has better bass distortion performance.