(Sorry for the long post. It is my first after many months following this site.)
I purchase the Denon AH-D2000 headphones in March 2012, and since then I have been studying posts here and experimenting with modding it. I'm now very satisfied with the sound quality produced by these headphones and undecided whether I should mod it further or invest in other equipment.
I usually stream audio from an iMac through an Airport Express to the Naim NAC92-NAP90 preamp-amp, and from these to the Denon headphones using JDSLabs' cMoyBB 2.03 headphone amplifier (there is no headphone output in the Naim combo). Basically, my question at the end of this post is: would I experience greater gains in sound quality from purchasing budget, but state-of-the-art, DAC plus headphone amplifier, or from performing other mods on my Denon? Because I learned a lot from this site, and because there is still a lively debate going on in this thread, I also want to share some of my modding experiences. Those who are not interested can still help me by answering the question at the end of the post.
For those who might be thinking of modding their own Denons, my brief advice is to trust the opinions of markl, the originator of this mod, both in his original post and in his company website:
http://www.head-fi.org/t/299627/how-to-build-one-of-the-worlds-finest-dynamic-headphones-markl-denon-ah-d5000-mods
http://www.lawtonaudio.com
In my opinion, markl has been very accurate in describing the sound improvements resulting from the various steps of his modding procedure, at least those that I have followed. Yet, I think that there is an important step to improving the Denon's original sound, which was suggested by others, but not endorse by him (see step 4 below).
The mods that I did were (1) replacing the original D2000 plastic cups with D5000 wooden cups (purchased from Lawton Audio, with the damping material FatMat applied inside), (2) damping the back of the drivers as well as the front faces of the driver plates (with the same FatMat material, purchased as a kit from Lawton Audio), (3) stuffing the original pads to optimize the distance and angle of the drivers in relation to the ears, and (4) inserting a sheet of perforated felt between the driver plate and the metal frames where these are mounted.
For performing step 1, I consulted the following threads:
http://www.head-fi.org/t/502070/how-to-create-a-d2000-woody-on-a-budget-56k-warning
http://www.head-fi.org/t/496457/denon-d2000-d7000-wood-cup-swap
My suggestion here is to cut the plastic poles of the D2000 driver units, instead of drilling into the wooden cups. This last procedure, in my opinion, is more complicated than suggested in those threads. The drill bit I used had a long and sharp point, which is useful when drilling into wood, but almost led me cut through the other side of the cup! I realized tiny marks on the external surfaces of the cups only after drilling into them. Luckily, that was not sufficient to create a hole in the varnish. The other problem I encountered with this procedure was that the I whole created was too deep for the original screws to attach, or for any others that I could find. I had, then, to cover the holes with a type of wood putty and switch to the method of cutting the plastic poles. With new screws that could drive into the solidifying wood putty, the problem was solved.
In step 2, I followed the complete instructions provided in the following link (including the optional step 7, covering the driver plates entirely):
http://www.lawtonaudio.com/page55.html
In step 3, I did not use fiber loft, as markl did, but foam rings instead, as discussed in this thread:
http://www.head-fi.org/t/558782/denon-d2000-d5000-d7000-stock-pad-mod-for-wider-sound-stage
What is striking in this step is how much subtle changes can affect the sound! Like many others in the thread above, I noticed increased sibilance, which was (partially) solved only with step 4, below. Overall, in my experience, sonic changes due to pad variation can be summarized as follows. Angling the pads forward positions the music more in front of you, rather than aligned with an imaginary plane crossing your head from left to right, so to say. It also increases the depth and layering of the soundstage. Making the pads thicker, thus more distant from the ears, reduces the volume of the bass and the treble, but increases sibilance as noted above. This change also makes the soundstage less wide yet more coherent, i.e., without the left, center, and right "spots" that people say are common when listening to headphones. It's easy and cheap to experiment with pad changes. I eventually settled with a solution that I believe is close to the distance and angle provided by the Angle Pads, from Lawton Audio. Unfortunately, I do not own them for a comparison. But, considering the distance from where my pads touch the headphones' metal frame to the stitching on their pleather, the back side measures 30mm and the front, 17mm.
After these mods, the headphones became substantially better in several ways: bass and treble, more in line with the whole frequency curve; soundstage, more coherent; instruments and voices, better demarcated; sound positioning, more out-of-the-head; and timbre, more realistic. Still, I could not feel completely comfortable while listening to music, because of the added sibilance. I tried placing a piece of foam in front of the drivers, as discussed in this thread: http://www.head-fi.org/t/450631/a-trick-to-get-less-treble-and-sibilance-on-markl-modded-denons. Doing so reduced the treble and sibilance, which was good; but also reduced clarity and increased the bass, which was bad. For me, better results following this line of thinking were achieved with sheets of two-ply toilet paper or paper towel.
So, in step 4 of my mods, inspired by a few other head-fiers, I covered the face of the driver plate with perforated felt. The principle behind this is to reduce the reflections in the higher frequencies that are supposedly caused by the shinny surface of the damping material applied. As far as I know, some people have covered the material inside the cups as well. But I wouldn't dare to fiddle with that part again! In order to cut pieces of felt with the proper dimensions and add all the wholes that are distributed on the driver's plate, I used the following template: http://www.head-fi.org/t/352109/markl-mod-made-easy-d2000-possibly-for-d5000-template
Thus far, I think this is the best solution for taming the sibilance in my markl-modded Denon. To my ears, the treble is the only part of the frequency curve that was affected by this mod. I do not have measurement equipment to test this, but I would suppose that it is decreased in some dBs in the areas where the Denons are know to have peaks, around 5-7kHz and 10kHz. I think I can hear more instrumental details in the higher frequencies, which were before smeared and too loud. Moreover, the sibilance has diminished a lot, which means that I can now more fully enjoy the undeniable benefits brought by the markl mod. I continue to dream, however, that the sound produced by these headphones could still be improved in terms of better texture in the bass area, greater soundstage and separation of instruments, and smoother treble with no marked sibilance.
So, here comes the question… If I were to improve my budget sound system by spending, say, 400 dollars, what would be the best option?
(A) To continue modding my Denon (adding custom wood cups, changing the cable, applying alternatives to the felt, etc.)
(B) To get Schiit's Modi-Magni/Vali combo (or another headphone amp and DAC)
(C) To save the money for a more substantial upgrade
(D) Other (please specify)
Thanks in advance!
. I wish I had a stock D2K next to this so I could go back and forth and really be able to tell what else is different. OH, and they're heavier. They aren't weighing down my head, but they are noticeably heavier when I hold them in my hand. I have everything tightened down very well and they are very sturdy. I had to replace some of the screws because the stockers weren't long enough. Nbd. They're 2mm screws, I got a bag full of assorted lengths from Radio Shack.
