not sure that a pad change can modify the situation if he doesn't like the sound sig so much......
Pads are part of the acoustic environment, and may change the sound sig in similar way (but to lesser extent) as a listening room is changing the sound sig of speakers. You get air volume, shape, damping mass, acoustic impedance, reflections etc. It is mostly the harmonic structure that may change, the FR to a lesser extent, though it may be subjectively enough for a change. Like listening rooms don't make bad speakers sound good, pads won't make a bad headphone sound good, but may make a good one sound great, and that seems to be the case with the D7200.
There are a few headphones - like the D7200, TH900, Hifimans etc - that sound acceptable or even good without pads to start with. They will "like" thin pads and are easier to fine-tune.
Others - like Stax 007 and other electrostats - sound absolutely crap without pads: they need to be designed in a specific way.
In the case of the D7200, IMHO the midrange ringing should be handled by cups damping, but in my experience it may be tamed by inserting a 2-3 mm thin wool felt or carbon foam piece (about 15-25 mm each side) under the front part of the pads.
But you are right that the basic sound sig comes through anyway. Which IMHO is not bad at all with the D7200. The original pads sound darker, with more midbass, and with some midrange ringing or honkiness that is annoying with bright piano recordings.
What I am listening now:
- Chinese pads, directly glued to the housing with double sided adhesive (non-marking, de- and re-mountable)
- 20x25x2 mm thick carbon foam piece under the front part of the pads
- very loose Twaron Angelhair in the cups (one can skip this).
Occasionally I put back the original pads with the original plastic rings but I usually change back soon.
The end result is very pleasing, linear, with bigger sound stage and more immediate, more enjoyable sound.
In comparison, my modded TH900 is more colored, but somewhat more refined, with higher sub-bass impact and more treble - not dissimilar from the older D7000. If it wasn't for its well known notches, it would be the ultimate closed can. Both are excellent, and I prefer them over other, considerably more expensive closed cans, including e.g. the Sony Z1R (because of its problems or my personal incompatibility) and Audeze XC (ditto).
Between the modded TH900 and D7200, I prefer the D7200 for acoustic, instrumental and some classical, and the TH900 for other genres. If I had to keep only one, I would be in trouble to choose, but the linearity of the D7200 is important to me (having several e-stat rigs at home), so maybe that one. Not a small compliment to a headphone that is much cheaper than the TH900. Maybe the K872 can compete, that too is like double the D7200 price.
In stock versions of similar semi-closed cans, my order of preference: D7200 < Massdrop TX00 < TH900 < Z1R. In modded versions, Massdrop TX00 < Z1R < TH900 ~ D7200. It is my subjective preference, YMMV.
I may try a good e-stat driver (Stax SRX Mk3 or Gamma Pro) in an Onken loaded enclosure like the TH900 (and D7200), perhaps it would be the ultimate (but limited usability) closed can. The D7200 still rules.
Rumor: Sennheiser
might be working on a high end closed can (just as AKG made the K872, the closed version of the 812)... though it is expected to be quite more expensive than the 800S, let alone the D7200/TH900. So the D7200 still rules up to twice or thrice its price range.
