Thanks Peterek ! Finally a thread for Z7 mods. Coming from Sony Headphones Owners, everyone must be fairly familiar with (cups dampening mod). I am gladly reporting in that I have done a couple mods myself, and the Z7 not only show improvements but more like a transformation.
1/ cup chambers dampening mods
2/ upgraded Solid-Silver braided cables toward the drivers
These 2 were the mods that brought in much improvements, and ofcourse the 3rd options of upgraded main cables from Kimber Kables by Sony or whoever you want to call it. I am glad that I also use Solid silver for my main cables as well.
I was able to achieve more sub-bass extensions and energy that give the rumbles effects by the first 2 mods. However the damping mod must be done first prior to the cables being upgraded, otherwise it would be a Pain. The dampening will cancel out the powerful mod-bass resonances which in turn cancel out the sub-bass extensions and mushy out the sub-bass to bass texture or body. This is the main reason why stock Z7 has mushy bass, sometime flappy, and even distort....it is the result from all of the long frequency waves resonated and being amplified by the cup chambers. It amplified resonances make the bass mushy and blur the lines of sub-bass, and the mid-bass slams on the Z7 is very very powerful, that is why the cup need dampening.
Too much dampening material and it loses the volumetric inside to produce proper sub-bass extensions.....blocking out the vent ports and it would also do so. The best is porous paper tape (surgical grade for non absorbent property). That is to avoid trapping and absorbing the humidity in the air which degrades the tapes over the years.
Dampening onto the back would clean up the graininess from within the trebles and create further air and warmth, which in turn also help out to tone the mid-bass and sub-bass body into a much more defined and layered bass, and giving more airs into the vocal trebles region.
Solid silver cables was used to upgrade the super-slim oxygen free copper by stock Z7, which brought into much more conductivity, flows to help the drivers respond faster, in which it helps define more resolutions across the whole spectrums bass-mid-trebles. Most specially would be the soundstage and the bass to be even more controlled and tighter together with the "metallic tints" being more organic and "crystalline" but no longer metallic.
These mods were done, and transformed Z7 into a somewhat unique sound signature with bass that rumbles and sub-bass that pressurize the ears (feel the air) and yet defined mid. If one is picky enough and want even more splash and trebles extensions....the center felt paper could be taken out, thinned out, and that even help trebles further...I don't...advise to take it out.
Never the less, Z7 is a good headphones at it price point, but the potentials to turn it into something even more high-end is there, and can clearly be achieved by what I had done. I can see why some used Z7 can be had for cheap now (I meant cheap). It is the best time to buy them and mod them. You will have the experiences that can hardly brought by anything else...I do mean it, my Th900 is also upgraded but Z7 stands toes to toes with it with just different sound signature.
Any questions, feel free to pm me.
. Now to think about it...taking a Z7 at 2.5x cheaper than th900, and with the same mods....they stand toes to toes with different sound signature....is that such a good value on the Z7 ? I say heck yeah !
neither will have those much open soundstage as the open back. You have a thx00 do you ? The thing is that in balanced mode, they both open up more than in stock SE connection. The next thing I like from Z7 is that while it does leak sound in/out, it doesn't really leak as much as fostex 
