I'm thinking about bying an used pair of ESP 950s and seriously modding them. I've considered making a totally DIY ESL headphone, but making the headband and enclosures for them is too much for my limited skills. Kosses though seem to be a fine ESL headphone as they are, and from pictures of their insides on Wikiphonia it seems that there are some mods easily possible.
1) Removing damping and maybe adding 'phase corrector' like on old Fostex T50 - a felt ring which suppresses high frequencies coming from outer parts of their drivers to even out phase and frequency responce.
2) Regluing drivers to remove possible squealing.
3) Maybe drilling some vent holes around driver to play with air loading on both directions - if needed. As Kosses are regarded as very tonally level, I suppose it's already alright.
4) Using laser CNC to cut a more open and more stiff stators to replace stock ones. Stocks seem to be not very stiff and having too little open area. Also I don't get the purpose of 'tubes' on their stators' holes. These can be replicated by thicked PC board, I believe.
5) Recabling them using DIY 'Verumecce' cable: http://www.diyaudio.com/forums/analog-line-level/194548-new-interconnect-design.html Additional opposite bias would be required though, but that is not a problem.
So, I'm asking more experienced people here, would these mods provide improvements? Maybe someone already tried something like that? Thanks!
