I opened my ED9 right side backplate/grill (it is easy to remove and will go back easily and firmly). No change in sound. Basically...
* it is "fully open" design. That`s why it has so good soundstage and airiness.
I can see through the driver when looked against light from one end when nozzle and backplate are removed.
* it is possible to change cable.
Will wait for my ATE first but I already see myself modifing these some day in future (cutting off my ANV modifying plans)
Actually this IEM build is strange... covering backplates wholly doesn`t seem to change sound also. I even did simple test and put tape over backplates leaving no gaps. Maybe... maybe bass got
just a fraction tighter and less "boomy" but change is basically
0. Soundstage doesn`t seem to be affected at all.
So... whatever happens after the driver towards backplates doesn`t affect sound and can be modified, imo.
For example this would be nice and easy mod for those who want to make R/L look different, selfmade different backplates for example. Wooden ones would be very nice
Edit:
Oh! I forgot there`s a little hole by the side of cable entrance! That`s why there were basically no change in sound!
Edit:
Ok, second try - put tape over those holes also... I think bass and kicks got fraction tighter but difference again basically 0.
If someone else bothers to try, then feedback about it is welcome.