This Sennheiser HD400s only has audio coming out from the R speaker. There is totally no audio from the L speaker. Some testings are done to find out the exact problem.
I found it in speaker shops that sells a lot of parts for you to build your own speaker. Not all of them sell this specific cable, but eventually I found one shop that sells it.
I forgot to press the record button when I fixed it. So I don't have any video clip for it. But the fix is basically replacing the cable connecting the left and the right speakers. You can only get access to that cable once you completely tearing it apart. ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-9I1khD_dTBs.html
