My Phonak's grey filters are now apparently our of production (according to my local Jaben guy), so the next best thing that I can use would be my ER-4PT.
However, as universally known, the ER-4 series may be very... strict with music. Are there any upgrade (or in this case downgrade) cables that can replace the stock ones? I'm new to upgrade cables, so I'm not sure whether those used in customs like JH Audio are the same. I do know, however, that the UE/Shure ones are different, and I know I can't use those.