So not to long ago I posted saying that my westone 4 sounded muffled on my iphone. Even with the Fiio E5 it sounded like music was playing through a blanket. The only difference is that with the Fiio E5 it was a little louder.
However after testing them out for some time now, it seems like this problem only happens when I'm on the iphone or fiio E5. On the computer or stereo the muffle is gone. It's clear as day even at super low volumes. I'm only guessing and but is it possible that the westone 4 needs more power? But if that was the case the Fiio should have been good enough for them. I can't image the westone needs more than the Fiio E5 to sound good.