I was listening to my SM3 and somehow I noticed that the bass was coming stronger on my right side. Hmm, it must be something wrong with the earphone, I thought. So I cleaned the left noozle, adjusted the tips and still same problem. So I tried my cx300 and long behold same problem. So I switch sides and changed MP3 player, put just the right earphone on my right ear and then put it on my left ear. Then I put just the left earphone on my right ear and then put it on my left ear. The conclusion, I can hear bass on my right ear, but I can't on my left ear.
I don't listen to very loud levels, but I do listen all the time at work. I also have a mild titunus on my left ear. So I am loosing my hearing, so sad!