I just used my laptop to connect to a tv via a 3.5mm to RCA cable, then later plugged my headphones into my laptop to watch a video and discovered that I could hear the instrumental parts of tracks, but not the voiceover/vocals. Checked the headphones with a different device, no problem, checked another pair of headphones with my laptop, same issue. It seems my speakers have got confused and are now trying to output sound in a different format, but I can't figure out to stop this. If I play sound through the laptop speakers then that seemed to be playing fine, but if I plug headphones in I get this issue. Both headphones are playing exactly the same thing, if I look up a left/right headphone test video, I hear both the left and right from both earpieces. I'm on windows 8 if that's relevant. Any help is greatly appreciated!