Answer to: The left ear is not giving audioPossibly this is a wire that has been snapped or disconnected under speaker membrane. Very bad design. I had the same problem (although on the right ear). If you remove the ear pad and the padding, you will see the membrane. No need for any tool to do this. Apply soft pressure with a non metallic non piercing tip on the upper portion and you should hear it play. I squeezed in a piece of paper to have the membrane apply pressure on the wire and bingo. I'm not sure though how long it will last. If it start failing again I will unscrew the piece and look for a more permanent fixture. If you search on Google, you will find a Youtube video (in Spanish with English subtitles) showing you how do it. The guy did it on QC15 earpiece but the same applies on QC25, the wire is just in a different location. Hope this help.