I had a problem with one side going soft on my Super.fi Pros and I eventually tracked the problem down. I noticed if I squeezed the earpiece that kept getting faint, it would come back full force. Closer inspection of the unit revealed that the side that was fading in and out had somehow had that little emlem thingie placed just a little bit off center. I got a pair of sharp tweezers out and worked the emblem back to where it fit just right in the outer casing hole that it was designed to occupy. After doing this, I have had no more troubles with that side. Apparently, having that little emblem just a bit off center put enough pressure on one of the driver units to cause it to not perform correctly. So, anyway, this may or may not be your problem, but before you RMA them, have a look.