dr dre earbud headphone defects

I am on my second set of Dr Dre earphones (in-ear urbeats2) in less than 6 months. I am experiencing the same problem with this set as the first one. One side (left) is receiving a sound signal that is significantly diminished from the right side. I took the first set back to Apple and they made an exchange. Now this new set--in less than 6 weeks--is experiencing the same problem. I only use them carefully while walking on the treadmill.

Based on probability statistics, this error should not be reoccurring to one user twice in six months. Based on my experience, there must be many more users out there with the same issues.