Is anyone having this problem with their iPhone 5? During a phone call using the new earphones, the volume drops off occasionally so that you can barely hear the other person. The volume seems to go up and down so that you miss a few words here and there. I wonder if it has something to do with noise suppression by the external microphone? Note 1: the earphones work perfectly when listening to music--the problem only occurs during phone calls. Note 2: when talking to the same person from the same location and removing the earphones, there is no problem hearing the other person.