Chosen Solution
I have been using an iPhone 4 as my desk phone. I have some Audio-Technica M30 headphones that I use when talking on the phone. The phone sits about 18 inches from my mouth and everything is great. I recently got an iPhone 6 plus to use as my desk phone. Same headphones, same positioning. Terrible sound quality for the people at the other end. I can hear them just fine. Played around a little, it has something to do with the headphones being plugged in. When I’m on speakerphone, or holding the phone up to my ear the sound quality is fine at the other end. It is only when I have the headphones plugged in that my voice gets electronic and choppy and sometimes drops beginnings of words. Any ideas what is happening here? Any suggestions on how to fix it? Update (09/16/2016) Just to clarify, it is the voice quality of the microphone as heard by the person I am talking to that degrades when the headphones are plugged in, not the voice quality I am hearing, what I am hearing is crystal clear.
Get a qtip and get off some off the fuzz. Clean the headphone port with it.
The headphones likely have a built in mic. Try to go on a phone call and tap both mics on the phone (one next to headphone jack, and one next to camera) If they can’t hear either, then you know the headphones have a mic
