AirPods poor call quality (for receiver)

[Barnfather]

Girlfriend recently bought a pair of AirPods. Tried them out with my phone and thought the music quality was awesome, and decided to perhaps get a pair myself this weekend.

Only problem is she has called me several times using them, and the sound quality is abysmal compared to her old EarPods, and certainly far worse than talking into the phone. Her voice is a little muffled, there is a white noise hiss in the background and whilst I can understand about 80% of what she says - if I concentrate - I worry if this is the quality of the things for making calls.

Looking on the web everyone raves about sound quality, so I'm not sure what the issue could be.

Any ideas? Call quality is perfect on her end. She blames the mic being so far from her mouth, but I doubt that is the problem. Is there any other part of the earpiece that has any mic/sensor on it that could be being blocked by something (hair?). Or is it just a case of taking it to Apple to look at?

Edit: She is using them paired to her iPhone X, if that matters

 

[cynics]

Do a quick reset to the phone. Make sure they are firm in her ear and pointing down toward her mouth. Make sure they are on the latest firmware (open them next to the phone and goto settings > general > about > AirPods (should be 3.7.2). Forget them in bluetooth settings and repair them.

If nothing works warranty replace them. While they dont sound like being on the phone the call quality in my experience is very good. I've never had anyone even hint at them not being able to hear me properly.