In fact, it's not so much the diameter as the thickness of the padding on the ear. It is indeed too small and after a while you feel discomfort or pressure on your ears. I have somehow come to terms with this: take the headset off your head now and then and everything is OK again. The quality of the sound and the incredibly good microphone outweigh this. I won't give the headset away again, especially because of the mute button on the microphone.