According to MacRumors, a number of iPhone Plus owners have some trouble with their phones, or at least their headsets. They say that, when using headsets during the call, they can hear a loud-pitched, annoying static sound coming from the headset’s earpiece. This issue did not occur when using headphones or phone’s own speaker. It is said it does not matter whether you are using 4G voice or WiFi calling, if you have noice cancelling enabled or if you are using a VoIP app. Performing a hard reset is said to sometimes help, but not always. Apple support team advises those with the above issue to restore their phone to factory settings. They said that, of course, they are working on the issue.