Audio Feedback with Sony MDR-10RNC

This may not be classed as a bug, but there is significant noisy feedback when using this type of headphone with the REALTIME option on in the editor (when it is off there is no problem).

Headset used : Sony Noise Cancelling Headphones Model MDR-10RNC
Clicking out of UE4 has silent performance.
Clicking into UE4 produces considerable hiss and buzz in the headset, tied to clicking the mouse.
Pressing Ctrl+R toggles Realtime, and the feedback toggles too (except noise while moving the camera with mouse held down, which doesn’t go away).

Well, plugging the headset into the back audio jack on the PC instead of the front jack eliminated the problem there.