Among the smaller changes, Sennheiser has made with the HD 820 are new ear pads, which are a mix of synthetic leather and microfiber, created with the express purpose of helping insulate the listener from the outside world. Sennheiser is also adopting the 4.4mm Pentaconn balanced connector. It is a little larger than the traditional 3.5mm audio plug but provides balanced audio for minimal distortion.