Rick, I've already contacted the customer service and sent the headphones back for repair earlier today. Thank you for your reply, much appreciated!

I've had couple of HF-5's, one ER-6 many years ago and most recently ER-4S. I upraged those to ER-4XR, received those yesterday only to find the right channel is mute right out of the box. Tried to swap the drivers, both work on the left channel so now I'm with a faulty cable. Those headphones...