Update - I tried my headphones with my iPad and had the same problem as my music PC so it is not the PC. I noticed when I jiggled the headphone end of the Jack the problem disappeared. This is what I have suspected from the beginning. I actually had my headphones and associated cable replaced, and had the same problem.. I think it is a design issue in the headphones. Since the headphone cable has a microphone built in the cable, I thought that might be the issue because the Jack for my audio I/O (Line 6 UX1) probably dos not utilize this. I normally plug my headphones into the UX1.
My PC is capable of Bluetooth and my headphones are also wireless Bluetooth capable.
When I look for audio devices in my PC it lists the Line 6 UX 1 as my sound card. Since UX1 is plugged into my PC via usb, now I am wondering if my playback will be routed through the UX1 sound card and delivered wirelessly to my headphones. That would eliminate the cable issue. Gonna give it a try.....