Probably not a coincidence. Plug the cable back in, reboot the receiver, and try again. If you have already canceled your service, there is really nothing to complain about.
If you had sound before I would suspect the HDMI switch.
Also, if your HT receiver has multiple component & digital sound inputs, I would use this and run component out to the TV.
JimD,
YES, I noticed it too. Sounded like a motorcycle nearby in the woods, although I found it hard to believe they kept filming with the noise present.