Other than a few mentions on Twitter, I haven't heard read anything about this...so I'm wondering if it's just me. Anyway, ever since about mid-August I have heard what sounds like an electronic ringing or buzzing in the background of some channels. The sound is definitely repetitive, meaning that it's the same sound over and over again. I can hear it the loudest during NFL broadcasts on Fox and CBS as well as on other 'live' events (such as the MTV VMAs, the Emmy's). Can else hear this? I can on two receivers (24-100 and 23-X00) running firmware version 0x4D1. Coincidentally, I didn't notice this ringing UNTIL this upgrade when watching the Steelers-Eagles preseason game on Fox on August 18. Firmware was released the 17th; I forced a new firmware download on both receivers but the sound is still there. I called DirecTV technical support and they had no idea what I was talking about; they wanted to replace both of my receivers but instead are at least sending a tech out to replace a multiplexer. Any ideas?