Hello,
I just want you to know that I have the same issue with my new Intel Core i5 4670 and my television LG 32LH2000. When the system has freshly booted everything works like a charm. But when I turn off the TV and then turn it on, there is a sound like when new device is connected and then I lose my HDMI Audio device. Nothing helps, I have to reboot the whole computer.
CPU: Intel Core i5 4670 3.4GHz
Mainboard: Gigabyte H87N-WIFI
OS: Windows 7 Professional x64 with Service Pack 1
Graphics Drivers version: 10.18.10.3345
Display Audio version: 6.16.0.3123