I grant that this could be the issue of the TV, but it could also be an issue with drivers etc, so I'm hoping to get a troubleshooting process going.

Issue : When a program or task is started which contains audio, the screen flashes black for a split second (coming back fine), and audio engages a second later.

The same sometimes occurs when Audio disengaged.

For example : If I open a youtube video, the screen will flash black for half a second, and the audio will engage one second into the video. There are no further issues provided the video remains open. The same occurs when playing video files, or even with audio notifications such as with chat programs (in which case the first notification is missed, but subsequent sounds play fine.)

As far as I can gather, it seems to me like the video output disengages momentarily while the audio can be patched through the HDMI output of the video card. I could of course be wrong.

My first instinct is to assume that audio is disengaged when not in use, and given that it's fed through the HDMI port, that the video drivers have to re-start (or something similar) to combine the audio.
Hence, my hope is that it's a simple matter of finding a way to tell the audio not to disengage when not in use, or to tell the video driver to always have the audio patched.

Heck, I'm a total rookie in these matters, I'm used to troubleshooting network issues, not audio/video issues. I could be way off base with the cause here.

Which is obviously why I'm turning to you guys.

Setup :
Ubuntu 12.04 64bit (no modifications other than proprietary driver)
All updates installed as of today.
MB : 970A-D3
CUP : X8 Bulldozer
Video Card : AMD Radeon HD 5450
Video Driver : ATI/AMD Proprietary FGLRX graphics driver
Connected to : LG surround sound + LG 47" tv
Via : HDMI