I'm using the computer (Windows 8.1) with LG 22MP55HQ monitor (HDMI), but something is wrong with the monitor audio output. When I plug my speakers (or headphones) to the blue audio output in the back of the monitor, there's no sound at all. I'm wondering why this audio output socket is blue, usually it should be green. There's only one audio socket in this monitor and according to the manual it should work with HDMI. I've checked the sound level in the monitor menu - it's OK.
Maybe there's some Realtek driver incompatibility, or a special jack is needed?
Excuse my rather bad English, it's not my native language.
Thanks for any reply and support.

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