i have an LG ULTRAGEAR monitor but the built in speakers are not working

That's normal. I have had the exact same problem and this is because there's no speakers, only an headphone output behind the screen.

That's why you have a headphone logo instead of speaker logo when you push the screen button to the right.

Audio signal is coming from your HDMI/USB/DisplayPort, but only for the headphone connector.

Yes, there's holes below that looks like speakers holes, but not. It's for thermal dissipation only.

I looked for this issue for several days and finally someone from LG answered me that most of recent LG "gamers" monitors don't have speakers. this explains that.

So yes you have the "LG HDR" in your speaker icon (on win taskbar), yes you do have the volume and all, but ONLY because there's an 3.5 Jack out on your screen.

i looked at the model number on the back of the monitor and put it into the lg website, even though my pc recognises it as an audio device and attempts to play audio through it it does not have any speakers built in

I too have LG ultragear Gaming monitor model 27GN800 QHD ips 144 hz Nvidia Gsync compatible. No built-in speaks ,only I can connect headphones gets sound only when HDMI is connected.

Wow, thank you for this. I just got this monitor and when I connected it it popped up with audio settings etc, and my pc recognizes it as an audio device but I couldn't get sound out of it. I've watched youtube videos, gone through all the settings, and now, 4 hours later - found your post. I have a slightly different model, the LG FHD with FreeSync( 24MR400) but entered in the model and sure enough - no sound. /facepalm
I usually use headphones anyhow but sometimes im watching something and want to show my partner and having available sound is convenient.

Having same issue did you ever find a fix ?