Need an oracle for this problem

[kanash_ningen]

My motherboard has been making a droning noise through the little speaker that is attached to the "SPEAKER" header. It has happened---until now---after the PC has been turned on for an undetermined amount of time.
The PC starts up fine, in fact, the speaker beeps once as it should at POST. There are no warnings set to go off in the BIOS with regards to temperature. The temperatures are fine. The PSU is also more than enough.

I'm a total loss, it only goes away when I turn off the PC. To reiterate, the PC seems to work fine and I double checked that RAM and GPU are seated properly. (However, on one occasion the droning noise still happened even after I turned my PC off and on again. I had to open my case and reseat the speaker. I also discovered that the speaker has quite a lot of play, and can actually disconnect itself. Still, if it's a physical issue, why does it go away when I restart my PC?)
My motherboard is a Gigabyte H170-N Wifi.

[shadowsports]

Someone else reported something "like" what you described, but you'd have to search to find the thread.  "Droaning" to you might be something completely different to someone else.  Is it high pitched? Could it be coil whine?

My crystal ball is on the fritz this week.  How about a vid of said sound?

[kanash_ningen]

https://www.youtube.com/watch?v=9AjFYnKTdnw

This video is the same noise I get. I should have shot a video, but that's basically it. I turned off my PC and back on again, it's nowhere to be heard. It's very sporadic, but when it happens it doesn't go away.

To clarify, I've checked that the noise is indeed the speaker and not a fan or what-have-you.

[shadowsports]

Sounds like coil whine.  The system does not necessarily have to be under load for the behavior to occur, but sometimes opening a game causes it.  Conversely, it can happen when the system is idling at the desktop too.

Power off and disconnect the speaker.  I'll bet it still happens but might not be as pronounced.  Take the side of your case off to help isolate.

Please provide your system specs.  If you have another GPU and/or PSU to test with that would be helpful.   

[kanash_ningen]

Thank you for the help by the way!

So I actually did open my case while my PC was on when this happened 2 days ago. I covered the speaker with my finger and confirmed that's where the noise was coming from. I removed the speaker and there was no more noise. I noticed this is the solution you've hinted at with your last reply: remove the speaker. It would be a shame if I had to resort to that! I'm mostly worried that the speaker noise might mean something is wrong, but that seems unlikely at this point.

My specs: H170-N Wifi
               i5 6500
               GTX 1060 (Overclocked)
               8 GB DDR4 Single Ram
               Corsair RM750i
               Cooler Master 130 Case

So my PSU is overkill for my build. I doubt it's causing any problems. I unfortunately have no spare components to check what the problem may be---that said, considering the computer boots up fine with a single POST beep ("OK"), it doesn't make sense that a faulty component would be detected by the motherboard sending a buzzing noise in the Window's environment? The buzzing noise, like you said, might be coil whine? I wonder what the motherboard is doing to the speaker??

*In the Youtube video I posted, I noticed that author seems to think it's related to his GPU? I don't know if that's true, but he ultimately removed the speaker from the header.

[shadowsports]

The noise is actually mechanical in origin...  its caused by vibration.  The speaker can augment it.  Take a close look at your build.  You don't want to torque or over-tighten anything.  What kind of speakers are you using?  This is almost impossible to get rid of without changing things out.     

[kanash_ningen]

I guess I'll have to take a look at how the motherboard is seated, short of just pulling the darn little speaker out.

Thanks for the help.

[shadowsports]

This..  and ensure your CPU heatsink is properly installed, video card too.