[SOLVED] Need help diagnosing mysterious sound ?

[Kirbyarm]

The sound has been happening and getting increasingly worse since the big west coast heat wave in the summer of 2021. I feel like I can't describe what kind of sound it is accurately. I've tried sampling dozens and dozens of computer sounds from youtube over the months, especially the last 24 hours and not one of them sounded like this.

It's like an up/down roller coaster sound pattern that goes whew whew like a very quiet extremely low pitch police siren. It revs up during activity like opening other windows or applications and is noticeably (but not necessarily 'significantly') louder and more common while gaming. It pulsates the sound where if it were repeating every second, the audible part of the noise loop is about 0.4-0.5s. The speed of the sound can pulse up quite quickly, to 2-4 times per second and go as slow as once every couple of seconds per loop.

I do believe I have tried gently stopping each fan in the tower and listening for it to stop with about a 90% certainty (if not more) that it's not a fan producing the noise, though I did not test the PSU fan. I've disabled all the C states and intel speed shift technology in the bios. Running a bit of a torture test on prime95 doesn't seems to have any drastic significance in the sound, just audible full RPM fans as one would expect.

It's beginning to drive me completely mental here and if I can't figure out the cause and get the problem fixed or replaced, I may be looking at getting an entire new system which I just really can't afford to do right now.

I have recorded a fairly low quality sound clip from just behind the tower in front of the I/O ports by the fan to try and pick up the sound. It's my only means of recording sound and it's not very easy to separate from the other sounds in the clip but you'll hear static, some clicking noise (that I don't hear with my ears, only through this clip), a fan blowing noise in the latter part of the clip but constantly throughout you should also hear the whew-ing noise pulsating amongst everything. I'm fairly certain the sound is coming from the CPU region of the tower layout.

Here is the sound clip. Apologies for the quality.

Specs:
-Intel Core i9-9900K @ 3.60Ghz (not overclocked as far as I know)
-Gigabyte Z390 AORUS Pro Wifi-CF (Motherboard)
-nVidia GeForce GTX 1080 Ti (11GB VRAM)
-2x 16 GB Dual Kit RAM (Corsair Vengeance - Low Profile)
-650W SeaSonic Focus 80+ Gold Certified PSU

Please, someone, anyone, help me figure out where this is coming from! I'm desperate here

 

[drivinfast247]

It sounds like an electrical component is resonating at a certain frequency. Much like a coil whine.

Hmmmmm..... try unplugging all fans except CPU fan and listen if noise is gone.

 

[Kirbyarm]

I managed to unplug sys fan 2 and 3 which stops the front fans but the rear and top case fans are plugged into sys fan 1 which would take removing the entire CPU Cooler to be able to fit my hand in there and unplug/replug it for this test. The issue with this is I don't have spare thermal paste on hand to re-seat the cooler after I would otherwise remove it.

Would the test still be adequate to perform if I stop the 2 remaining case fans with my fingers and listen for the noise while it is happening?

 

[Kirbyarm]

I took a picture to try and show the layout. Here is the picture.

I can barely reach it with the tips of my fingers, and with a few minutes of effort I can probably just barely unplug it by force, but plugging it back it, the amount of coordination and strength required to get it in the socket at the exact orientation I just don't have the room to work with to get that leverage without removing the cooler.

 

[Kirbyarm]

Well the above tests I tried but if there was a, I guess we'll call it coil whine, it was very very quiet, including when I stopped the remaining two with my fingers. I opened 10 video of youtube in sync, some streams a discord video call and a high performance requiring game all at once to try and get it under load, but the whine of course likes to hide when I'm trying to isolate and diagnose it. It's like it creeps up the longer the PC is on, after several hours or ever days. It's definitely still happening while none of the case fans are in motion if that's any further help to the investigation.

Man, I feel so helpless and under-equipped that I can't even unplug a fan properly for a test.

 

[drivinfast247]

Well the above tests I tried but if there was a, I guess we'll call it coil whine, it was very very quiet, including when I stopped the remaining two with my fingers. I opened 10 video of youtube in sync, some streams a discord video call and a high performance requiring game all at once to try and get it under load, but the whine of course likes to hide when I'm trying to isolate and diagnose it. It's like it creeps up the longer the PC is on, after several hours or ever days. It's definitely still happening while none of the case fans are in motion if that's any further help to the investigation.

Man, I feel so helpless and under-equipped that I can't even unplug a fan properly for a test.

If the sound is a CPU VRM making noise there's not much that can be done besides replacing the motherboard.

 

[Kirbyarm]

Oof. If it really is that, it might have to be done soon. We'll see how much longer I can tolerate it for. Thank you.