A little audio mystery for the PC specialists...

[Mike Senior]

Hello everyone,

I have a little mystery that's been bugging me for a while, and I can't think of a better bunch of people than SOS audio/PC specialists to solve it!

Here's the deal. For months, I've been getting a strange intermittent noise from my main studio PC. It sounds like this -- I've got so used to it I've nicknamed it the studio chipmunk!

It doesn't happen all the time, but its appearance, and the frequency with which it occurs, seem to be related to the temperature of the computer in some way. What's odd, though, is that it's the kind of sound that it's almost impossible to locate. I've had the side of the computer off while it's happening, and whenever I think I know where it might be coming from, and put my ear there, it grows less distinct. I just can't seem to trace where it's coming from. It's really weird. (Maybe it's all just in my head. I've not yet heard it when the computer's off, though, which is somewhat reassuring...)

In conjunction with this, I've been getting occasional BSOD crashes. Not often enough to cause me any real problems, and not reliably enough that I can really troubleshoot it, but again I suspect that these may be linked to whatever is causing the chipmunk noise, because the chipmunk seems to get progressively more active in the run-up to a BSOD.

So my question is: does anyone here recognise that sound, and have an idea of what I (presumably) need to replace?

[Eddy Deegan]

Do you have conventional HDs as opposed to SSD storage Mike?

I initially thought this could be a fan with a wearing bearing, but I've also heard hard drives make noises a bit like this when they start to get a bit unhappy and the stepper motor/drive head assembly frantically does weird stuff, presumably trying to recover from something it's troubled by.

Just a punt based on the audio but it might be worth checking the S.M.A.R.T. status of your drives if they are conventional HDs. If it is that then data loss is looming so hopefully I'm wrong and/or you have backups!

[John Egan]

Mike,
Could be hard drive, but it sounds to me like a fan.
Regards, John

[Hugh Robjohns]

I'm exactly with Eddy: My first guess would be a drying-up fan bearing, and my second would be a hard drive on the way out. Both are likely to get worse with increased localised heating.

H

[Nazard]

It sounds like a poorly fan to me too. Conjecture: if the fan is plugged into a motherboard header, as the fan stalls the current drawn will increase. Perhaps that could be a factor in the BSOD issues?

[Agharta]

Use software to track the temperature of your CPU/GPU/Drives and the fan speeds and when the noise occurs take a look at them.
Do you have a GPU with a fan?
As well as that it could be the PSU.
Look at the SMART info for your drives.
Only the Boot drive should crash the system I imagine!
Case fans shouldn't matter unless the CPU is highly loaded and overheats due to lack of case fans working.
CPUID HWMonitor should track all you need.
With a BSOD there should be a system dump which can be analysed.

[Mike Senior]

Thanks everyone! I'd kind of suspected it might be a fan, and I'm pretty sure it's not a drive because I replaced my drives a while back when I began getting the BSODs. Thanks for the monitor utility tip too -- I'll check that out. Failing that, I might have to resort to a rodent trap...

Thanks again!

[Agharta]

The sound you recorded also has a hint of coil whine in it.
That tends to come from the VRMs I think on GPUs or CPUs/motherboards.
Some CPUs have the VRMs integrated but most are on the board.

[Pete Kaine]

I don't think it's high-pitched and constant enough to be coil whine. I'd also lean in the direction of a dried up baring catching/dragging.

T.B.H the thing it more reminds me of is a warped DVD scraping in the optical drive.

Easy enough to test this, next time the noise starts just go in and unplug all the fans, starting with the case fans. If that doesn't help, quickly do the CPU cooler fan (it's fine in short bursts... well, as long as you're not kicking the daylights out of the CPU at the same time) and see if any of those fans are the suspects.

After that, if the cooling is fine, start running with a disk drive unhooked each time you start and try and trigger the noise.

One thing I guess it could be that the above doesn't cover is the fan in the PSU as you can hardly unhook it in use.... and the scraping noise, well, it could be in there. I guess you just shove you head next to that when you've unhooked all the other fans to check by that stage.

[Agharta]

I don't think it's high-pitched and constant enough to be coil whine. I'd also lean in the direction of a dried up baring catching/dragging.

The recording is not that great seemingly so I was using my ESP!
Coil whine doesn't have to be constant from my experience.
You can also get whine from the PSU which also has a fan so who knows!

As you said Pete, I'd disconnect as much as you can and boot the PC and leave it at idle to see if it crashes.
You can use software such as Speedfan to lower fan speeds and stop them but this will depend on if your hardware supports such apps:
http://www.almico.com/speedfan.php

That way you don't have to disconnect any fans so it's quicker to troubleshot.
You can lower the CPU fan to the point where it's much quieter or inaudible whilst tracking its temp to keep it within spec.
Difficult to damage one as they will throttle or shutdown automatically in the case of fan failure.

You might want to uninstall Speedfan afterwards in case it impacts latency!

[Martin Walker]

One thing I guess it could be that the above doesn't cover is the fan in the PSU as you can hardly unhook it in use.... and the scraping noise, well, it could be in there. I guess you just shove you head next to that when you've unhooked all the other fans to check by that stage.

I agree with nearly all that's been said above - it sounds exactly like an ailing cooling fan to me, although normally once these starts ticking due to a temperature rise they generally (in my experience anyway) continue to tick along until the fan speed slows right down again.

One possible solution that I've used in an emergency to test out the PSU fan if you suspect that's the culprit is to stick a plastic straw. wooden artist brush handle or similar insulated object through the rear PSU grille between the blades of the fan, to temporarily halt it for a few seconds.

This shouldn't do any damage, but if the chipmunk stops chattering you've found the offender.

Martin

[Pete Kaine]

Coil whine doesn't have to be constant from my experience.

Yes, true, the sound I had in my head was where the VRM's are running hard and it tends to sharply change pitch when power mode switching forces it too. Maybe I was being too specific in the noise I was mentally picturing... or maybe it's just the tinnitus.

One possible solution that I've used in an emergency to test out the PSU fan if you suspect that's the culprit is to stick a plastic straw. wooden artist brush handle or similar insulated object through the rear PSU grille between the blades of the fan, to temporarily halt it for a few seconds.

I tend to find that cable ties if left to their own devices will often tend to naturally migrate towards the PSU fan in much this fashion.

[Mike Senior]

Lots of great extra info everyone -- thanks for the continued advice! I'll do my best to track this thing down as and when it surfaces again, and I'll let you all know when I find the culprit.

[The Korff]

Agreed, it sounds like a fan — either a dodgy bearing, or some cable brushing against it. Dying spinner HDs tend to make more of a 'ticking' noise.

[hobbyist]

Hello everyone,

I have a little mystery that's been bugging me for a while, and I can't think of a better bunch of people than SOS audio/PC specialists to solve it!

Here's the deal. For months, I've been getting a strange intermittent noise from my main studio PC. It sounds like this -- I've got so used to it I've nicknamed it the studio chipmunk!
.................

Sounds too slow and irregular to be a disk problem.

Sounds more like something rotating slower than a fan too.
Could there be something stuck in the fan blades? And it is caught at times and dragged around.

Can you rule out external interference. LIke an airplane tower type radar sweeping slowly outside that somehow is causing the sound you hear.

[Mike Senior]

Well, I think I've eliminated all the fans (four of them in the case) but the PSU's. A bit tricky to access that one, but I'll see what I can do. As for something being caught in the blades, I reckon that' unlikely, because it's been happening for months, and it always happens in roughly the same way as that audio file.

[Agharta]

A dodgy case fan is very rarely going to crash your PC so if the two things are related then that was always an unlikely culprit so that leaves the CPU, PSU and possibly a GPU.
If you have a dGPU and it has a fan you can usually monitor that either with the software I linked to earlier or using the AMD/Nvidia software.
Often you can disconnect the GPU fan with no ill effect if you aren't using it for more than basic 2D work.
Although some DAWs/VSTs are using the GPU in more intensive ways these day for the GUI.

As soon as you hear the noise I’d look at these other fan speeds to see if they are fluctuating. Set the monitoring software you are using to update as quickly as possible. Speedfan can also monitor some GPU fans and will also graph speeds I think! So just keep it running and it will show you any unusual spikes.

[cyrano.mac]

The sound you recorded also has a hint of coil whine in it.

And that points to an aging PSU that could fail any minute and take some other hardware with it...

[Mike Senior]

And that points to an aging PSU that could fail any minute and take some other hardware with it...

Well, it appears that your instincts appear to be correct -- just swapped out the PSU today and haven't heard anything from our friendly chipmunk.

Ahhh... silence is golden...

Thanks again everyone for the advice!

Mike S.

[Eddy Deegan]

And that points to an aging PSU that could fail any minute and take some other hardware with it...

Well, it appears that your instincts appear to be correct -- just swapped out the PSU today and haven't heard anything from our friendly chipmunk.

Sounds like a result! I'm glad to hear the problem seems finally sorted

[Martin Walker]

...and what a fascinating journey it has been for us all!

Bye bye chipmunk.

Martin

[Mike Senior]

Bye bye chipmunk.

He lives on in my heart...

[Hugh Robjohns]

[cyrano.mac]

And that points to an aging PSU that could fail any minute and take some other hardware with it...

Well, it appears that your instincts appear to be correct -- just swapped out the PSU today and haven't heard anything from our friendly chipmunk.

Ahhh... silence is golden...

Thanks again everyone for the advice!

Mike S.

You'd be amazed how many people's computer audio problems originate in old, underpowered or sloppy PSU's...

Sometimes the ground connection is so sloppy the thing has to produce hum. Tightening the screws can sometimes fix it, but some PC PSU's just need to be replaced. It's one thing Apple seems to understand.

[Eddy Deegan]

Nice one Cyrano. I think you nailed it