# Hearing a noise from PC



## ghost rider (Dec 29, 2010)

Yesterday I became aware of a low frequency noise. It was very subtle and hardly noticeable. This is in my equipment room. I can’t say I ever noticed it before. The strange thing is it was completely in auditable when I am sitting at the computer when I stand up I could plainly hear it. It’s kind of like a ground loop but has a lower frequency.

It took me while to isolate it. Thought it might be the furnace running or the refrigerator in the kitchen. I turned on and off the PC. That through me off because it didn’t come on when I first turned on the PC and would keep running after I turned off the computer. I put my ear to the PC and cycled it on and back off perhaps 5 seconds after it on the HD would spin up[ and after I shut it down it would keep spinning for at least 5 second. I figure it ran till all the power had drained from the power supply.

At first I thought it was interesting how the sound was in auditable at 40 inches from floor but plain at 60 inches. Then I started thinking this may be the first sign that a drive is going bad. So I posted a thread to get some thoughts.


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## Harpmaker (Oct 28, 2007)

Sounds like this can mean the drive is beginning to have problems, or it could simply be a sound that has always been there and you just never noticed it before. Once you do notice something like this there is no way you can pretend not to hear it. It's like noticing a scratch on a TV or monitor; after you see it your eye will always be drawn to it.

Hard drives are mechanical devices and as such it's only a matter of time before they fail, never a matter of IF they will fail. ALWAYS have important data backed up to at least one other source, and preferably more than one. If you don't you WILL eventually lose that data. I think we have pretty much all "been there, done that".


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## nholmes1 (Oct 7, 2010)

Also check all the fans in the unit, when the ball bearings burn out they produce a similar sound.

But the hard drive would be the first place I would look.


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## Zeitgeist (Apr 4, 2009)

I'd disconnect the hard drive, see what happens.

Honestly.... I've never heard a low frequency noise from a hard drive. Normally when the bearings start to fail, it's a nasty high pitch whine. Although, I've heard some odd vibrations from the hard drive causing the case to resonate... But the drive itself was quiet.

I'd be more inclined to suspect a fan. Especially a mainboard or CPU fan - since they tend to be smaller and more likely to clog and act up.


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## ghost rider (Dec 29, 2010)

In reply to the last 2 responses, I originally thought it must be a fan but what was weird and made it interesting is how I could hear the fans turn on and off instantly as turn it on and off. The noise was delayed 5 to 10 seconds both turning it on and off.

When I put my ear up to the case I hear the drive spin up seconds after I power it on and continues after I turn it off 5 to 10 seconds.

I plan to open it up and isolate the exact sound and if it’s a drive I will made sure its backed up.


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## nova (Apr 30, 2006)

I agree with the others. Typically a HD does not emit low frequency noises, fans with bearing issues do.
Your 5-10 sec delay also makes me suspect that a fan is the culprit. When you start your PC the CPU is room temp, most computers control CPU fans by temperature so the CPU fan will not usually ramp up to full speed until told to do so. Depending on your computer and how its set-up most fans (CPU, GPU, North Bridge, case, PSU) are temperature controlled by the BIOS or some other program (Q-fan, Core Center, Easy Tune,Speed Fan etc.), thermistor, linear voltage regulation, pulse-width modulation and on and on and on.


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## iconrl (Jul 30, 2010)

Did you check for any critters in the computer??









Haha, Just kidding of course.


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## ghost rider (Dec 29, 2010)

LOL I should check.

I'm not to worried mostly I thought it was very wierd how the frequency just hangs there in a specific part of the room. Besides worst case I have to reprocvess about 16 BD movies.


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## peterselby7 (Nov 29, 2008)

could be dust on a fan... I've had that send cooling fans off balance and cause vibrations.


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## BoredSysAdmin (Mar 6, 2011)

Like what other said - clean the dust of the fans first, possibly you need to replace them is cleaning doesn't solve the issue. You can stop each fan individually to troubleshoot which one is noisy.


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## ghost rider (Dec 29, 2010)

Thanks for all the suggestions. I haven't opened it up yet. I don't think this noise is a fan because of how I can hear it spin up and spin down a few secounds after I turn it on and off.

All the fans are instintly on and instintly off when I power on and off. That's what made me take a close look. After powering it off I still hear the low frequency noise for a few seconds. So I started looking around trying to figure out where it was coming from.


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## sparky77 (Feb 22, 2008)

Just a crazy guess, but I would say the power supply fan is dirty. I kept hearing a strange rumbling noise in my bedroom all the time, and it turned out to be the power supply fan on a computer in the basement was really dirty and out of balance. It seemed strange to me at first how the fan could "throw it's voice" so much as to not hear it sitting right by the computer. Could be interesting to hear the final outcome on this one.


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