Humming...

Amp34

Amp34

Amp34

Caporegime
Joined
25 Jul 2005
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Canada
Random thread of the day (probably)....

So my sister compains about my computer "humming" in her room (next to mine) when she is in bed, which means I can't use my desktop after about 11pm. It's not her making it up either, there is an audiable hum when on the landing too, which is very strange as my PC is actually very quiet (spent a lot of time and *money* to make it quiet), to the point it is almost inaudiable during the day when sat next to it (nexus etc fans and a Lian Li B25 case).

Now the only thing I can think it is is actually vibrations rather than noise as such, which i need to figure out how to remove. The case sits on a plinth that sits on a wooden floor close to the dividing wall, which could be the main reason for the noise.

So to remidy it I was thinking about maybe sitting the PC on top of a 1" foam bed? If I can't remidy the noise I may have to put the components back in my old case (an Antec P150) and see if that makes any difference, as it's heavy Steel, not light Aluminium.

Any other suggestions or thoughts on this problem?
 
Standing it on foam is the obvious approach, but how about going to opposite way.

If you stand it on something very heavy, say a load of cast iron weights, the vibrations from the case will have to move a lot more mass and so will be much less effective.


edit: i agree that it's vibrations that's the issue, probably the floor vibrating and setting up waves in the air in her room. A bit surprised your room doesn't hum as well
 
Good idea, that may be a workable plan, and look nicer to boot.

Just nabbed a photo I took the other day from the show your desk thread to show what I was talking about location wise.

img1588w.jpg


The PC sits on a 1" MDF board, which sits on a 1.5" MDF board (to make the seperate PC and shelves easily removeable).

I am just wondering however if all the very dense material underneath it is one of the reasons for the humming?
 
Mass will change the frequency of the humming. Increase mass, resonant frequency goes down. The idea is to push the resonant frequency down far enough that it's no longer audible.

I've not experimented with putting weight under the case, but I've certainly put effort into making the side panels weigh more for this purpose. Well worth a try if you have said weights lying around, looks like they'd fit quite tidily
 
JonJ678 said:
...
edit: i agree that it's vibrations that's the issue, probably the floor vibrating and setting up waves in the air in her room. A bit surprised your room doesn't hum as well
Click to expand...

I think the reason mine doesn't hum may be because it is drowned out by the noise of my case, the hum really is very low pitched and just audiable in very low noise environments (such as night time), and explains why it can't be heard during the day.

Any suggestions on making the sides weigh more? I love the B25 but it really is light, which "causes" a lot of the noise that the computer makes (and why I think the P150 is a better noise reducing case).

Another thing I just thought about is I don't think I added any rubber grommits to the fan attached to the case, which could also make a difference (at least partly) to the vibrations. As long as it isn't the PSU fan or GFX fan that is the problem that shoud help reduce it majorly...

On the note of Rubber grommits, has anyone used either the Akasa or Acousti ones that OcUK sell, any good?
 
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The Acousti ones are considerably superior and worth using if the rest of the box is quiet, the Akasa no better than screws but a bit more convenient. The fan in my psu is mounted using the acousti pins.

Butyl rubber matting, vinyl floor tiles or flashing tape. My favourite is the flashing tape, have a look partway down here for some photos
 
Acousti will be ordered tomorrow then. :) I didn't think about replacing the PSU fan screws as well.

I'm not too sure about sticking flashing tape to the inside of my case tbh, I know how messy it can be, and don't really want to destroy the inside. Possibly a last resort however. :)
 
I've been experiencing a lot of humming from my pc recently too, first of all i thought it was the fans, i stopped every fan individually to see if the humming would stop.

Turns out it’s the poxy hard drives lol Not sure which one, but it's make an intermittent hum, can't really explain it but it’s like...

Hummm *rattle* humm - *no noise* - *rattle* hummm

:cool: so yeah, it was the hard drives in my case, although I'm not fussed as I'm replacing it all.

But check it's not your hard drives, because no matter how much foam you put under the case, the hard drives will still hum, try to secure them etc.
 
Very true. :)

I used to have my HDD's suspended in the p150, however no such luck in the B25. I was thinking instead of seeing if I can suspend them again, going to have to take a look inside tomorrow I think.

Just ordered the Acousti's so they should arrive tomorrow hopefully (dispatched RM 1st)...
 
Well I got my Acousti things today, and spent an hour trying to fit two fans with them, they are a right pain!

However it doesn't seem to have solved the problem, but I do now know what is causing it, obviously it's the hardest thing to sort...

It's the PSU fan that I assume is giving up the ghost slightly, and is impossible to attach with the Acousti things. So my only option is to replace it and possibly leave the grill off and use some double sided padded tape, not an ideal solution however...
 
sitting your case on wood will act like a woofer speaker with the vibrations. you'll need foam or rubber matting; or to suspend your pc in mid air using 1000's of elastic bands...which i'd really like to see a picture of if you manage it.
 
Elastic bands fail with temperature variations.

The fan pins are easy once youv got the hang of them. I broke a couple learning though, push them through a bit, then pull from the otherside until the triangle comes through, relax, then pull again to get it into final position. Feed the fan onto all four at once, then pull through opposite corners at once with needle pliers.

You sure you cant mount the psu fan using them? Ive done so with mine, though I did have to take the casing off to achieve it. Hard drive vibrations seem likely to be the current problem, which pretty much means suspending them or stopping using them I'm afraid.

How goes standing it on heavy things?
 
Elastic band PC? :D

However as JonJ says elastic bands are liable to break, I had a set of bands for using in my P150 (provided with the case) and they broke after about a month..

I managed it in the end, it was just the opposite side of the fans where I had the problem, I couldn't reach them, even with a pair of long nose pliers or tweezers. I managed to get them in the end however, by seemingly taking apart most of the PC...

Having thought about it after writing the last post I think they would actually fit (I thought the holes in the PSU were too big, however they probably aren't), i'm just a bit nervous about running a PSU without a fan guard. I think i'm going to replace the fan in it first however as it is humming up and down, so there is something wrong with it.

As for the HDD's I don't think they are actually the problem, it all seems to be down to the PSU fan, so although I'm thinking about suspending the cage i'll leave that until i've checked whether changing the PSU fan will suffice.

Haven't sat it on anything heavy yet, that's again on my to do list. :D
 
I seem to take the entire case apart to move minor things about fairly often. I think its just that I like taking it apart really.

I've got a solution for the fan guard issue. Pin the fan to the inside of the psu using two mountign pins at opposite corners. And pin the guard to the outside of the psu using the opposite two corners. Pines pointing outwards rather than inwards. Its easiest if you put all four pins in, two facing the other way, then the internal fan, then the fan guard. You end up with a couple of spikes facing out from the fan guard, but if you look at the pins you'll see that you've got the fan softmounted on all corners after all. Softmounted grill doesn't matter, except in that it avoids hardmounting it to the fan.

I think you'll solve the psu fan, and then notice the hard drives. Then solve them, and notice...?

I'm at the happy point where all I have to worry about is a psu fan, the only case fan is a s-flex running at 7V between two radiators and about as quiet as a fan can ever get with that much mass either side. The psu fan is giving me trouble though, and when I solve it I'll have to cope with the ddc being too loud
 
You can get silicon/rubber gaskit type things to put between the psu and the back of the case to cut down on the vibrations being transferred. Perhaps this might be worth a try. As if you PSU is under warrenty opening it to change the fan will void it.
 
Ahh, I think i've seen a photo of that actually, have you posted one up on OcUK? I've just ordered another set for the PSU, and if it's still annoying me after mounting it like that, replace it. :)

Quieting your PC is a never ending battle, I've spent so long changing fans, cases and fan speeds to get the right combination I'm at the point where there are only two issues now (other than possibly the HDD's, after changing my case), the PSU fan, and what always used to be the loudest component in my system, the GFX fan (fitted with an aftermarket fan at 5v), unfortunately unless I go passive with that (using a 6800GT atm) there is no way of making it quieter. :)

At the moment I have two case fans running, one 120mm at the front and the other 120mm at the back (both 5v'd), as well as a 120mm (manually set to min) on my CPU cooler. All are a selection of high quality quiet fans, which I've never been able to hear over the GPU fan.

mogwai, i don't think that would help me in my situation as the PSU only touches the sides of my case, and there is no space between the PSU and case to fit anything in. :)
 
Yeah, that was me. Photos partway down here, couldn't get the forth pin in whole annoyingly but it worked well anyway. I don't have a photo of it combined with shroud and fan grill I'm afraid, will take one for you if you're interested. I attached a 80mm shroud to the outside of the psu, with the finger guard on that. Directs sound away from me and slightly cuts down on noise by reducing the static pressure the fan's pushing against. i quite want to put an 80mm radiator there but I don't think its wise.

Graphics caused me problems too, eventually gave up and put a waterblock on it. The thermalright cooler on it before was massive, but did work passively.

Sounds like you're close to the point where mass loading and acoustic foam is the next step, congratulations :)
 
Right, update:

Gromited the PSU fan and no difference, so I decided as a few said on here that it must be the HDD's, so I made some silicone feet (using sealant) and tried again. Lo and behold the humming had gone and the machine was very silent. However I couldn't get any signal to the monitor...

After a week of non use I managed to go out and get a DVI-VGA adaptor thinking I may have broken the old one, nothing happened, so I swapped the PSU cables around in the PSU (modular) and signal worked (I fiddled with some other stuff as well so maybe...).

Anyway after using it for a day I realised my newest 500GB Hitachi HDD was missing, with all my media on... So out comes the PC AGAIN and I find the power cable has been knocked out, plug it back in and turn on again, humming starts again, with vibration of the case going from practically nothing to noticeable..

I've just unplugged the power cable again and the humming has gone again, so it's obviously just that HDD that is causing the problem. Which to me indicates maybe a dud HDD? It still seems to work and there is no *click of death* however none of my other (older) Hitachis' hum up and down.

RMA? It's only about a year old.
 
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