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Need help to silence case fans

Discussion in 'Desktop & Laptop Computers Forum' started by Pbryanw, Feb 17, 2005.

  1. Pbryanw

    Pbryanw
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    As my computer runs a bit hot I decided to purchase some case fans. I bought some cheap ones off ebay but they didn't provide the necessary airflow so I turned to Quietpc and bought some Acoustifans. The airflow's a lot better but they make a high pitched whining noise which they shouldn't. The cause for this noise is the holes in my case which the air flows through. If I put my hand over the holes the noise stops, so it's not the fans spining that's causing it.

    Anyway I just wondered if anyone can provide a, preferably easy, solution to this case grill problem:lease: so I can go back to having a quiet pc.
     
  2. jameson_uk

    jameson_uk
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    The accepted solution is to cut out the grill. This is normally quite easy as they are only attached in about four places. The only other way I have seen anyone suggest is to create a baffle (?) which is basically like a hood over the output to direct the airflow down

    |_
    x \
    |

    This is my really bad sketch where x is the fan and the bits in blue are the baffle (you can make one out of cardboard or something like that.

    I did try it once but found cutting out the grill completely was the only way to really get rid of the noise.
     
  3. groovyclam

    groovyclam
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    Just unscrew and/or hacksaw off the grill of the case.
     
  4. KraGorn

    KraGorn
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    That's not necessarily true. If these holes you're referring to are the only way air escapes from the fan then putting your hand over them will slow down the airflow, and thus slow down the fan.

    The only way to be sure it's not the fan is run it in free-air, I've known AcoustiFans to make a pitched noise (ie. not just a 'whoosh'), unless you need massive air-flow then something like a Fan Mate 1 is the answer to control the fan's speed.
     
  5. Pbryanw

    Pbryanw
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    I thought that cutting out the grill might be the only solution :( but I'll give it a go. I assume I'll need pliers or something to cut the grill out:confused: As for the high pitched 'whine' I've since discovered (by running it free-air as KraGorn suggested) that the fan rotating is making some of the noise so it must be the bearings, electronics, air flow or something. I'm a bit disappointed as the Acoustifans are meant to be near silent.

    Anyway I've decided to buy a SilenX 14db fan to compare with the Acoustifan. If the worse comes to worse I'll just take the casing off the machine and air cool the damn thing.
     
  6. KraGorn

    KraGorn
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    Silenx are very good, especially the larger, slower ones, but even they can make a low buzzing sound I've found .. I have 2 x 60cm and 1 x 92cm, all exhibit a slight tendency to do that, I use Fan Mates on them all.
     
  7. dekoded

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    I have used 'PAPST' fans in my computers and they are VERY quiet,(12dba) but they can be a bit tricky to get hold of.
    RS sell them, and I did get some from kustom pc but I think they have changed to silenx now, you could try here:
    http://www.pcsilent.de/en_manufacturer_Papst.asp

    As KraGorn said, a fan mate will also help, or you could just mess with your psu connectors to obtain either 7 volts or 5 volts to supply your fans :smashin:

    (careful, some fans need to have a minimum voltage to start them spinning!)
     
  8. Werner

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    you can go about this a number of ways. For "wind" noise, the problem is the shape of the vent holes. Slots/grills will whistle, round holes will tend to make a sucking sound, while the best holes are hexagonal. They provide minimum noise whilst having the largest FAR (free air ratio...the difference between metal used and the size of the holes) If you can find a case with hexagonal holes, you have stage 1 completed.

    Secondly, if the fan is really close to the holes, it will create turbulence and you will hear this when the fan is on. Fans move air, mMoving air is known as wind, and when wind hits something it create a soundwave. Perhaps a 1cm spacer (homemade?) can be used to move the fan slightly away from the grill.

    Thirdly, you can use a fan mate/7v mod/resistor trick to lower the voltage, which will change the speed of the fan and would take off the whining noise. This is a "set it and forget it" solution. If your pc is hot the fans will still spin slowly. Not good....

    Fourth, you can try out a program called speedfan (freely available, google it) which will allow you to dynamically control the speeds of the fans via the motherboard headers based on criterai you specify, typically the cpu temperature...cpu gets hot...fan will spin faster...cpu cools down, fans spin slower. This is quite an elegant solution. Most htpc's are overpowered for playng music/dvd's, so in general use the fans will spin slowly and you wont hear a thing.

    Last solution, crank up the volume :thumbsup:
     
  9. mephistopheles

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    Can also recommend Papst fans. You can get them at Farnell InOne here:-

    http://uk.farnell.com/jsp/home/homepage.jsp;jsessionid=QBEYSJOEXFL4LQFIAEWSFE4AVAAS0IV3

    Papst also does a range of Variofans, which include an NTC (you solder it into the negative side of the fan circuit) to automatically control the fan speed between 30 - 50C. Other NTCs with varying ranges will also work.

    Panaflo also very quiet are available from Dorothy Bradbury here:-

    http://www.dorothybradbury.co.uk

    Resonance can be a problem, too. QuietPC (or maybe it was Overclock - nor OverclockersUK!!!) does a range of silicone gaskets, which I've found helpful.
     
  10. Pbryanw

    Pbryanw
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    First of all thanks for all the advice. This is my first thread so I'm delighted with all the help I've received. It's been really useful to me. I think what I'm going to do is remove the case grills for my fans and hopefully get rid of the sound the air makes flowing through them. I'll try the SilenX fan out and see whether it's quieter then the Acoustifan. If not I might consider purchasing a Papst fan and then I'll probably have to write a case fan group test review or something won't I? :)

    I'll report back once I've got everything installed and cut out.

    Oh, and what a useful program Speedfan is - thanks for that suggestion :thumbsup:
     
  11. jameson_uk

    jameson_uk
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    Just something to think about first. A lot of people dismiss the SilenX published figures and I have several in a few cases and I tend to agree. When compared to the Acoustifans I reckon they push more air but are noisier. Also it appears that the SilenX fans are actually standard fans with an inline resistor but cost a packet :eek: (you are probably better off just getting a decent fan and an inline resistor as it is about £10 cheaper)

    Having spent days trying different fans in the pursuit of quietness I no longer believe it is worthwhile spending loads of money on so called quiet fans. These tend to push little air and are really expensive. Instead, you can easily mod your existing fans to run off 7V or 5V which drops the speed and hence the noise. Also the difference between 80mm and 120mm fans is quite noticeable as you can run a 120mm a lot slower (and hence quieter) but still push the same amount of air as a fast running 80mm. (If you really want case fans, you could consider making the hole big enough for a 120mm fan)

    I also came to the conclusion that case fans are not really needed. I have cut them down from 4 to 2 with no difference in temps. If you are not actually having problems with your system overheating then you probably do not need any extra cooling and if it is only the CPU temp you are worried about, you would probably be better off just replacing the heatsink / fan on the CPU.

    So all in all, here are a few things to check out
    Quiet PC (particularly the Zalman multi connector as this is the easiest way to see the difference of your fans running @ 5V)
    Kustom PCs (they will do any mods for you and cut out the grill and make up to 120mm)
    Fan Controllers (check these out as they allow you to adjust fans as you like and some of the automatic ones are fantasticly quiet but also very safe)
     
  12. groovyclam

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    After trying many fans ( including SilenX ) I am in agreement with jameson_uk
     
  13. Pbryanw

    Pbryanw
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    I think I'll give the resistors a shot if my fans are still too noisy once I've modded the case. Anyone know whether it's worth buying one of those Cobalt3 Pyramid V fan controllers? They're quite expensive but I suppose might be worth buying if they work properly. One more thing - would buying Anti-vibration Fan Gaskets from Quietpc make any difference to the noise?
     
  14. jameson_uk

    jameson_uk
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    Worth a go. These just reduce the voltage to the fan and hence reduce the speed. I think they might drop it to 7V. It is easy enough to use a standard power connector to run fans at 5V, if you don't mind swapping the wires round which does the same thing.
    No direct experience but I hear they do a job. As to what extent I do not know and I would have thought that it is unlikely they would be that much better than just the resistors. The mCubed stuff however look far more interesting (and a bit more expensive). But this has the ability to actually reduce the fan speed to nothing. I have seen reviews which say that this is very good.

    It depends. If you are actually noise because either the fan is vibrating against the case or it is sending vibrations through it then yes (this is quite common on older steel cases). If not then no. I would imagine that if you put your hand on the case next to the fan to prevent any vibration you should be able to feel if any is getting through and if this has any effect on the noise level.
     
  15. Yandros

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    I can also recommend Papst 80mm fans.

    http://www.chillblast.com/customer/home.php?cat=70

    I've used both the normal and temperature controlled versions, and both are outstanding. In an office environment we can't actually here the PC at all (2 intake 1 exhaust), unless you're about 1ft from the vent.

    I can also recommend fan controllers. I tend to use Zalman CPU coolers, which come with the speed dial, They're great for getting the best noise/performance compromise. They also allow you to avoid hitting any nasty resonant frequencies. A few other noise busting tips....

    Use acoustic lining (Acousticpak is good) particularly if it's aluminium.
    Use dampers on your fan mounts and HDDs.
    Tighten/loosen mounting or case screws. I tracked a nasty drone down to a HDD with over-tightened screws, which was passing the vibrations on to the side panels.
     
  16. Pbryanw

    Pbryanw
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    Got my SilenX fans today and what a difference. Noticeably less airflow (supposedly higher cfm than Acoustifans though???) but a lot, lot quieter then the Acoustifans. Tried CS: Source, which used to lock up my system as my graphics fan overheated, it now runs fine. Plus they were a doddle to install with the silicon fan mounts (compared to screwing them in). They still produce noise, I guess that's expected, it's just that I can live with the amount of noise they produce. Still may saw off my fan grills, but this purchase has meant that's now an option not a necessity.

    Anyone in the market for some brand new, hardly used Acoustifans? :D
     
  17. Da_Rude_Baboon

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    You can make your own from old mouse matts. The best ones to use have a neoprene backing with a plastic face. You can ussually peel the backing away from the plastic (the cheaper the mouse matt the easier it is) which leaves with a thin sheet of spongy neoprene perfect for making gaskets.

    As for fans your best to go for Papst, Panaflow or noiseblockers. Silenx fans are very expensive for what they are and as already mentioned, their performance figures a very contentious.
     
  18. Pbryanw

    Pbryanw
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    Just as a final note, I filed out my fan grills using my new Maplin needlefile kit and the noise produced by the fans reduced greatly. So much that I can hardly tell my fans are there - noise is almost back to pre-case fan installation levels. So I can go back to enjoying an almost silent pc :) If in doubt, file it out :thumbsup:
     

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