Mac Pro - Solving the resonance problem with hard disks

Discussion in 'Mac Pro' started by ashkanfardost, Jan 12, 2008.

  1. ashkanfardost macrumors newbie

    Jan 12, 2008
    Hi all,

    I've been browsing through the internet regarding the problem with resonance on the new Mac Pros (maybe on the Power Macs as well), where the hard disks vibrate/resonate and thus making the entire Mac Pro case producing a very annoying sine wave resonance sound. I've found a couple of forum threads with suggestions on how to reduce/eliminate this sound, but none of the methods did work for me. Some methods required material that many people don't have at home, and neither did I, so I can not tell you if those methods were any good.

    Anyway, since many people (especially owners of Samsung hard disks) are experiencing this problem, I thought I'll share my solution as well since it only requires material most of us already have at home.

    Source Of The Problem

    If you remove a HD from one of the bays and hold it on each of the long sides with your thumb and middle finger respectively, you will hear a short vibrating sound when you quickly tap the rectangular metal plate of the metal drive carrier (the metal plate covering the back of your hard disk, in other words the metal plate that is visible when you open up the hatch of your Mac Pro). This vibrating movement will be constant when the hard disks are spinning, which produces an almost constant vibrating sine wave sound.

    Solving The Problem

    Materials needed: towel + scissors

    Cut out a piece of towel with the same width as the rectangular plate on the metal drive carrier. The length should be approximately 15 cm (6"). Now fold this towel piece in order to create a "towel block" which will fit in the space between the metal plate and the back of the hard disk. It shouldn't be possible to insert the "towel block" inside that space without a little force. If it isn't thick enough, it won't dampen the vibration. I had to force it in with the help of a pen, however not too forcefully as I didn't want to damage the hard disk. If you feel you might damage your hard disk, reduce the thickness of the towel block a little bit and try to insert it again. If it's thick enough, you won't hear that short vibrating sound when you tap the metal plate anymore.

    Now simply insert the drive carrier back into the bay and enjoy a silent Mac Pro experience :)

    I use all the four drive bays, with four 300 GB hard disks, and the vibration sound is completely gone. I hope this works for you too!

    Attached Files:

  2. Bass108 macrumors member

    Oct 20, 2007
    aww man samsung huh? and i was going to with all 3 samsung drives to cut down on noise...

    maybe hitachi is the way to go?
    i want 1TB drives and WD doesn't really have TB drives for RAID

    can paper towels be safe next to your hot drive?
  3. THX1139 macrumors 68000


    Mar 4, 2006
    First off, the harmonic resonance problem can occur with any drive. Mine did it with WD and Seagates. It's an Apple engineering problem, not necessarily a drive problem other than some drives do vibrate more than others.

    I solved the problem in a similar manner, except I used high density foam rubber instead. Something about stuffing towels inside a MacPro seems kind of ghetto. Anyway, I went to a local hardware store and in the power tool section they had pads of black high density foam rubber of various thickness. I bought a square foot of quarter inch for a buck or two. I took it home and cut it into strips just wider than the openings around the drive. I carefully stuffed pieces in so as to not bend the sled or damage the drive. I put the drives back in and the problem went away.

    Another thing I've noticed. The drives have a tendency to settle down after you have them running for a few months.

    Towels will probably work too, except they might lose compression over a long period. I also don't like the idea of having fabric inside of a computer that can get very hot. High density foam rubber should last longer and not catch fire if there was a short.
  4. Wild-Bill macrumors 68030


    Jan 10, 2007
    Wow.... Apple engineering is just Aces & Eights these days, huh? :rolleyes:

    Thanks for the info. I've got 3-5 week to find the foam, buy the foam, and cut the foam.
  5. ashkanfardost thread starter macrumors newbie

    Jan 12, 2008
    Should've mentioned this in the original post, my bad: I've tried foam rubber already. Contrary to what one would think, the foam rubber I used lost compression after a couple of days, while the fabric towels/cloth pieces have kept the machine quite for 3 weeks now. That's why I was so happy with this solution, I guess I'm a bit lost in the moment of revelation heh.

    Let me know what kind of foam rubber you are using, if you've been able to keep the machine quiet for a longer period. I wouldn't worry about the fact that it's fabric inside the computer though, I doubt it would catch fire from a short circuit. But it's f***ing ghetto I give you that :)
  6. waremaster macrumors 6502

    Aug 27, 2006
    To solve this problem you do not need any foreign objects in the machine such as foam or rubber matting simply put a slight bend where the arrow is. What is happening is the end of the caddy is resonating on the bar that spans from front to back of the case as well as the locking mechanism. By putting this slight bend in the caddy you are providing enough clearance and enough pressure on the locking mechanism to stop the noise. This bend is so slight you can’t even tell it’s there when looking at the drives installed in the machine but it does stop it believe me.

  7. THX1139 macrumors 68000


    Mar 4, 2006
    It was the industrial black foam rubber that is used to set large powertools on to keep them from vibrating. I found mine at ACE, but I suppose any hardware store would have it. I put it in last year and my vibrations are still gone.
  8. THX1139 macrumors 68000


    Mar 4, 2006
    I bet you discovered bending when the drives were causing you a lot of frustration. :D When mine were vibrating, I'd get so annoyed that I wanted to beat the crap out of my computer. ;)
  9. waremaster macrumors 6502

    Aug 27, 2006
    Nope simply remove the cover and touch the caddy. You can feel the vibration and it stands to reason that since the lock at the back of the case has to touch the caddy in order to lock it in place that if there is any play it can make noise. By putting a slight bend it puts pressure on the mechanism and moves the edge of the caddy away from the rail that spans front to back so no more noise.
  10. newtech macrumors 6502

    Jun 2, 2007
    The way people complain about noises in Mac's I wonder how any of them could have stood the noise of an IBM PC/XT.
  11. macro macrumors member

    Dec 15, 2007
    I think you all have discovered the mind set for the pyramids at Gaza. Good info though. I have to talk to Rah to see if he/she/it ever used foam or towels?
    OK, I'm just joking as I haven't done any HDD upgrades as yet. I love the simple, yet, effective mental resources that you provide for this problem. Nothing but respect as to the "muffler loose on the truck" remedys. Whoda thunk?
  12. kirkbross macrumors 6502a


    Mar 6, 2007
    Los Angeles
    Puh leeze... anyone ever own a dual 867 MDD G4?

    Loudest Computer Ever. Thank you.
  13. ashkanfardost thread starter macrumors newbie

    Jan 12, 2008
    Yeah, PC's and such machines are much noisier unless you spend some extra bucks on silent cooling. The problem with the Mac Pro resonance though is that the sound has a very low frequency, and it's not constant. It's like having a half-dead creature in your room grunting on and off every third second, kinda pisses you off after a while :eek:
  14. ReanimationLP macrumors 68030


    Jan 8, 2005
    On the moon.
    I'm pretty certain that the PC XT only had a fan in the power supply.

    Unless it was insanely loud, I doubt they could be bad as some computers I've seen.

    My PC makes a humming noise when your close to it, having to do with 5 120MM fans, a 200MM fan, a 75MM, an 80MM, 40MM, and a 92MM. :D

    Doesnt bother me in the least.
  15. lloyd709 macrumors 6502

    Jan 10, 2008
    This vibrating noise was driving me nuts but thanks to the advice on this thread - in particular the bending advice - I now love my mac again!

    Thanks guys
  16. orpheus1120 macrumors 65816


    Jan 23, 2008
    Does the resonance happens for upgraded HDs that we buy ourselves?

    How would one put a bend onto the rectangular piece of metal? Hammer... or.. lol.. Seriously, how would one go about doing it harmlessly?
  17. feedmeastraycat macrumors newbie

    Apr 13, 2008
    Extra Slim Filter Tips

    Wedge a couple of these between the aforementioned bar running the length of the chassis and top of the Hard Drive Brackets as well is a fairly neat solution.:confused:
  18. lloyd709 macrumors 6502

    Jan 10, 2008
    You can bend the metal easily by hand by unscrewing the casing from the drive, placing it on a table (with half of it on the table and the other half off) and applying very gentle pressure to the half off the table. You need to bend it about a millimeter - just enough to stop it vibrating against the metal plate above. It's a very easy and neat solution - it saved my sanity - so thanks again to whoever was the first to brave it!!
  19. Scoox macrumors newbie

    Jun 8, 2008
    Very well put lol

    I have a 320GB and a 500GB drive in my MacPro. The 500GB drive is the one that came with the machine, and the other one I purchased afterwards. Both are the same model, just different size.

    The 320GB drive does not make any noise and when I put my hand to it I cannot feel any vibration. The 500GB drive, by contrast, vibrates which results in an intermittent resonating hum.

    Both drives spin at 7,200 rpm but the larger drive has more platters and therefore any vibration issues will be amplified. Vibration in hard drives is not uncommon and the ones that vibrate more are still within tolerance levels. Of course nobody wants to buy a product that's too close to the tolerance limit, but you don't find out till you buy it!

    The point is: nothing is perfect, so rather than trying make perfectly silent hard drives, manufacturers increase tolerances (which brings down cost) and recommend damping using rubber grommets or what have you.

    Unfortunately hard drives in the MacPro are attached to the case too rigidly: they plug directly into the motherboard via a rigid plastic connector, and the metal sleds have very small rubber grommets which only provide a microscopic amount of damping; predictably, most of the vibrations from the hard drives are transferred intact to the motherboard and the chassis, which happen to resonate.

    By contrast, my one-year old PC has a pair of 500GB Seagate drives which vibrate just as much (or even more than) the ones that came with my MacPro. The drives are mounted on much larger rubber grommets and as a result they are actually quieter.

    In conclusion, you may be lucky and get a quiet hard drive, or you may want to get a smaller drive which in general will be less prone to vibration, but remember that the MacPro drive-mounting scheme is the main cause of this problem.
  20. hms84 macrumors regular

    Jul 28, 2007
    I doubt the size matters...
    I just bought 1TB WD HD, It works fine without any noise
    I have 250 GB from Apple, SO ANNOYING
    and 80 GB WD for windows ...... no sound
    and 1 TB WD for media .... no sound either

    I think the drive bay have some problems, I'll try switching between them and see.

    The common thing in the problem is the BAY (NOT THE HD) since we all have different ones, and the place too!

    and if we go deeper in the peoblem we can see another common thing that ALL THE HD HAS BEEN ATTACHED TO THE BAY BY APPLE, so may be the problem is there (the manufacturing). I'll look on it when I go home. (^_^)
  21. FireSlash macrumors member

    Nov 11, 2007
    1) Floppy drive access noise
    2) Bearing noise from old hard drives (Seriously. Not quite as loud as a huge fan array, but much more annoying, since it had an odd dissonance to it, and was easily five times as piercing.
    3) The fan was pretty damn loud compared to modern fans.
  22. BarneysPosse macrumors newbie

    Jan 15, 2008
    I never have any noise troubles with my MP.
    The solution?
    Keep the metal music up real loud :D
  23. lyndon macrumors newbie

    Jun 28, 2008

    Yeah, thanks that was extremely funny. Keep it coming. :eek:

    What eventually worked out for me was simply to take out my Raptor drive, inserting it again and voilà: the resonance from hell was gone. I tried lots of other things first but this seems to be the best thing to do. Yank it out and shove it back in.
  24. Scoox macrumors newbie

    Jun 8, 2008
    Well that didn't work for me. I had my hdd replaced by Apple and the new one does not vibrate at all which is great. However the new one is a Seagate drive which makes horrible noises when seeking (rrrtteeek, tack, rtteeek, rtteet...). So back to Apple Care...
  25. hugodrax macrumors 6502a

    Jul 15, 2007
    You should have heard the noise my home build PC towers on those big ANTEC cases with multiple fans sounded like. These Mac Pros are amazing in terms of how quiet they are compared to my leaf blowers.

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