SPCR

I have a CoolerMaster ATC aluminum case (I believe the exact model number is ATC-201 or similar to that). There is a "buzz" sound eminating from it, and unless the TV or music is on, it dominates all other background noise.

If you are familar with this case, it comes many fans, but I have turned most of them off. I have a CoolerMaster PS with a single 120mm fan always on low. I bought a Zalman heatsink fan combo (CU700) which runs on low to replace the Intel retail P4 unit. There is also an 80mm fan blowing out the back right below the PS (the only case fan I didn't disable).

I have two hard drives, both mounted in the front. One I left as is; the other I decided to try out the Zalman heat pipe cooler on. It has the rubber mounts to help dampen out the sound. I would estimate the hard drives to be in the 45-55db range.

After all of this, that annoying buzz is still there. At work we have some 1.5" think eggshell foam for sound proofing rooms. The cost of foam made and cut for computer cases is surprisingly high, so I took home a small sample and cut it up and placed it around the case to see if would make any difference before spending any more money..... but nope

I think the main problem is the aluminum case; the sound is reflecting and bouncing all over the place. For example, the new heat sink fan I installed is nearly silent when the case is open and I place my ear directly over it. However, as soon as I unplug all other devices, and close up the case, the fan becomes "louder". Is it a lost cause to try and quiet this system? My last resort would be buying a new case such as the Sonata. I haven't gotten a chance to research the case, but I know it is advertised as a "silent" case.

Thanks for any tips.

Have you tried to put you hand on the sides of the case and verify if the buzzing goes away or is attenuated?

If so, you probably need heavier dampening material than just the eggshell foam to cut out the buzzing, or if this foam is heavy enough already, you probably need to actually stick it to the case, rather than just surrounding it.

I know my el-cheapo superflow aluminium case does buzz and when I hold it with both hands the buzzing does "disappear"...!

Holding the sides of the case does not make any difference. I think the buzz is coming from the internal noises being echoed within the case. Vibrations give more of a rattling type sound.

The hard drives sound the loudest. But if I unplug both hdds, and leave just the fans running, then noise generated by the fans becomes very audible.

It seems as though I would need to line the whole case with foam. I wouldn't mind spending the money on acoustipaks, but only if it actually makes a difference.

Wallst32 : Welcome to SPCR

Have a look at the reccomended fan section or the fans forum on this web site. Also use the search feature to search for "EAR fan mount" which will return results like this http://forums.silentpcreview.com/viewtopic.php?t=8274

Next search for "hard drive suspension". There are many suspension methods available including the article by Aphonos in the articles on the site. Here is something you can buy from compussr as an alternative
http://forums.silentpcreview.com/viewtopic.php?t=20776

A hint when using the search, dont use the "" and search for all the terms. Come back with more specific questions and people will help you on your way.

Good luck!

Acoustipack helps by soaking up vibration and high frequency sounds. Something to consider for aluminum cases.

But I don't think that's necessarily the solution you need.

Try this: disconnect the power cables to your hard drives and then your fans. Put the side back on and see if you still have the buzzing noise. Then try it with the fans plugged in (well, the only ones you plan on using). Then try it with the hard drives plugged in, but not the fans.

If it's the fans, try using rubber sticls or earplugs to decouple them from the case (undervolted as well, if they're not already). If it's the hard drives, suspend both using rubber or else lay them on foam (or one one way, and the other another). I have a steel case,and I still had a good amount of resonance from the hard drive. It was on foam in a Smart Drive, but the drive was unintentionally touching the side panel, and the resonance traveled to the top of the case!

It's possible that BOTH are responsible for the noise, or even NEITHER. The noise could also come from the CPU or PSU fan, or coil whine from the MB or PSU.

*EDIT* I had somehow missed the bit where you said you had all other devices disconnected. Still, it COULD possibly be from the PSU, I didn't see a coolermaster PSU on the recommended list. Try disconnecting the Zalman fan power for a second and close the case. See if it still makes the noise then. Still, even if the PSU is the problem and you replace it, you might want to consider the advice abovel; aluminum cases are louder due to vibrations from HDs and fans. Don't know about an echoing effect, sorry.

It sounds like an unfortunate combination of high vibration drives and a flimsy case. What HDDs are they?

7200rpm drives have their primary spin freq noise at 120Hz. If it is a 10K drive, it is at 167Hz. A 5400 will be at 90Hz. (Hz = cycles/sec; rpm=cycles/min, so divide rpm by 60 to get Hz). Any HDD will have at least some degree of higher harmonics at multiples of the primary harmonic (for a 7.2k drive, it'd be at 240, 360, 480, etc Hz), and the case will exaggerate all of these. The character of the buzzing is determined by the relative levels of all of these different sounds.

A soft suspension is the only way you'll eliminate this noise. But if the vibration is high enough, it could even be transmitted through the air, so some damping material on the nearest case panels may be necessary. Don't go for soft foamy stuff; you need the heavy rubbery stuff (mass damping) to stop the panels from vibrating.

Finally, you might consider both suspension AND a change of HDDs... AND a change of case. Just depends how much time & effort you want to put in vs. how much $ you want to spend vs. how quiet you want.

A generous helping of acoustipack will definately help. You really should narrow down exactly what the buzzing is first though. I would simply remove the side panels and listen to what's making the most noise though and tackle those parts first.

Acoustipack is great and will make a decent aluminum case quiet, but it won't solve the problem of having loud components to begin with.

wallst32 wrote:I have a CoolerMaster ATC aluminum case (I believe the exact model number is ATC-201 or similar to that). There is a "buzz" sound eminating from it...
After all of this, that annoying buzz is still there...
I think the main problem is the aluminum case;... My last resort would be buying a new case such as the Sonata.

Do what I did with my CRAPPY Coolermaster(junk)... Replace it with a good case.
http://forums.silentpcreview.com/viewto ... highlight=
Stay away from that Brand altogether and don't waste your money trying to silence it by buying costly Foam material...
In my case I replaced it with an Antec 3700BQE (which is the original of the Sonata... without the holes on the side)... I am very happy with it... it costs less and, I think, is also quieter than the Sonata (side holes) :
Newegg: $80.49+15.99 shipping= $96.48
BB= $99.99 +Tx

N.B. Most of the product reviews you see are usually rewarded in one way or another i.e: Newegg gives a Cap or a Tshirt... other places some discount and many of the Website "Reviewers" get cold cash for Positive reviews...
I submitted a review to Newegg after I bought mine... but it was never published!

Most likely you will need to suspend hdd. To be honest I love ATC-201 case. Once you swap out fans and lowers voltage, it's sturdier construction over lian-li case makes it much quieter than just about all lian-li case for similar airflow level. Acoustimats do help on this case.

Put One gallon of bottled spring water on your case. I'm quite seriouse.