Noise reduction

[zsa]

I've got a number of machines that my wife is threatening to ban from the house unless I can find a way to quit them down. Since I don't want to live outside, I've replaced two case fans and the cpu fan on one system with fans that are rated anywhere from 10-15 dBA less than the originals. I thought this would have cut the noise level about in half, but instead they actually seem louder.

I'm thinking that maybe it's vibration travelling through the case. Antec has some "Noise Killer" gaskets that might work. Alternatively, I've seen some litttle plastic stand-offs that apparently keep the fan body away from the case.

Does anyone know if this will make a significant difference? Or are the dB ratings just complete nonsense?

The new fans are Kingwin F-10B's, 25 dBA/32 CFM. The other thing I can try would be to go down to an Enermax variable speed fan that ranges from 18-29dBA.

Anyone have any recommendations?

 

[Cerb]

I don't know about the Antec things, but will try them next time I need anything.
The blue plastic isolators, like these, work very well.

The Enermax fans are fine, but do have some motor whine. best to go with Panaflo or Aerocool fans to cut down on that while not losing much CFM. Also, a fan bay controller wouldn't hurt a bit.

Also, depending on the case, you can get tons and tons of noise from near the exhaust, if the CPU fan, exhaust fan and PSU fan are all close to one another. I haven't found a good way around that problem as of yet , and that's currently 100% of the annoying noise coming from my system.

 

[mdcrab]

Tonight I bought a roll of AP/Armaflex foam insulation tape at Home Depot for approx $9. It is 1/8 thick by 2" wide by 30 ft long. Plan to use it between PS and case mounting areas, around case fan interfaces with case and possibly on side panels. It is made for thermal insulation by spirally winding around pipes and fittings, but figured I would try it for acoustic signature reduction on my PC.

It appears to be neoprene and has a nice smooth black surfaces w/ removable paper on self adhesive side.

mdcrab

 

[Ken90630]

Hi, Zsa,

Welcome to Anandtech.com.

For starters, you can get some fans that are considerably quieter than those Kingwins. SilenX, PC Power & Cooling ("Silencer" fan), Vantec ("Stealth" fan) and Papst, among others, all make fans rated at 20dBA or quieter (I think the SilenX's even go down to 15 or 13 dBA or something, if memory serves). Anyway, I'd start there. Twenty-five decibels is still kinda audible, while 20 and below is ostensibly inaudible.

Having said this, the decibel ratings for fans are a continuing cause for debate. The prob is basically that most fan makers don't publish their testing protocol with their specs, so you don't know how far away the microphone was when they measured the noise output. Was the mic right next to the fan? Or a foot away? Or ten feet away? Reputable testers usually test at 1 foot (or meter), then report the dB reading, but there's no 'law' requiring anyone to do so. Comments from users of the aformentioned fans seem to indicate they are, for all intents and purposes, silent.

Panaflo industrial fans are also very quiet and have a great reputation around here for quietness, longevity and air output. I'm planning on replacing my stock CPU fan with one as soon as I put my new system together shortly.

I've only worked with a handful or two of computers over the last 10 years or so, but I can't say I've ever run across one with a 'vibration' problem transferring noise thru the case. But, that doesn't mean it can't happen. My personal recommendation is to start with any of the aforementioned quieter fans, then if things still aren't quiet enough to keep your wife from banishing you to the front yard and a cot :Q , try a fan speed controller or some vibration-dampening measures. Incidentally, the SilenX fans have temp sensors that slow down and speed up the fan according to internal case temp. Some of the others probably do as well, and I know Enermax makes a multi-fan controller that also has temperature probes.

As you probably know, the biggest culprits when it comes to PC noise are almost always the power supply and the video card fans, so I'd look there first. PC Power and Cooling makes a nearly silent PSU, as do Zalman and a couple other manufacturers. Some of the guys here at Anandtech replace their PSU fans with Panaflo L1As, but I haven't tried that myself.

As you may already know, there are also a number of Web sites dedicated to quieting PCs, like QuietPCusa.com, Silentpcreview.com and others.

Hope this helps. Good luck.

 

[zsa]

Thanks for all the help.

I'm going to run down to Home Depot and see what sort of stuff they have that'll reduce vibrations.

The Kingwin fan dB ratings are definitely baloney. Little quieter than a 727 at takeoff, but not by much. Live and learn

I'm looking at buying a bunch of Zalman ZM-F1 fans. They are sold by a lot of the "quiet PC" specialty sites. They have RPM sensing, which apparently the Panaflo's don't, and they're pretty cheap (about $5 apiece). The Aerocools look good, but every model they have seems to have LEDs, which are pretty and all but not quite the thing for the guest bedroom.

Not sure if the Zalman variable speed feature is going to be a problem or not. Hopefully the enclosure is cool enough to have the fans running at low speed most of the time.

I'm thinking I'll also wind up doing something about the power supply fan, either yank it out and replace it or maybe remount the supply with some sort of damping material.