Fan mufflers?

MrMajestic · Post by **MrMajestic** » Mon May 12, 2003 1:46 pm

Had anyone tried a ready-made fan muffler or perhaps built one themselves? If you've tried, whats the verdict? Im thinking of building a custom case with a bunch of 120mm fans, and Im wondering if I should put mufflers on them or just a duct with some kind of absorber inside.

Td_nw · Post by **Td_nw** » Mon May 12, 2003 4:48 pm

No personal experience, but...

Everything I have read or heard is that they kind of defeat themselves by blocking the air being exhausted by the system, impeding the airflow of the case, causing your fans to have to work harder.

More RPM on fans = more noise.

Better off just optimizing your airflow and keeping yours fans at low speed.

Yomat · Post by **Yomat** » Mon May 12, 2003 6:12 pm

Have to concur.

Mufflers only remedies crappy fans. Airflow is still airflow and it makes sound. Better to get a fan that produces less noise with the same airflow. Preferably one that you can control the speed on.. so that you can adjust your heat/noise ratio to a comfortable level.

To make a good muffler you would need to muffle the whole computer, use long pathed noise dampened air ducts and use big high cfm fan to build pressure enough to transport the air.
Like this (In german but the pics will show you the idea): http://www.carsten-buschmann.de/schalls ... chnitt.htm

Although that design would probably do much better by using an intake fan too. Normal pressure is always the best. With under- or overpressure you will get less predictable ventilation behaviour.

MrMajestic · Post by **MrMajestic** » Mon May 12, 2003 11:48 pm

Hmm, I might reconsider the muffler idea then. Im not so worried about the fan noise as much as the noise from the rest of the computer slipping out of the fan holes. How about a duct lined with soundabsorber?

AndrewC · Post by **AndrewC** » Tue May 13, 2003 5:30 am

That still gives sound a straight way out of the case. The point of the muffler is to offcenter the fan hole and the final hole to prevent sound from escaping. The duct would work if it was something like dryer hose and was bent as not to provide a direct exit for sound.

Hope that helps.

Td_nw · Post by **Td_nw** » Wed May 14, 2003 3:40 pm

Wow Duct Deja-vu.

Deja-vu

Raygun · Post by **Raygun** » Mon May 19, 2003 9:15 am

Now from theory to practice.

I bought a PSU muffler to test it and to try avoid breaking the PSU open to replace the fans and thus the warranty.

All of the above posts may still be true, if you have an already quiet PSU. The one I have been testing it on is an Antec TruePower. The sound difference is significant. The PSU exhaust was clearly the loudest in my system before. Now I can hardly hear it any longer.

What about the temperatures? No difference. If any; 0.5 - 1 degrees Celsius. On both CPU and PSU. MB no change.

I do suspect some of the PSU noise from the 92mm "belly" fan may slip past the under volted 120mm Papst out the back.

Tested on a AMD Thunderbird 1.33 in an Antec SLK3700 case with 20 minutes of Folding@Home with and without muffler.

jamoore9 · Post by **jamoore9** » Tue May 20, 2003 9:29 am

Where'd you get the PSU muffler?

Raygun · Post by **Raygun** » Thu May 22, 2003 8:06 am

jamoore9 wrote:Where'd you get the PSU muffler?

http://www.gtek.se

golemB · Post by **golemB** » Thu Jun 12, 2003 10:54 pm

I bought a PSU muffler from http://www.muffledcomputing.com for about 30 bucks, and it works reasonably well. (Contrary to their recommendation, I decided to apply the adhesive so that it covers not only the PSU fan but also the 80mm case fan right below it, which works alright on my case.) However, the air coming out definitely feels a bit warmer than before, especially when the CPU is at high load.

Now having said that, I'm still unhappy with the quality and amount of noise - apparently it's mostly from my PCP&C Turbo-Cool 425's noisy fan. I'm torn between trying to sell the thing on eBay (it was over $100, and purchsed when I thought that bad power was the source of system instability, doh) versus replacing its fan.

I'd say the manufacturer's claim of about 10 dbA reduction is probably accurate, and it does help during daytime when traffic noise masks the PC, but at night there is a whine or other high pitched noise that grates slowly at my nerves. (Probably explains why I am now insane enough to waste hours surfing this site and contemplating all manner of expensive and time-consuming solutions.) It's sad, but yes, the human auditory system gets more sensitive the quieter it is. So the muffler reduces quantity of noise, but the quality is my currrent problem...

(Note: I do not yet have any type of speed or voltage adjustment to any fans, and it's quite possible that my hard drives are contributing to noise, but I can't tell b/c of the @#$! power supply.)

blahblahbloo · Post by **blahblahbloo** » Tue Jul 29, 2003 5:49 pm

golemB wrote:I bought a PSU muffler from http://www.muffledcomputing.com for about 30 bucks, and it works reasonably well. (Contrary to their recommendation, I decided to apply the adhesive so that it covers not only the PSU fan but also the 80mm case fan right below it, which works alright on my case.) However, the air coming out definitely feels a bit warmer than before, especially when the CPU is at high load.

How much warmer? And is this also the case if the muffler only covers the PSU fan?

golemB · Post by **golemB** » Tue Jul 29, 2003 6:29 pm

blahblahbloo wrote: How much warmer? And is this also the case if the muffler only covers the PSU fan?

Warm, but not hot - like a warm exhalation from a person's mouth. Sort of like the difference between a hair dryer on "warm" rather than "hot".

I currently can't really put the muffler over just the PSU fan, b/c the top case fan needs to be covered as well. The reason for this is that I added a second rear case fan to blow air into a homemade duct and onto my CPU fan, so now the muffler serves to reduce cycling of warm air between the intake duct and the output case fan just above it. This has led to a definite decrease in my CPU temp, which in turn led to a decrease in crashes while playing a 3D game in Windows 98. (Linux never had a problem with heat, though, so possibly the 3D card is contributing interior heat.) Another plus is that I now have positive case pressure (three intake fans to two outputs) which reduces dust.

The bad news is, my desktop is now so loud that I wind up turning it off at night, which is probably just as well for the environment... It's okay during the day but grating on the nerves when trying to sleep. Maybe I should add a homemade muffler to the rear intake fan...

All this goes to show that my efforts (involving sweaty hours with a metal cutter and a bastard file) to increase airflow and quietness at the same time were a bit counterproductive. After I bought four Vantec Stealth 80mm fans, though, I felt it was better to try to use them than to invest more money in Panaflos and an expensive CPU HS/F. Now I realize I should hve paid more attention to the wisdom here.

golemB · Post by **golemB** » Tue Jul 29, 2003 6:42 pm

Oh, and thanks for the deja vu ducting post above - I used the decouple-mounting for the rear case fans, and that seemed to cut down on vibration.

I made my duct out of cardboard, and it doesn't output exactly on top of the CPU fan, so that's why I added a fan to give it some juice. I also experimented with reversing my CPU fan to draw air up through the HS and up to the duct (with the case fan set to blow out as well) but that made a weird grinding noise and resulted in less thermal performance.

If you can make a bent duct using soft foam and/or flexible tubing, it should be easier to do without another case fan, and possibly allowing external air to cool the CPU will help overall.

In any case (pun intended!), I think a muffler, like any other mod, must be considered as a part of a whole effort to achieve a goal. If, like me, you can't quite afford to get a very-quiet PSU and a quiet, high-performance heatsink for your CPU to satisfy both thermal and noise requirements, then you may have to do some tinkering. Or, like me, maybe you find the process more entertaining than just buying a series of expensive parts.

Of course, that part might fall through if you wind up tossing out your experiments and settling for expensive parts. Mike C can attest to the never-ending cycle here...

Dr. Jim Pomatter · Post by **Dr. Jim Pomatter** » Fri Sep 17, 2010 11:39 am

I hate to bring a post back from the dead, but this thread comes up at the top when trying to find info about fan mufflers.

I don't like to "mod" my parts, due to the PITA of getting a good clean look. I have a couple of good power supplies, one that I want to quiet is the OCZ gameXstream 700.

I can't find any ready-made mufflers any more. There were a few compaies making them in the 2003-2005 time frame. The Silverstone PSU Muffler from 2005 is not for sale anywhere and the only one I have been able to find is the new Lian Li one.

Head over to the post and poll in the power supply area, and tell me what you think.

SST Guy · Post by **SST Guy** » Sun Sep 19, 2010 6:52 pm

Dr. Jim Pomatter wrote:I can't find any ready-made mufflers any more. There were a few compaies making them in the 2003-2005 time frame. The Silverstone PSU Muffler from 2005 is not for sale anywhere and the only one I have been able to find is the new Lian Li one.

SilverStone's PSU muffler, the PP02, is still available for sale. Places like Amazon still has them in stock.

golemB · Post by **golemB** » Mon Sep 20, 2010 5:28 am

Dr. Jim Pomatter wrote:I hate to bring a post back from the dead, but this thread comes up at the top when trying to find info about fan mufflers.

I don't like to "mod" my parts, due to the PITA of getting a good clean look. I have a couple of good power supplies, one that I want to quiet is the OCZ gameXstream 700.

I can't find any ready-made mufflers any more. There were a few compaies making them in the 2003-2005 time frame. The Silverstone PSU Muffler from 2005 is not for sale anywhere and the only one I have been able to find is the new Lian Li one.

Head over to the post and poll in the power supply area, and tell me what you think.

After my earlier posts above (some years ago!) I was forced to concede that these "mufflers" are rarely worth it. The best thing is to buy a quiet power supply, and maybe replace other noisy components, too. My experience showed that it's simpler, quieter, and cooler to avoid creating the noise in the first place.

The ones you linked to (Lian Li) seem too hard, thin, and minimal in geometry to dampen sound at all. The one I used had some noticeable effect, but it used a rectilinear "S" shape, lined with dense foam, and backed with the mass of steel, to absorb sound and prevent reflections. The result was higher temperatures, which in turn required higher fan speeds...

Honestly, if you are wondering about this decision, simulate the effect using a couple layers of cardboard bent into the same shape as Lian Li and tape it on the case. Test it for an hour and see if you notice a difference. My guess is that it won't have much effect - at least not $30 worth of noise reduction. For $30, you could net the difference between a quiet PSU and selling your current one.

Fan mufflers?

Fan mufflers?

clarifications

They make them now! Would these work?

Re: They make them now! Would these work?

Re: They make them now! Would these work?