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Building a Dead Silent PC
Jouster writes "The folks over at HardCoreWare.net have finally lost it. They built a PC that's well over twenty times quieter than their comparison PC (40 dB versus 65). And it's no sluggard, either: P4 2.80 GHz, 7200 RPM hard drive and--get this!--an overclocked to the max GeForce4 Ti 4200! The only fan in the entire system is in the PSU."
Decibels is a logarithmic scale.
So 10db is 10x (power), 20db is 100x and so on.
This might seem like they are understating the case, but in general 10db is considered to sound like "a doubling in volume" so a difference of 40db is roughly 2 to the 4th or 16x.
Fiddle with a few db more and you can easily justify "20x quieter."
It's a logarithmic scale. The volume of the sound goes up ten times for every ten decibels. Here's some math and a comparison chart.
Radiant heat transfer is on the order of 10-100x less effective than convective cooling (like with a moving airflow). Radiant transfer varies as the fourth power of temperature, and does not turn significant until you get to temperatures that would a) fry any component you can name and b) give you a really good burn when you accidentally brush it with your leg.
So the window, apart from looking stupid, doesn't really hurt anything. : ) 'Cept the faraday cage.
Why yes, I AM a rocket scientist!
No, but heat kills bearings. So, the hard drive will probably be the first component to fail, especially with today's sensitive drives.
Another mid-term problem would be the electrolytic caps. They will dry up over time, which will introduce sporadic instability/reboots at first, and you'll be driven mad searching for the cause. Almost impossible to detect without special equipment, i.e. an ESR meter.
So, if you want a silent PC, you'd be better off buying cool components in the first place. It's just too much of a hassle (and expensive) trying to silently and reliably cool high power CPUs and graphics cards.
Did you know you can fertilize your lawn with used motor oil?
2,512 times quieter than the 65 dB machine:
10^3.1 = 1,259
10^6.5 = 3,162,277
3,162,277 / 1,259 = 2,512
No.
Heat exchangers want to maximize surface area, not mass. You are trying to present the maximum surface to the surrounding airflow, cooling by convection. More mass would simply be a thermal battery, storing heat on the processor. The thin heat sink fins actually remove heat from the processor by transferring it to the surrounding air.
Why yes, I AM a rocket scientist!
I'm not sure where this 20x quieter thing comes from, but generally. a 10dB increase in sound output is considered "twice as loud." Note that a 3dB increase is twice as much energy (well, 3.0something, but close enough). Similarly, -3dB is the "half power point."
Your physics teacher will tell you that 10 dB is a 10x difference in the intensity of a sound wave.
Your psychology teacher, or your friendly local audiophile, will tell you that a 10x difference in wave intensity is only a 2x difference in perceived loudness.
Most slashdotters, geeks that we are, payed more attention in our physics classes. As a result, I forgot about the perception issue until just now.
I am currently listening to 128 kbps mp3s on a $25 pair of headphones. Whether or not I am an audiophile is left as a exercise to the reader.
A legparnasom tele van angolnaval.
I'd accept a few degrees hotter silicon for the huge reliability boost of getting rid of the fans on the processor and graphics card (MTBF circa 15,000 hours in the real world contrary to their b.s. specs, divided by two since there are two of the little bastards). Your remaining fan in the PSU case needs a fan rotation alarm on it, and if unattended, some kind of thermal shut-off or redundant fan. One nice trick for quiet fans is to use one much bigger than you need and then run it at a slower speed. Another tip is to mount the disk drive and fans on Sorbothane standoffs, and maybe stick a couple of slabs of Sorbothane on the walls of the PC case. One quibble with the article -- for best cooling, you want as small a case as possible, not as big as possible. The objective should be to maximize the velocity of the airflow over the heatsinks, and you do this by constricting the space around them. One innovative way this has been done is through the use of engineering foams like E-PAC which allows the designer to create engineered air ducting which forces the airflow over the parts where it is needed. Some other people have asked why the PSU fan is necessary -- having just gone through CE and UL testing on one of my products, you can't imagine the kind of pain the test lab would make you go through if you took the PSU fan out of the PSU case. It's only a practical proposal for a major corporation with a lot of money and time to throw at it.
The slot loading "original" iMac (aka the gum drop) had(has) no fans, quite hardware, and vents on the top of the case. I don't quite know if Apple's eMacs and LCD iMacs have a similar set up, however I'd bet that they have fans.
2 002_480.html Honestly, I've never seen a bigger heat sink within a consumer PC. One could fry 10 strips of bacon on that beast.
Nevertheless, Apple still strives to build fairly quiet boxes when ever possible. I mean hey, look at the fan to heat sink ratio in this box: http://www.apple.com/hardware/gallery/pmg4_august
"Things are more moderner than before- bigger, and yet smaller- it's computers-- San Dimas High School football RULES!"
Actually, dB is a logarithmic scale, so 0dB is not actually *zero* like you assume, as 10^0 == 1. You could have something that was at -1dB which would be quieter than that. On this scale, "complete silence" really doesn't exist. It all depends on how sensitive your measuring device is.
--
grep "xercist"
The guys at Silent PC Review would scoff at the "hardcoreness" of hardcoreware.net when it comes to silencing PCs. After being on their mailing list for a year, I can tell you that they're waaay ahead of these guys in every aspect of PC silencing, many of which I've implemented myself.
I've been using an acoustically sealed case from Noise Control. I really can't hear my PC anymore.
I also use one of Noise Control's modified Enermax PSUs and a Silverado CPU cooler. That's all I did to my PC to make it quiet, everything else is stock. A quiet case seems to be the most logical (and least expensive) first step if you ask me. If you can still hear any of your components after you've put them behind 2 cm of noise blocking fluffy stuff, you can start replacing noisy those one by one until the noise stops.
Noise Control now has their own fan control circuitry and new modified PSUs come with it built-in. Also, they have hard drive cages that catch vibrations before they reach your case. With all of that equipment it should be easy to quiet any PC.
mod this one down plz!!!
+10db is twice as loud to the human ear!
So the 65 db down to 40 db should be something like 5-6 times less loud to the human ear!
Its the energy that is 10 times as big when you go up 10db!
Example:
A 10W stereo plays x db
A similar stereo with 100W plays x + 10 db
A similar stereo with 1000W plays x + 20 db
There's one more aspect to that. When you have very thin, long fins, like the Zalman heatsinks do, the thermal conductivity is too low for the heat to be transfered all the way to the tips. From what I can see on the photos, these heatsinks are not as efficient as they could be. IMHO the optimal heatsink would have a tree-like structure, whith thick 'stems' conducting the heat to many thin, but reasonably short 'leaves'. The Arkua coolers seem to somewhat follow this approach.
Did you know you can fertilize your lawn with used motor oil?
Sound level is how loud a sound is to human ears. It can be measured in dB and an increase of 10 dB sounds ten times louder to human ears.
Sound intensity measures the energy of the sound, often in W/m^2. (Watts per metre squared.) If you multiply the sound intensity by the face area of your eardrum, you'll get the number of Joules per second (W = J/s) that your ear is perceiving. This scale is linear with human hearing perception, so double the intensity means it sounds twice is loud.
The Equation:
B = 10log(I/Io)
B = sound level in dB
I = sound intensity in W/m^2
Io = sound floor of human hearing, Io = 1x10^-12 W/m^2
So, doing the math, 40dB = 1.0 x 10^-8 W/m^2.
And 31 dB = 1.26x10^-9 dB
So therefore, 40 dB is 7.94 times more intense, and therefore 7.94 times louder to human ears.
(7.94 = 1.0 x 10^-8 / 1.26x10^-9 )
Note: the previous poster's comment about one being 2,512 times quieter than the other was for different values, and this information does not override that person's (correct) calculation.
Thank you, and have a nice day :-)