What dBa is too loud?

[oachalon]

just to tell you a 3db increase is twice as loud. Just ask any audio expert.

 

[fafnir]

yeah, 20db can get pretty loud sometimes, i can hear my neighbor's cat as the thing walks across concrete and so on

i run a zalman reserator and i can hear the pump

i hear cpu/mobo electrical noise; you know the sound of the caps discharging?

and something that really annoys me is a loose coil in a transformer; very high pitch and really loud, usually only me and the kids hear the thing, ~15000hz

mechanical clocks get REALLY LOUD when its quiet


_

 

[TheWesson]

just to tell you a 3db increase is twice as loud. Just ask any audio expert.

nooo ... really really ... 3db is approximately twice the sound energy ...

10db (one Bel) is ten times the sound energy.

Bels = log10(sound energy)

But we humans don't perceive sound and light on a linear scale. A room lit at night has thousands of times less light energy than daylight. (Daylight would be one 100-watt bulb per square meter of surface ... !!) Yet obviously a room with one 100-watt bulb in it looks fairly bright, even at night.

So ten times the sound energy is perceived as roughly twice as loud. If you work that out (log10(S) = log2(P)), it turns out that we experience approximately the cube root of the actual sound energy. (Maybe the same is true for light, I don't know. In that case, daylight would be perceived as about ten times as bright as a room at night.)

Alright, I'll google sound and dB and all that for you.

http://www.science.org.au/nova/072/072glo.htm

There you go.

the wesson

PS 0.3 Bels increase (3 dB) means 10 ^ 0.3 times as much energy. 10 ^ 0.3 = 1.995. But mapped to what is perceived, that would be 2 ^ 0.3 times as much perceived, hence 1.231 times the perceived loudness. In other words, noticeable. But no big deal.

 

[Tat]

Man I wish I could get the Delta with 42 dB then i can turn it down around 40 or under. But there is no more. I have TT Smartfan rite now and I hate it => the whiney sound I rather lound lound if u know wat i meant but not the high pitch sound. 35dB is not loud to me, so i must say 40 and under is koo. Well does any one know where I can get that Delta? Sidewinder has it no more .
Peace.

 

[TheWesson]

anyhow to answer the original question, I'd want to stay below 30 dB for any fan that was in a small bedroom. Where possible, use large fans (120mm or 80mm) in the machine, or multiple small fans running at low RPMs. For noise, it seems the important thing is to have the given CFM being moved through a large area of fannage, whether that's 2 80mm or one 120 or whatever.

of course you will want a heatsink that takes an 80 or a 92mm fan (Thermalright) instead of a heatsink that uses a 60 or 70mm fan. Trying to move the same CFM through a smaller area increases the noise level a lot!

The Zalman 7000 series are OK too (they use an adjustable 92mm fan). It's that or Thermalright I'd say. A good cheap Thermalright heatsink is the ALX-800 if you don't want to get fancy. Put a Panaflo L1A 80mm on it and you've got good cheap quiet cooling.

The heatpipe/tower style heatsinks are decent and usually take an 80mm fan, but are pretty spendy for the cooling you get and can represent a menace to your mobo if you move your computer.

the wesson

 

[Korndog]

But we humans don't perceive sound and light on a linear scale. A room lit at night has thousands of times less light energy than daylight. (Daylight would be one 100-watt bulb per square meter of surface ... !!) Yet obviously a room with one 100-watt bulb in it looks fairly bright, even at night.

good example man, you're a smart guy

edit:
yep, panaflo L1As are great.
a good combination i found was this :
6 panaflo L1A fans @ 21dba (two intake, two exhausts, two to replace psu fan)
and a ~25dba blower (like the cooler master) which puts out air at higher pressure, PERFECT for those dense finned thermalrights .
if u add'em all up it comes out to about 30.6 dbA. not too loud at all

 

[CrystalMethod]

Like a few people have stated previously. Noise level is relative to what you can personally tolerate. For example, I have 4 Delta 60mm 38's running full tilt 24/7, and I can sleep though them just fine. But, I'm a light sleeper, I wake up to any sort of other noise. Other people find that even one Delta will drive them nuts, let alone trying to sleep with one spinning. If quiet and cool are your goals, I'd suggest trying to fit the largest fan you can find with the most airflow under 30 - 35 Db, as you can find.

 

[enduro]

In my opinion. The Tornado and Deltas that I have are white noise. Instead on spending the money on a cd with ocean shores tracks and the sound of a river flowing, I have a constant track of the howling of a hurricane..... to aid me in a peaceful and quiet rest I'm thinking of selling cds online. " Having problems sleeping, hearing your mobo caps discharging , then get Enduro's relaxing cd filled with tracks of a howling hurricane mixed with the sounds of a Tasmanian devil in heat, experts have approved it's use by the public, so buy now for only 20.99"....... Maybe not

 

[Silversinksam]

I started a poll for you

http://www.ocforums.com/showthread.php?t=312610

 

[enduro]

Only two votes for over 50 dB. Come on people. I SAID COME ON PEOPLE. freaking deaf people. Oh, wait, I'm deaf too. Hearing aids on backorder, what's the world coming too

 

[TheWesson]

good example man, you're a smart guy

edit:
yep, panaflo L1As are great.
a good combination i found was this :
6 panaflo L1A fans @ 21dba (two intake, two exhausts, two to replace psu fan)
and a ~25dba blower (like the cooler master) which puts out air at higher pressure, PERFECT for those dense finned thermalrights .
if u add'em all up it comes out to about 30.6 dbA. not too loud at all

Gee thanks ... ! But one screwup: sunlight is actually 1000 watts per square meter total energy ... !

the wesson