How loud is 30 db?

[yiplong]

I have a OCZ StealthXstream 700W PSU that I think may be defective:
http://www.newegg.com/Product/Prod [...] -_-Product

OCZ's tech support
told me this thing is supposed to be 30 db at idle and that 30 db is almost inaudible unless I am closer than 2 feet to the unit.

So how loud exactly is 30 db? I sit with the computer in front of me at my feet, the distance from the PSU to my hear I would say is at least 4 feet. It sounds pretty audible to me.

ps: Has anyone dealt with OCZ RMA? How long do they take to ship a PSU back? I don't want my computer out for weeks or months.

[Mithrandir]

Hope this helps

[kmac]

I would be a bit sceptical about manufacturer claims of noise. Any measure of noise should also specify the distance from the source that the measurement was taken. Manufacturers don't usually include this information. So it could be 30dB at one foot or at 30 feet.

You need a well reviewed PSU from the likes of JohhnuGuru or http://www.silentpcreview.com/Recommended_PSUs to ensure your pSU really will be silent.

[yiplong]

Is there a way to turn on the PSU w/o going through the mobo? this way I can just listen to the PSU instead of every noise producing component in the case. With so many things potentially noisy, it may be unfair to just blame the PSU for it.

[Saracen]

How loud 30db is is, actually, something of a meaningless question because db always related to some reference point, and without knowing what that is and the basis of the calculation, you'll be making some large assumptions.

However, generally, in terms of sound, the reference point is the point at which we just start to hear anything, and that's 0 db. Exactly how loud other things are are therefore in relation to about the quietest thing you can hear, and while examples differ depending on where you get them, a typical illustration would be something like :-

0db - a mosquito at several feet distance
10bd - leaves rustling in the distance
20db - background noise in a TV studio
30db - a quiet bedroom at night
40db - a quiet library

and so on.

But a LOT depends on how you measure it. For instance, dbA generally refers to Sound Pressure using A weighting, which, broadly, is designed to weight the standard logarithmic values to the response curve of the typical human ear. But it isn't the only way to measure it.

It's a bit like asking the top speed of a car and being told 20,000.

Well, 20,000 what?

If you were told 130, you might assume it was MPH, but you could be wrong and it could be KPH. So is 20,000 mm per hour, or mm per second, or furlongs per 17.4 minutes?

So I would assume the impression from a sound level of "30db" is that it's supposed to be a murmur, and not much more. The only way to be sure will be to listen to one.

[Pob255]

Saracen has put it quite neatly there, I'll expand on it a little.
The big problem is 0 db is the "egde" of human hearing, to use mikes car annology, it would be like all cars top speeds where measured in multiples of human.
ie this car is 20x fast than a man.
Fatsser than a man doing what? walking? Crawling? Running?
Which man? is that 20x faster than the world 100m record holder going flat out, or 20x faster then me trying to do 100m after a heavy meal?

It's a bit like calling a fan quiet, there is no fixed numerical value to "quiet"

[GoNz0]

Is there a way to turn on the PSU w/o going through the mobo? this way I can just listen to the PSU instead of every noise producing component in the case. With so many things potentially noisy, it may be unfair to just blame the PSU for it.

google how to test a psu, u jump a green wire to a black one.

[Steve]

google how to test a psu, u jump a green wire to a black one.

Although I should warn that you shouldn't really fire up a PSU like that without a load on it. However, I doubt a decent PSU would have an issue with it, and I've "jump started" a few PSUs without a load and never done one any harm (that I know of).

[yiplong]

I would be a bit sceptical about manufacturer claims of noise. Any measure of noise should also specify the distance from the source that the measurement was taken. Manufacturers don't usually include this information. So it could be 30dB at one foot or at 30 feet.

You need a well reviewed PSU from the likes of JohhnuGuru or http://www.silentpcreview.com/Recommended_PSUs to ensure your pSU really will be silent.

I did double check this with the OCZ technician and he told me the unit should be 28-30 db at a distance of 40-50 cm.

[yiplong]

To find out the relative loudness of the OCZ PSU, I swapped it with a Corsair 650W, and wow, my PC became silent. What a difference. I guess I should stayed with Corsair.