Fans' rated dBA not standardized?

[TownRanger]

Hi, I'm a n00b in case modding. I don't have a dremel or any modder toy. I noticed a little something about how the dBAs of fans are measured.

Getting to it, the other day I got a 120mm rated 19dBA. I installed it at the back of my case as an exhaust fan with some silicon sound dampening screws. I also connected it to the fanbus to decrease its rev to reduce noise. I presumed that will work like heaven for me. And when I switch it to the maximum, there will be some, but not annoying, noticeable sounds from the fan.

Yesterday I got a 80mm one rated 27dBA. My first impression is, it's "loud and clear!" But a strange thing happened. I installed it on the side panel and also I made its 4pin connector to my fanbus. I switched it to max but it does not sound as much as the 19dBA one does!

I then have a browse through the paperbox and the websites of the fans. The criteria of measuring the dBAs are actually a whole lot different. The manufacturer of the 120mm one specifies that the noise is measure from a distance of 1m away from it; while the 80mm one does not tell how they measure its noise.

I start to think, if it is up to individual manufacturers to decide HOW and HOW FAR AWAY they are going to measure their products' dBA, that will create an unfair environment. It's also very hard for us to believe the data written on the package or in the website. There's always no fair comparison if fan noises are to be measured in anyway any manufacturer likes.

So if we want less noise by choosing a fan with a less rated dBA, then there's no guarantee it'd be up to our expectation.

 

[blendingnoise]

I got this answer while asking a different question about quiet fans

Because they're the only brand of fans that are reliably tested from a distance of 1ft in open air.

All those other manufacturers either test from 3m (like Silenx), add lots of fan blades (like Aerocool - Note: This increases airflow, but decreases static pressure) or at a lower voltage etc.

The only other "good" (and by good, I mean, at 12v from 1ft) manufacturers I've come across are Silverstone, Panasonic, Delta and Sanyo-Denki (and POSSIBLY Noctua).

Most case modders don't understand how fan noise levels work, so the manufacturers chrome the fan, add LED's and screw the testing, while their customers are so happy their shit glows to care.

Industrial, professional fans (panasonic, Delta, SD etc.) pretty much have to have similar testing standards.


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And yeah, 3.50$ is a GREAT selling point... 2.50$ if you get them in lots of 100 from a supplier.


**EDIT** but those Aerocools you linked to are actually OK... About on par with the Yates IMO.

edit: I was asking about yate loons 120mm fans

 

[Bbq]

My guess is you got a SilenX 19db 200,000 cfm fan?

Those are measured by 19db being at the lowest operating voltage, and the cfm rating, at 12v. At 12v, they're about 30-35+ db.

Maybe it's perception? Your original fan was mounted with silicon grommets, and it had the sidepanel to dampen it, if it was right next to you. The new one, doesn't.

 

[Mohonri]

To answer the title of the thread, "No". There is only one portion of the computer parts market that is less honest than the PSU industry, and it's the computer fan industry. Don't believe anything you read from the manufacturer about a fan's specs. Instead, I would recommend you look at silentpcreview go find out what fans are actually quiet. For example, Yate-Loon has a good reputation.

 

[Deejay3d]

My Aerocool 120mm is near-silent @ 1700rpm and moves quite a bit of air. Stay away from AC Ryan fans if silence is what you want. Can you say "jet-engine"?

 

[TTPete]

Decibels are not a good way of measuring how loud something is but more for sound pressure level. Also, different measuring techniques are used when using decibels. Also, one fan can be loud to one person and not loud to another. So If I think that a particular fan is loud, I would be like, thats not 17dBA its more like 21 while if someone else thinks that the fan is actually quiet will say, thats about 17dBA. In reality, decibel rating is exponential.

On the decibel scale, the smallest audible sound (near total silence) is 0 dB. A sound 10 times more powerful is 10 dB. A sound 100 times more powerful than near total silence is 20 dB. A sound 1,000 times more powerful than near total silence is 30 dB. -How stuff works

A better way for manufacturers to measure sound is sones. Here... Wiki will explain better than I...