Fans and what the specs mean. 2

[GoLdFiNgeR]

Hi all, im looking at fans and wondering the following:

What does cfm mean? im sure its something to do with air flow, higher number means more air circulation?

What does dba mean? i know it has to do with the noice level, and that a higher number means more noice,

should i care what these stand for, or just konw what they mean?

thanks
will

 

[rudeboyjeff]

CFM is cubic feet per minute. The higher the number, the better air flow it has. The dba, i forget, i think it stands for decibel something, but the higher the number, the louder it is.

Jeff

 

[GoLdFiNgeR]

cool thats what i figured, thanks

 

[Eguy]

Will;

dBA is the abbreviation for decibels.
Some points of reference are:

0 The softest sound a person can hear with normal hearing
10 normal breathing
20 whispering at 5 feet
30 soft whisper
50 rainfall
60 normal conversation
110 shouting in ear
120 thunder

Ed

Please let me know if the suggestion(s) I provide are helpful to you.
Sometimes you're the windshield... Sometimes you're the bug.

 

[GoLdFiNgeR]

awesome eguy, that actually helps alot, i was wondering about how loud 35 dba is,

gratis
will

 

[paparazi]

Eguy, how can nothing be something?
I do like your chart though, it is a good reference.
Goldfinger, 35db is just starting to get anoying! not load but irritating! about normal stock fan noise on a big 2gig heatsink.
One consideration though is the type of noise!!
35db produced by a 60mm fan is often high pitched and an unpleasant sound, where as 35db produced by an 80mm fan is a much lower pitch and easier on the ear!
A great idea to reduce noise are the 60-80mm adapters that allow the use of a quieter but equally powerful 80mm fan on the CPU heatsink. Martin
Just trying to help, sometimes falling short, I am only human after all.

 

[edfair]

You could try "decibel measurement" for a google search and get the set. Ed Fair
unixstuff@juno.com
Any advice I give is my best judgement based on my interpretation of the facts you supply. Help increase my knowledge by providing some feedback, good or bad, on any advice I have given.

 

[Stretchy]

Generally speaking (for each size of fan) the higher the cfm the higher the dba.
i.e a 60mm fan with a CFM of 35 (powerful) will be much noisier than one with CFM of 25.
an 80mm with a CFM of 35 will be much quieter than its 60mm alternative. _______________
Stretchy [Pipe]

 

[GoLdFiNgeR]

ok guys thanks, i just got 2 80 mm fans with 39 CFM @ 32 dBA
it looks good to me,

thanks for your input
will

 

[ceh4702]

Enermax makes adjustable fans that can be turned down to make less noise. They turn at over 6,000 RPM so they get a little noisy. Ideally larger fans should move more air with less noise. Making quiet fans is probably a tricky science. A lot of the first computer designers working on the internet technology were accoustical engineers. If you do not like my post feel free to point out your opinion or my errors.