[zapper7]

I have a Mackie pro amp for the subwoofers I have and would like to know where and what to buy for a quieter fan. The fan is an 80mm size.
THanks

[Russell Dawkins]

I would contact Mackie - they're really helpful. You might wind up with something like one of these:

http://www.newegg.com/Product/ProductList.aspx?Submit=Suggested&Description=35-186

Simply ask them what the specs are on their fan - voltage, CFM needed, etc. then shop for one.

[Audiovista]

80mm fans are typically not very quiet as they are designed to move a lot of air.

Sometimes I use higher voltage fan and run it at reduced speed (220VAC fan on standard 120V, 24VDC fan on 12V, etc.). That reduces available CFM considerably so, when critical, I simply insert a small resistor in series to add 2-4V drop and again reduce fan speed but not as much. And fan life goes up.

[BradJudy]

80mm fans are typically not very quiet as they are designed to move a lot of air.

Huh??  There are lots of 80mm computer fans designed to be super quiet rather than push lots of air.

I'd recommend checking out one of these, they should all be inaudible from more than a couple feet away:

http://www.newegg.com/Product/Product.aspx?Item=N82E16835185035
http://www.newegg.com/Product/Product.aspx?Item=N82E16835118206
http://www.newegg.com/Product/Product.aspx?Item=N82E16811999602

[NewBuyer]

The standard Antec 80mm fan, running at 5 volts, is very quiet indeed. If you can tap 5v  in your amp, this would be the way to go (it works great in computers this way).

[ctviggen]

You have to be careful with replacement fans.  I replaced a fan in my QSC amp (which had an incredibly loud fan), and the fan I replaced it with moved quite a bit less air (which may have led to the demise of the amp, although I doubt it since I only used it to run my subs).  Also, it was an 80mm fan; I think it was 60mm or even smaller. 

[Audiovista]

80mm fans are typically not very quiet as they are designed to move a lot of air.

Huh??  There are lots of 80mm computer fans designed to be super quiet rather than push lots of air.

Right, but they move less air than decent 40mm (relatively quiet 35-40dB) fan.... I guess my point (that was missed by BJ) was that there is a trade off between air flow and noise and one should look for an acceptable compromise.

[BradJudy]

Your point isn't missed at all, but most 40mm fans put out about 10CFM at 25-30dbA, whereas the 80mm fans I linked to put out about 24CFM at less than 25dbA. 

In general, the larger the fan, the better the ratio between airflow and noise. 

What 40mm fans are you using that manage to beat this general rule of thumb for airflow/noise ratio?

[zapper7]

Thanks guys, I will look into these options, seems like Newegg is the place.

[dave_c]

I've great results with the SilenX fans as well:

http://www.frozencpu.com/products/5354/fan-265/SilenX_80x80x25mm_-_14dBA_-_32CFM_iXtrema_Pro_Fan_IXP-54-14.html?tl=g36c15s58
http://www.frozencpu.com/products/5227/fan-256/SilenX_80x80x25mm_-_9dBA_-_20CFM_iXtrema_Pro_Fan_IXP-54-09.html?tl=g36c15s58

FrozenCPU and Newegg have both been great to work with.  If you live in California you'll have to pay tax at newegg if that makes any difference.

[Audiovista]

Zapper, glad we could help.

Brad, your rule of thumb is good, but there are exceptions, even without going to exotic fans from Papst or Delta (mucho dinero). For instance, Sunon has a 40x40x20mm fan, 6.3CFM at 19dBA (KD0504PKB3). Four fans would have outside size same as 80mm fan (with much smaller active area than 80mm fan) and the airflow would be 25.2CFM at 25dB (I think you get +3dB for doubling the number of noise sources, but not 100% sure), roughly the same as 80mm fan. Dunno why would anyone use 4 fans  , other than for comparison 

In the end, those numbers make very little sense for practical application as both, the actual noise and airflow depend on the back pressure and loading curve of a specific fan.

It seems that this thread has done its job, so best wishes to all and see ya around!