Fans question

With the summer in full swing, and temperatures getting insanely hot, i was thinking of upgrading my fans to better quality ones. But i have 2 questions:

1. Right now i've looked briefly at some fans and i've seen the Delta 80mm fan which has a very impressive 80CFM, but the downside is 52dBA. Do you think it'd be worth the noise? I'm not really that bothered about noise tbh, but if it's really really loud then obviously it'd bother me a bit, or maybe you guys could recommend me some others?

2. If i were to only get one fan, which would be the more useful position, intake or exhaust?

#2 depends on your current setup. Want me to guess?

A point for you to consider.

Required airflow 80cfm:
Your choice of fan (single), sound output 52dB.

Alternative 40fcm fan, sound output 33dB.
2 fans required to achieve 80cfm so the sound output is doubled, but what's the answer?

The answer is not 66dB, it's about 36dB. The decibel scale is base 10 logarithmic, so for double the sound output you add just over 3 to the number. That means that the single fan is about 32 times louder than using the 2 fans I've described.

High airflow noisy fans are a poor solution if you can fit multiple quiet fans to achieve the same result.

To achieve the required airflow both fans must be operating in the same way, ie both inlet or both exhaust, but having one of each will still achieve a much higher airflow than a single fan, and because there is less air resistance should be quieter than two inlet or two exhausts.

If you've got the space, 4 fans is an even better choice:
20fcm fan, sound output 18dB. 4 fans required to achieve 80cfm so the total sound output is about 27dB - the single fan is about 250 times noisier.

Quote:

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Originally Posted by lynx

A point for you to consider.

Required airflow 80cfm:
Your choice of fan (single), sound output 52dB.

Alternative 40fcm fan, sound output 33dB.
2 fans required to achieve 80cfm so the sound output is doubled, but what's the answer?

The answer is not 66dB, it's about 36dB. The decibel scale is base 10 logarithmic, so for double the sound output you add just over 3 to the number. That means that the single fan is about 32 times louder than using the 2 fans I've described.

High airflow noisy fans are a poor solution if you can fit multiple quiet fans to achieve the same result.

To achieve the required airflow both fans must be operating in the same way, ie both inlet or both exhaust, but having one of each will still achieve a much higher airflow than a single fan, and because there is less air resistance should be quieter than two inlet or two exhausts.

If you've got the space, 4 fans is an even better choice:
20fcm fan, sound output 18dB. 4 fans required to achieve 80cfm so the total sound output is about 27dB - the single fan is about 250 times noisier.

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Good info. I previously just thought th dBA adds depending on # of fans.:)

If your case will allow for larger fans then use the largest that will fit and use slow speed fans. Slower spinning larger fans move more air but are quieter.

Thanks for all the info lynx. I've seen a YS-Tech 80mm that has 45CFM at 34.5dBA, plus it's about half the price of the other one.

Having relatively equal intake and exhaust is also important to sound output (a struggling fan will make more noise than a stable one). Because of this you need to take into account the power supply exhaust fan as well as your added fans.

also make sure there is good air flow, from intake to exhaust and around your componants, Tiddy up all the clutter of wires

Yeah, i'm also buying a cable sleeving kit and new fan gaurds to replace the old ones i cut out.

52dB is too loud!
Do you have to use 80mm fans? Most 120mm fans are under 30db, and move over 50CFM of air.