air flow noise problem

[shogun]

hi everyone just installed my 6ins carbon filter and 4ins air intake..the problem i have isnt with the noise of the fans but air flow noise..i have bought a temp controller but when temp in the growroom gets too high both fans kick in full power and air flow noise is too much is there a way i can reduce the air flow noise..thanx shogun..

 

[Brother Bear]

insulated ducting
duct muffler

you have a fan on your intake ??
make your hole a bit bigger, while maintaining neg air pressure
and get rid of the intake fan

 

[shogun]

duct muffler

duct muffler

hi is there a way too build a duct muffler and get rid of my intake and just have a passive intake??

 

[B.Grant]

Muffler - http://www.icmag.com/ic/showthread.php?t=42646

 

[Phillthy]

Part of the issue is you have a 6 inch fan and only a 4 inch intake. This is causing a lot of turbulence. Your intake should be almost twice your exhaust.

 

[DiscoBiscuit]

if you have a brush type motor, get a router speed controller from harborfreight.com. you can slow those fans down and they'll be less noisy.

 

[FreezerBoy]

Nothing you do will silence a running inline fan. It can't be done. You can quiet it, mask it, pin the noise on something else but, the noise will ALWAYS be there in the room. The only way to remove the noise from the room is to remove the fan. If you can't do that, remove the people and lock the door.

Mufflers, speed controls, insulated ducting and fan isolation boxes work wonders but, they're not enough if people are allowed in the same room. For that you'll need aquariums, computer servers, box fans ... something to mask the noise or take the blame. My axial fan is clearly audible but, once people trace it back to a beat up old freezer, they lose interest. The freezer becomes silent and invisible.

 

[BeeBee]

Phillthy, you are completely wrong. Having twice as much intake as exhaust leads to positive pressure, which leads to smell leakage.
The best way to control air-flow noise is with insulated flexible ducting. Attach the filter to the exhaust fan with a short (six inch) length of duct, and then have at least 8 feet of duct between the fan and the exhaust discharge. Have at least 8 feet of insulated duct on either side of the intake fan.
Also, if you put speed controllers on both fans, you can dial in a constant, lower setting that will keep your temperatures where you want them. That way, both fans won't suddenly go from off (or idle) to full on.

 

[j.guit.err]

Well I'm going to disagree with you BeeBee. My intake is twice my exhaust and I get no smell leakage. Also, that is the normal formula that everyone seems to use. Not ragging on you, it's just my experience and seems to be the prevailing knowledge on this board at least.

 

[FreezerBoy]

Danger, Will Robinson! Put that saw down for a minute.

Phillthy, you are completely wrong. Having twice as much intake as exhaust leads to positive pressure

Only if the intakes are powered. You can suck air in faster than you suck it out(positive pressure) but not the other way around. With passive intakes, it sucks what it needs and the increased airflow through the cab creates negative pressure just like an airplane wing or a curveball.

Double intakes is SOP for cab growing. Some use 3X, some use 4X. The best way to avoid generating positive pressure is to avoid the use of positive pressure generators such as intake fans.

 

[BeeBee]

OK--sorry. But I was responding to this thread, and in the original post, there seems to be no question that there is active intake and exhaust--two fans. Of course you can't have positive pressure with no intake fan!
But really, in any situation, it is always possible to control the fans in such a way that you avoid positive pressure. And the advantages of active intake are huge, so powered intakes shouldn't be avoided, when they are needed.

 

[Entropic]

A simple fix for positive pressure with active intake fans is just to tape a piece of thicker paper over part of the fan (works well with PC fans), or some other sort of obstruction.

Not the best solution but will work in a pinch.

 

[4maggio]

What's so bad about intake fan?

What's so bad about intake fan?

insulated ducting
duct muffler

you have a fan on your intake ??
make your hole a bit bigger, while maintaining neg air pressure
and get rid of the intake fan

High BB.. why the advice to dump the intake fan? I too run pancake fans for intake, they seem to do OK... am I missing something?

EDIT::Sorry, I should have read further on..

 

[greenisgold]

High BB.. why the advice to dump the intake fan? I too run pancake fans for intake, they seem to do OK... am I missing something?

EDIT::Sorry, I should have read further on..

If you dump the intake fan then you get rid of half the noise. Just open up the intake whole bigger and let the exhaust fan do all the work. I think that is what he meant?