Searching for an Ultra Quiet Air Circulating Fan

[Earthling]

Hiya all

Things are progressing my end and have my first little seed punching up with three others close behind...

 

I've got most of the things sorted but having trouble finding an ultra quiet fan for air circulating and to breeze the plants about for stem strength.

 

I bought a $30 Kambrook Arctic 30cm Quiet Desktop Fan which is not quiet...its louder than my cheapass $12 Pedestal fan.

Can hear both through my air sealed solid core door...not quality...

 

I thought about a bunch of quiet PC fans controlled down to a quiet speed, but it seems a rather lot of stuffing around and a high cost for possible not a great amount of airflow

 

Is there something you guys/gals can recommend for me?

 

Google has not been my friend on this one...

[billygoat]

Hi Earthling...

 

I dont think you should be too worried about the noise from a circulating fan....

 

you will more than likely have a noiser fan in your inlet and exhaust fans... particularly if you are running a centrifugal fan with carbon filter for the exhaust.... a little noise is easier to disguise than the beautiful smell of ripening buds

[K-9]

The bigger the fan the more air it will move and compared to smaller fans they will also do so at much lower noise levels.  That rule applies to all fans so buy much, much bigger than you need and dial it back to sane levels.   My personal recommendation if you have the room and can afford it would be one of those massive industrial pedestal fans as they're made to last and will serve you far better than a few cheapies from woolies in the long run.

[Earthling]

Cheers for the replies Billy and K-9

I've got a 10" Westaflex boxed in and a large Phat Filter into rigid tubing and a muffler to come. I will be able to gear down the Westaflex to around 30-50% speed (once I get the controller) which from my understanding should bring it down to low to very low noise levels...so much so that I think the circulating fan will be the loudest thing!

Its hard to disguise the fan noise here as its a very quiet area that's not used much, apart from storage, so would look suss to leave the radio on...
 

 

K-9 I don't have that much room but I understand your logic I bought a HPM 300F Fan controller switch from Bunnings to test as a controller, however when connected up to a desktop fan it just created way to much hum...made it more audible the fan noise.

I will pursue the large and gear down.

 

Does anybody know if the tutorial on how to make a Fan Speed Controller in Cannaversity makes the fan create any humming noise?
 

[spider_b]

I got birds they go off their heads if anybody is around

 

problem solvered

 

[onemancrew]

Fish tanks are awesome at hiding humming noises...

[merl1n]

Hey Earthling,

You say you'll be using rigid ducting. That is not a good idea. Any vibration from the fan will be amplified in your ducting. This is due to it being rigid as sound vibration travels easier thru a solid. You'd be better off using a flexible ducting and even better still a flexible acoustic ducting. Most air conditioning wholesalers stock it.

Another idea is to make a box for your fan. A polystyrene fruit box with a lid filled with carpet underlay, wrapped around the fan, works a treat. Ive also heard of people using an old sleeping bag or blanket to wrap the fan in.

 

Merl1n

Edited June 10, 2014 by merl1n

[Earthling]

Good ideas Spider and Oneman, however as of the location birds, fish or any animals for that matter would not work...its basically a storeroom Plus animals in cages is not my thing...

 

 

merl1n that's what I'm finding re:noise travel. The plastic stops the noise exiting out the sides very well. But...the sound ends up coming out the end fairly loudly Hence I was thinking a muffler coupled with a Fan Controller would assist somewhat.

 

I would love to try out some acoustic ducting...may have to bite the bullet.

 

I have boxed in the actual fan yesterday and whilst it made a difference, to be honest not a great deal. Its boxed in 3/4" MDF and crammed with rockwool insulation. 

Edited June 10, 2014 by Earthling

[merl1n]

MDF is again a solid, hence the use of polystyrene foam box.

[Earthling]

merl1n, solid objects can be good and can be bad when it comes down to sound waves...Ive been looking into this for a couple of years in other areas.  Stopping sound travel comes down to absorption and decoupling...and creating less sound in the first place

 

Rock wool (fibreglass) has the a very high capacity of absorption, converting molecular air movement (sound) to heat (at a molecular level).
In my soundproof box I have rockwool absorbing sound between the fan and the MDF. The MDF is also 'decoupled' (not touching by a 'mechanical' attachment) the fan in any way.

 

I was googling yesterday and remember seeing a good video that showed the sound reduction from just putting the centrifugal fan into a large packing box. It looks like the box is absorbing the sound and probably deflecting the sound to the open ends. Where I feel my box has gone 'wrong' is that its simply not big enough. I created it only 20cm wide as that allows 1" of the fans both ends to protrude for attaching ducting. The sound still travels out each end. When the Phat filter is on the intake the sound from that end is minimal. The outlet is loud. By wrapping the ducting in rockwool should assist, however it still comes down to that roaring of wind out the exit. Will use a fan controller and try acoustic ducting and a muffler plus my solid pipe and see what combination works best.

 

Plus a foam box exhibits very baaaad fire proofing capabilities compared to rockwool.