inline fan sounds like a turbo jet engine vroom vroom muffler?help!

[floydfanx6]

hey guys i have a 440 cfm inline and its pretty damn loud. its not the noise of the fan actually,,its the air flow coming out of the duct (the output) like a swooshing noise but very loud
i have a carbon scrubber on the output end it helps,,but not enough
my question is would a duct muffler help a lot if i buy 1 along with the scrubber?
I dont know much about duct mufflers,but dont they reduce the noise of the fan,,not the actual air flow noise??
what can i do guys,,i baught a fan controller as well,,,but i want it to be quieter,,your thoughts,,pleaseeeee help this jet turbo engine stop taking off!! or my girlfreind will leave me,lol

 

[polly1123]

Check out these posting from another member that helped me along. Its the DIY stuff that I love about growing indoors. Cheers Mate and best of luck.

http://www.icmag.com/ic/showthread.php?t=40637

 

[floydfanx6]

yes id rather buy 1,,but my question isnt answered he said that he hears no noise coming out of the duct by air,,,,will i hear the big swooshing sound? the air exiting,,like i said its not the fan noise,,its the air exiting the duct i need to stop some how
help!!!! anyone pleasee

 

[PonicalChillin]

i've got a 8 Can Fan MAX sitting on top of a Can Filter 100.

Before adding a few feet of ducting and a 8" CF Muffler the wooshing air noise was loud..the duct muffler has SIGNIFICANTLY reduced the noise.

I highly recommend the duct muffler for anyone trying to cut out some sound. They are large however in size..so plan accordingly.

edit - the noise is coming from the air moving across the edge of the fan.. or edge of ducting, etc.

 

[floydfanx6]

thank u so much ponical
right now i have about 1.5 foot of duct before the scruber,,is that enough? should i connect the scrubber or the duct muffler to the output first this better work or my girlfreind is leaving me LOL

 

[floydfanx6]

also i see 2 type of mufflers the fantech,,which has rubber on it and is more expensive,,and the suncourt one which 1 is better,,i think my girlfreind is packing already lol

 

[Loblolly1]

I'd just get a dimmer switch for the fan - you're still going to hear moving air, but it won't be nearly as loud as the thing running full blast, and you won't have to modify your existing setup beyond plugging the fan into a dimmer switch.

Edit: your fan is already on a controller

 

[floydfanx6]

its not yet,,but i have baught 1 already,,,im sure i can cut the fan speed by half,,and reduce the noise in half,,and still have nice temps,,but whats the deal with the duct mufflers these 2 options
http://cgi.ebay.com/6-Inch-Duct-Muffler_W0QQitemZ270313085492QQcmdZViewItemQQptZLH_DefaultDomain_0?hash=item270313085492&_trksid=p3286.m20.l1116
or
http://cgi.ebay.com/Fantech-Duct-Silencer-for-6-Duct-LD6-LD-6_W0QQitemZ220126566739QQcmdZViewItemQQptZLH_DefaultDomain_0?hash=item220126566739&_trksid=p3286.m20.l1116

will either of these 2 help with the scrubber?
my setup is as follows, cool tube open on 1 end -->duct-->fan-->duct--->scrubber
i suck air through the tube out the scrubber which is in my living room,,the scrubber is about 1.5 foot from the fan

 

[moses224]

i use dimmer switches they work great
http://webtronics.stores.yahoo.net/ensavat.html
http://www.bghydro.com/BGH/itemdesc.asp?ic=AFAFSC&eq=&Tp=

many more out there

 

[Philosophelon]

Short answer for ya --

Yes, they make a big difference.

I've purchased Suncourt duct mufflers (work well) and I've made my own (work better, but they are larger).

If you want maximum noise reduction, use a muffler and a rheostat (fan speed control) on your fan.

 

[SuperConductor]

Insulated ducting is the first thing you should do as it's the most cost effective (as long as you don't need loads anyway) and probably cuts the noise in half.

 

[messn'n'gommin']

You didn't say what size your vent is, so I am assuming it is a 6" tube. I found this at an A/V site that had the pic as part of sound damping system for a basement room used as a home theater. It allowed air movement into and out of the room and still maintained most of the room's damping qualities.



Finding a 6" to 12" reducer may be a bit problematic, so you might have to scale down a bit (say, 6" to 8" reducer, maybe even adding a 8" to 10" reducer to that). But, I also echo SuperConductor's and others advice, a speed-controller, and flex duct with a relatively long run and, at least, a couple of 90 degree bends, will go a long way towards damping most of the sound. Although, these techniques will add to the resistance the fan will have to overcome, several methods together are probably better than just one or two.

Hope this helps a bit.

Namaste, mess

 

[guest 77721]

hey guys i have a 440 cfm inline and its pretty damn loud. its not the noise of the fan actually,,its the air flow coming out of the duct (the output) like a swooshing noise but very loud
i have a carbon scrubber on the output end it helps,,but not enough
my question is would a duct muffler help a lot if i buy 1 along with the scrubber?
I dont know much about duct mufflers,but dont they reduce the noise of the fan,,not the actual air flow noise??
what can i do guys,,i baught a fan controller as well,,,but i want it to be quieter,,your thoughts,,pleaseeeee help this jet turbo engine stop taking off!! or my girlfreind will leave me,lol

The air noise is from the air moving very fast though the duct and there's a lot of turbulence caused by the accordion pleats of flexible ducting.

To control the noise, the air speed has to be slowed down without reducing the air flow rate. The best way to do this is to increase the size of the ducting or duct into a large chamber before exhausting.

Let's say you have a 4" duct blowing at 440 CFM. The 4" duct will have an area of 0.09 sqft. Divide the CFM by the area to get the velocity. This works out to be 5045 ft/min or about 57 mph.

Here's a table of air flows and speeds so you can see how much of a difference the larger chamber makes.

Air Flow (cfm) Duct Air Speed (mph)
440............... 4"........ 57
440............... 6"........ 25
440............... 8"........ 14
440............. 10".......... 9
440............. 12".......... 6

Just get a big long cardboard box and stick your duct into the one end. Put a light fabric or a grill on the other end to create a tiny bit of back pressure.

If you've noticed any ventilation system uses grills on the exhausts. This is to straighten the air and reduce turbulence so the exhaust air is quiet.

 

[Work2much]

Great info Red. I'm going to have to spend more cash now to upsize my ducting now.

Are you sure you aren't a secret agent from Home Depot?

 

[guest 77721]

actually I'm in league with Canadian Tire and the makers of Duct Tape...

 

[ThaMagnificent]

Red: Great Info