How do you use duct mufflers or silencers?

[noyd666]

that orta fix it

 

[s00thsayer]

The variac uses a transformer to reduce the voltage to the fan, making it run quiter at a lower speed. You can set the power on the dial anywhere from 0 volts to 130 volts. It will decrease air flow but so will a muffler to some extent. I have a 400 cfm fan hooked to a variac set to 60 volts (50% power) and it makes the fan move about 200 cfm of air but it is so quiet, much quieter than any 200 cfm centrifugal fan i've heard. I also use a charcoal filter on the duct, matched to the dialed back cfm...200. Here is a video I made starting at 60 volts, then increased to full speed at 120 volts so you can hear the difference in the noise level it makes.

http://tinypic.com/player.php?v=2cgeck4&s=6

A speedster or active air fan controller will also work but they use a rheostat instead of a transformer, and do not reduce voltage to the fan like a transformer. Instead it rapidly cycles the power on and off to the fan and will cause the fan to have a loud repetative hum like some dimmer switches on ceiling fans do and I've read that these are bad for fan motors but I don't know if that is true. The variac transformer on the other hand provides a steady continuous voltage that you set for smooth, hum-free operation. Read some reviews about the speedsters on greners and you'll see what I'm talking about. http://www.greners.com/duct-fan-speed-adjuster.html

Not sure if fan speed control is what you need but thought I would point it out as an option for noise reduction. Good luck.

 

[JimmyRow]

KitKat, not to step on your toes, just knew you had a good example. Just something to think about.nif you are gonna slow your fan down w/ a controller, your obviously loosing cfm. I'm personally using all I can get from my vortex fans, but a 6" booster fans still moves decent air and is virtually silent(in comparison)!

 

[s00thsayer]

a 6" booster fans still moves decent air and is virtually silent(in comparison)!

a booster fan is also a good idea but you already have a fan and in my experience the booster fans fail after about a year and are money wasted in the long run. centrifugal fans with permanently lubricated sealed bearings are the way to go.

 

[sweetestsin420]

1

 

[s00thsayer]

http://botanical.com/hydro/air/calculating_fan_requirements.html

You need to exchange your air at a minimum of 1 time every 3 mintutes. My setup exchanges all the air in the grow area about 1.5 times every minute and cools a 600 watt hood and a 400 watt hood and passes through a carbon filter using a fan moving about 200 cfm of air. 7x2x7 comes to just under 100 cubic feet so a 450cfm fan would exchange the air 4.5 times a minute, 225 cfm would exchange it 2.25 times a minute. I think you would be fine dialing down your fan speed but it depends on your ambient temps. The site above has some good formulas for calculating that stuff so you would know for sure. I think you could get by ok with 2 lights in that area if needed.

 

[JimmyRow]

Kit kats design is how they phresh engineered the system, and that how all of my buddies up here have theirs set up. And it works. Not silent but much better.

My booster fans blows @ 190 cfm. And I spent $10/each on em. Craigslist. Kinda depends on the noise is a pain in the ass or safety hazard. But I agree about centrifugal fans being the way to go. I couldn't pass up the deal I got. They are on the shelf, I'm running three fans now, a 4", 6", & 8". That shits loud!

Good luck.

 

[LEX-UK]

Always get a bigger fan than u need and run it on a dimmer.. Insulated duct & abit of soft insulate wrapped round fan or make a mdf box to house fan and pack it out with rock wool slabs.. We live in very close quarters here and this works a charm.

 

[sweetestsin420]

1

 

[Hammerhead]

OK where are we lol... get a in line fan appropriate size for the area you are using it in. Make sure it can be used with a speed controller. I just bought another 8" in line that can be used with a controller even though Im not going to use it for that... This will take care of your load fan..I have a speed controller it will reduce the noise for sure it will also decrease yuor CFM while doing that.. I bought this one..

http://www.amazon.com/gp/product/B004YXDR22/ref=oh_details_o03_s00_i00

Can be used with this

http://www.amazon.com/SE-Electronic-Stepless-Speed-Controller/dp/B000HQAVNI/ref=pd_bxgy_lg_img_y


I have never used a muffler before. I have read they work... I have seen prople use bungee cords to hang the fan to prevent rattling/vibration..

 

[sweetestsin420]

1

 

[Hammerhead]

Im pretty sure you can as long as your fan is a centrifugal fan it will work. CAP makes there own version of the speed controller. Some insulation covering the fan then mount it in such a way that the bungee cords hold it without anything touching the fan.. That booster blower is not good enough to use with a scrubber. Those are use to help increase the CFM on long runs of duct work. Thats t=not the right kind of fan for scrubbers or for intake/exhaust fans.. The one I listed is the right kind just get the right size in your case a 4" is what you want.

 

[noyd666]

i bought one 8'' booster for a lil xtra air when needed, brings in plenty, but soon as you put a filter over end they get out of shape, vibrate, air turbulance, .

 

[Kit Kat]

You could also get a variac controller as s00thsayer posted and then the fan type does not matter at all - you can step down any fan quietly. Here's a video someone posted on another site showing the difference between the 'Speedster' style controllers, and a variac:

http://www.youtube.com/watch?v=ABF8YhWGi60&feature=youtu.be

i use a variac variable transformer to quiet my centrifugal duct fan. it cut the noise down significantly in my setup. variable transformers don't make fans hum like the cheap speedster fan controllers.

http://www.amazon.com/Variac-Variable-Transformer-300va-Output/dp/B006NGI8VS

 

[sweetestsin420]

1

 

[Propagate]

from my experience the htg duct muffler for 4" is not a great product. The foam sound proofing protrudes into the 4" opening quite a bit and disrupts/partially blocks airflow. It does quiet that woosh sound, but it also reduces total cfm and makes my Can4HO fan work harder.

since then it has been removed. I will fab the next one.

 

[sweetestsin420]

1

 

[Propagate]

propagate how did you set yours up,on the intake or exhaust.

my idea would be to have the carbon filter acting as the intake "muffler",since they do quiet it down,then have the muffler on the exhaust,since it wont matter about cfm's at that point,cfms only matter for the intake of the fan


or i can just try the speed controller,insulated ducting,idk,thats the cool thing about growing,you gotta learn by experience.

my fan/filter setup is mounted to the ceiling(exhausting), and had the duct muffler 18" from the output of Can4HO fan.

A muffler on the intake no matter your setup, is imo, a waste of time.
If your intake air is wooshing, then add another intake to reduce velocity aka "woosh". fan works less hard when static pressure is reduced too!

 

[Propagate]

this is in a passive only intake, room.

couldn't edit post

 

[bicyclebenny]

Hey guys and girls, don't forget the do it yourself guides at the Link-o-rama: https://www.icmag.com/ic/showthread.php?t=40637
Ventilation 101 is always worth a look, too!