So I thought I should revisit this thread, and give another update on the Wind Tunnel (
http://www.sunleaves.com/detail.asp?sku=SW604). I started this thread because I was looking for the quietest and best fan. I decided to try the Wind Tunnel 4 inch model. The feature that really sold me was the plastic case. I figured the plastic would dampen a lot of sound, and possible vibration. So here is what I think and what i did:
I put the fan on a speed controller so, to test it as if it was connected for use with a carbon filter (
http://www.4hydroponics.com/grow_room/speedster.asp). The fan it self is extremely quiet when ran at full speed. It seems to move a ton of air. It is rated at 200CFM. I connected it to flexible exhaust ducting on both ends, about 4 feet on both ends. When it is running at full speed the air exhausted from the ducting is louder than the fan it self. Soon as the fan is ran over a variable speed controller, there is a definite hum from the motor on the fan. The hum does not change in frequency at all when you adjust the speed on the speed controller, it does not seem to be variable with the speed of the fan. The frequency at which the fan hums seems to be louder than the noise from the exhaust for sure, when the speed of the fan is reduced. The fan it self has enough suction to not need to be ran at full speed for my application, but it seems to be quieter if it is ran at full speed, given that the exhaust air is less noticeable than a motor humming. The noise from the exhaust is less noticeable than the frequency at which the fan motor vibrates at when connected to a speed controller.
I hope this is a better description of my observations. I have nothing to compare this to, but I think that I will soon test a fan from
http://www.hvacquick.com/spfnconfig.php?fm=td , these fans seem to still be getting the best results.
I would like to get some feedback from other people that use the Speedster for controlling fan speed, do you get a hum from your fan motor?
Desert Fox has this thread going,
https://www.rollitup.org/grow-room-design-setup/202808-s-p-mixvent-speed-controler.html