Sound proofing

[Monkey Allen]

Has anyone ever tried using soundproofing clips and channels? They're supposed to be the best for sound deadening, but I wanted to see if anyone can confirm their effectiveness before I spend more money.

Ive already tried a whole variety of other soundproofing methods and materials, such as roxul, foam, carpet, bass traps, dynamat, eggcrate, etc.; however, all of those only muffle high frequencies. I'm trying to eliminate the low frequency drone produced by my exhaust fans. The best I was able to achieve was a 10db reduction, which is better than nothing, but still far from ideal for my situation.

I'm aware of fan speed reducers, but I have my fans hooked up to automated vent controllers, which don't allow me to use fan speed reducers. Can't compromise on that either.

Thanks in advance for the suggestions everyone!

[DW2]

Howdy Monkey Allen,
You can reduce some of the fan noise by reducing the transmission of the vibration of the fan to it's mounting or support structure by using 'dampers' or spring isolators. I have a 'low tech' fan mount (for the air circulation fans), they sit on a piece of corrugated cardboard held on to a block of foam rubber with duct tape. If You have 'inline' fans, a suspension system, that is flexible, could be made from elastic 'bungee' cords or something similar. Hard mounting to walls and other surfaces can amplify the vibrations, just like the body of a guitar or a violin does for the vibrations of their strings. The noise produced by the fans can be reduced by slowing down the velocity of the air by increasing the duct size. The faster that the air moves thru the ducting, the more friction and turbulence it will have, producing more sound. By going to a larger diameter of duct, the flow velocity is reduced (but not the amount (CFM)), and reduces the turbulence and the noise produced by it.

[furrysparkle]

Lovely info!

[bobsakamoto]

holy crap that was USEFUL, @DW2...totally gone upsize my out-ducts when i get around to it. Thanks!!

[Monkey Allen]

Thank you so much!

[DW2]

Here is a photo of my noise damper for my 8" oscillating fan. Try not to laugh too hard! with out it the wall that the shelf is mounted to became an amplifier!

[Monkey Allen]

Thanks again!

[Beach_Town_Brit]

You could build a sound dampening box around the fan unit, and then as DW2 says do everything you can to isolate the box's mountings. (I use bungee cords as DW2 suggests.) The goal would be to make the sound deadening box as airtight as possible. This could include rubber gaskets to attach your conduit, special sound deadening silicone seal to seal the boxes cable inputs etc. etc. If you google around you'll find some plans.

You can get sound deadening conduit too but it's pricey.

If you wanna go hog wild you could build a "dead vent" as described here:

https://www.gearslutz.com/board/studio-building-acoustics/650446-hvac-baffle-box-silencer.html

Do you have many bends in the path of your exhaust conduit? The straighter the conduit path the less noise it will transmit through the conduit. .

[bobsakamoto]

thank you kind sir!

[Monkey Allen]

All of you guys are helping me out tremendously. Thank you!