What type of material should be used to sound proof a grow room? +rep for help

Hey everyone, thanks for looking/helping. Much appreciated!


Here is the deal:

I've got a 10x10x8 room that runs a little loud into the hallway. I've got 1 main 700 cfm 8 inch max fan mounted to the wall (with shitty rubber under). It runs intake from the attic, and then exhausts onto the other side of the attic. I've turned it on a couple times and it makes a good amount of noise. Also I have two 300cfm 6" fans running exhaust in two tents, I can turn them to 1 power, but they still add to overall noise.



So I know I'm going to have to sound proof, but I have no idea what to buy to use for my soundproofing.

I've googled a bit, and read some conflicting opinions, yet I found almost nothing that helps me for a grow room.



I found these two products, upon searching sound proofing on google:

Mutli-Layer material, apparently used in home theatres and inside cars to dampen vibrations?
http://www.soundprooffoam.com/ultra-barrier-plus.html

Normal egg crate foam, in two thicknesses.
http://www.thefoamfactory.com/acousticfoam/eggcratefoam.html





tl;dr : What type of sound proofing should I use in a grow room running 3 fans totaling 1000cfm? so that the sound doesn't leak into the hallway?


+rep for help! much love everyone!

The biggest amount of noise is coming from your 8" fan and its mounting position.

You can build a wooden box around it and fill it inside with expanding builders foam. (Crazy foam I think USA calls it) then you can bungee cord the entire box from hooks mounted in the ceilings. This alone will help reduce noise levels. So to will insulated ducting.

J

I agree. First of all, consider drywall instead of that expensive MLV you linked. Second, suspend the fan from your wall / ceiling framing.

And forget eggshell foam for damned sure! It's ineffective and today's egg crate foams disintegrate quickly when exposed to even indoor environments.

Also every motor or engine has 2 RPM ranges where that machine is running happiest and with the least vibration. Usually a low RPM and a high one. Use a dimmer switch to SLOWLY lower the RPM to a point that most of the vibration disappears. Two vibes - one mechanical (the actual fan shaking) and one harmonic (the pulsating of air in waves instead of flowing in a steadier stream). Try to find the happy balance for your fan. With it isolated as described by the poster above.

i emptied my old can 66 filter, stuffed the ''egg crate'' foam in two layers where the carbon was, cut a 6 inch hole in bottom of filter. works great as a muffler...

Foams, regardless of the shape, will only stop low-volume noise, and only higher frequency noise. So anything loud will not see much benefit from foam, and and any low bass won't be affected at all by the foam, since the foam is very low mass. Foam and similar materials are used to reduce echo in a room but are not used for soundproofing.

Rrog said:

Foams, regardless of the shape, will only stop low-volume noise, and only higher frequency noise. So anything loud will not see much benefit from foam, and and any low bass won't be affected at all by the foam, since the foam is very low mass. Foam and similar materials are used to reduce echo in a room but are not used for soundproofing.

Click to expand...

you are referring to the acoustic foam pads specifically, yes? I bet that builder's spray foam insulation in a box does wonders... just want to make sure you meant the pads...

The insulating foam you're talking about is polyiso. Rigid and conducts vibrations. Not what we want.

Rrog said:

The insulating foam you're talking about is polyiso. Rigid and conducts vibrations. Not what we want.

Click to expand...

I guess that makes sense. Sure would be easy to work with without making the box gigantic, that's why I was considering it. I don't want to have to put a ton of negative space in the box as the space for my exhaust fan is sorta narrow.

What's the best thing to use to insulate the inside of a isolation box for a fan? Straight oldschool fiberglass insulation? Because I will avoid that stuff like the plague, it's so god damn unpleasant to work with. Anything but fiberglass.

I'm imagining a whole crapload of rubber stuffer into the negative space or something.

What is the "negative space" you're mentioning? The hollow area between the fan housing and the box around it?

Right.......pretty much the dead space between two barriers that negates the transfer of sound, vibration &/or temperature, sometimes filled with materials that also help prevent transfer.

Well you have two separate structures. The inner fan housing and the outer plywood. They are separated now, but foam would couple them. Lightly compressed fiberglass would be good. If you applied two thinner ply layers rather than one thick layer, and used Green Glue between the two, you'd be accomplishing a lot more.

good info here !
I will look to provide my grow box with some type of fan box.

What about the walls for a grow box? Is drywall better than plywood?

You want heavy, and you want cheap. Look at OSB for durability

Your venting into your loft ?

Have you got good airflow in your loft ? I`ve seen people vent into their loft without enough airflow up there and their loft has got all kinds of rot from it.

They sell silencers and box`s for fans or you can make them, tbh a well made fan with good bearings run at the correct speed should not make much noise if it`s mounted right like others have suggested.

Mylar and sound proof mylar all the way egg shell is junk..........

There is no soundproof mylar. Mylar has no mass so no stopping a sound wave.

OSB would be better as far as convenience in mounting equipment wherever you want. With DW, you would still need a more solid backing ,such as OSB, behind anything you want to mount that has any kind of weight to to it. DW is basically chalk(gypsym) wrapped in paper & crumbles easily.

Yes. And you want the weight / mass. Drywall is heaviest per inch, followed by OSB, then plywood. MDF is heavier (denser, really) than all of these but it's harder to work with

Sound shield "dry wall" or plaster board as its called in the uk + Mylar done