Building acoustic treatment on a budget

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john12ax7 said:
If you spend a lot of time in the room , especially if it's a bedroom, then you should also look into the health aspects and irritation of the various materials. It affects different people in different ways.

I treated my room with recycled cotton.
and flammability for fire safety.

JR
 
for an iso room that has a chance of being knocked down and relocated;
if you can find something like this
https://www.amazon.com/Double-Angle-Edge-Material-Length/dp/B0711ST6S8/ref=pd_sbs_60_6/140-2490351-2122831?_encoding=UTF8&pd_rd_i=B0711ST6S8&pd_rd_r=7a057439-6dfa-11e9-8500-7b430b359b4b&pd_rd_w=PqSH6&pd_rd_wg=CvsrL&pf_rd_p=588939de-d3f8-42f1-a3d8-d556eae5797d&pf_rd_r=ZM6VHVGD22BGRNH1SPXK&psc=1&refRID=ZM6VHVGD22BGRNH1SPXK

but able to accomadate 3/4" plywood a room within a room could be fashioned with padding in between and rubber pucks to decouple floor.

an effective door and ventilation are always a challenge
 
So I'm planning on building a booth shortly. I have my materials planned out, I'm gonna be using a bunch of 4x8 OSB boards (because I'd like to take this with me when I move) that are 7/16" thick. I'm planning to double up on them to get almost 1 inch thick walls (unless that's overkill). Planned size is 4'x6'x7'.

For ventilation will I need two fans, one to bring in air, and one to pull out the old air, or is just one fan pulling new air in okay?

So far the materials are gonna be about $500 CAD. Which doesn't seem too bad considering a premade booth costs like $4000.

Materials so far are:
-22x 4'x8' OSB boards (7/16" thick)
-2x 4 inch wide 10 ft long flexible duct
-1x Rockwool Safe n' Sound

I haven't decided on the fans yet or LED lights.

I'd like to make it easy to tear down and set up too, but I'll take just stable enough I can take it apart and move it.
 
Bumping to ask a question, is about .5" thick enough to reduce a lot of sound from coming into and leaving the booth? Or should I go with my plan to make it about an inch thick on every side?
 
Icantthinkofaname said:
Bumping to ask a question, is about .5" thick enough to reduce a lot of sound from coming into and leaving the booth? Or should I go with my plan to make it about an inch thick on every side?
There are many unknowns in your question, starting with how much is enough.
A .5" plank weighs about 6kg/m²; according to the experimental law of mass, that would result in less than 20dB wide-band attenuation. That would probably be somewhat higher at mid-high frequencies and significantly lower at low frequencies. There would be a point were the resonance of the panels may result in increased attenuation, but it's hard to control. Doubling the thickness would not result in much greater attenuation (6dB in the better case), but making a sandwich with a layer of soft material would be beneficial.
OTOH, there are many losses due to the door and aeration ducts that would actually be the limiting factor.
 
abbey road d enfer said:
There are many unknowns in your question, starting with how much is enough.
A .5" plank weighs about 6kg/m²; according to the experimental law of mass, that would result in less than 20dB wide-band attenuation. That would probably be somewhat higher at mid-high frequencies and significantly lower at low frequencies. There would be a point were the resonance of the panels may result in increased attenuation, but it's hard to control. Doubling the thickness would not result in much greater attenuation (6dB in the better case), but making a sandwich with a layer of soft material would be beneficial.
OTOH, there are many losses due to the door and aeration ducts that would actually be the limiting factor.
If doubling up won't do much extra, I might as well spend the extra money on some extra insulation for treatment. The boards are super cheap at $10 each which is why I was planning on using so many, and I'll only be saving $100 if I don't double up (but it'll be a much easier and much more "portable" project) I was planning to fill the inside with moving blankets and then additional treatment.

Out of curiosity, how much is 6 dB actually when we're talking about attenuation of external noise?
EDIT: Looks like 10 dB is how much louder a sound has to be to appear twice as loud (and 6 dB is double the sound pressure, correct me if I'm wrong, I found this via Google), so if I could achieve 20 dB of attenuation, does that mean that I should be about to cut down on most outside noise (neighbours, cars, etc.) to a reasonable level?

I decided to use OSB because it's cheap and I'll be able to unscrew the booth when I move and reassemble it. I know it not being actually air tight (not sealing gaps between the wood, or does that "soundproofing tape" actually work for that?) will cut down on the effectiveness (unless there's an easily removable method of doing it, I'm not planning to move for another year or two until I have the money I want saved up)

I'd really just like to cut down on noises from outside (and noises from neighbours, so not being able to hear kids outside, neighbours' music, cars, lawn mowers, etc) enough that I can use a noise gate and still have a really clean enough recording.
 
quality 3/4” plywood is a better material from a dimensional stability, durability and fastener holding perspective. Osb is kinda gross.

Airtight is Important  for isolation but contrary to ventilation.  A damped labyrinth is required and a pressure differential for air to exchange.
number of blowers will need to be derermined empirically— its ohms law like
Higher resistance narrower passage will require more pressure to turn over an equivalent air volume,  and will likely be more of a noise source than lower pressure.

Attenuation is usually not flat, lower frequencies are harder to isolate away. Hi pass filter will be cheapest and easiest move toward that goal.
 
shabtek said:
quality 3/4” plywood is a better material from a dimensional stability, durability and fastener holding perspective. Osb is kinda gross.

Airtight is Important  for isolation but contrary to ventilation.  A damped labyrinth is required and a pressure differential for air to exchange.
number of blowers will need to be derermined empirically— its ohms law like
Higher resistance narrower passage will require more pressure to turn over an equivalent air volume,  and will likely be more of a noise source than lower pressure.

Attenuation is usually not flat, lower frequencies are harder to isolate away. Hi pass filter will be cheapest and easiest move toward that goal.
The reason I wanted to use OSB is just because it's really cheap, so I can double or triple up on the amount for what plywood would cost since a 4x8 (7/16" thick) is about $10 and similar plywood is $50 here.
 
I ended up just buying the 4x6x7 plans from DAW Box. I'll just source the interior treatment myself. Probably not gonna order anything until I actually get the book and DVD from DAW box. It seems like the really expensive part is when you use that expensive acoustic foam to treat the inside ($700 USD for their 4x6x7 foam kit).
 
So in order to treat the inside of said booth, I would need 144 squares of 2" thick 12"x12" foam. That'll cost me about $300 USD without including corner bass traps. Would fiberglass be cheaper and more effective than the foam?
 
Do you want to sit in a closet full of fiberglass?

https://www.google.com/search?q=fiberglass+itch
https://www.reference.com/health/remedy-fiberglass-rash-736f0a4434eb0e8c
https://healthfully.com/treat-fiberglass-irritated-skin-7284890.html
 
Icantthinkofaname said:
So in order to treat the inside of said booth, I would need 144 squares of 2" thick 12"x12" foam. That'll cost me about $300 USD without including corner bass traps. Would fiberglass be cheaper and more effective than the foam?
In my expereinec the "foam" products degrade quite fast.
The non-degrading melamine foams like Basotect are very easy to damage. The bandwidth on all is not wide.

Totally avoid Fiberglass based insulation. The irritation on the skin and lungs is a serious issue.

Look for Mineral Wool insulation. One brand is Rockwool. The modern mineral fibers are shorter and supposedly safer. I am in construction and notice a huge difference between brands. The other guys on site confirm this too. So far Rockwool has the least irritation fo me when working with it.
You must still cover with a breathable fabric. A medium weight fire-resistant Molto fabric as used in theaters and stages works well.  Keep the workspace clean and wear a mask. Dispose of the clothes and scrub-shower long afterwards.
 
tony hunt said:
In my expereinec the "foam" products degrade quite fast.
The non-degrading melamine foams like Basotect are very easy to damage. The bandwidth on all is not wide.

Totally avoid Fiberglass based insulation. The irritation on the skin and lungs is a serious issue.

Look for Mineral Wool insulation. One brand is Rockwool. The modern mineral fibers are shorter and supposedly safer. I am in construction and notice a huge difference between brands. The other guys on site confirm this too. So far Rockwool has the least irritation fo me when working with it.
You must still cover with a breathable fabric. A medium weight fire-resistant Molto fabric as used in theaters and stages works well.  Keep the workspace clean and wear a mask. Dispose of the clothes and scrub-shower long afterwards.
Any specific type of rockwool I should look for? Is the Safe N Sound labeled stuff good? This is the one I'm looking at:
rw-na_safensound_w16.jpg


If it's not good what Rockwool stuff is closest in performance to Owen's Corning 703 if you know?
 
Hey there,

so i just saw this thread and I think I can chime in here, since I was also on the hunt for diy acoustic treatment on the rather cheap.
Basotect, Rockwool and whatever else are all called "porous absorbers", since they all work by slowing down the air by friction. Now they are most effective, when the velocity of the sound wave is high. Since the velocity of a wave bouncing of the wall is the 0 right at the wall, they are more effective, when you leave an air gap between the wall and the absorber.

The capability to absorb sound waves is determined by the thickness of the absorber, the "flow resistivity" and the air gap. Absorbers with a high flow resistivity, i.e. Basotect, are pretty effective up until around 200mm thickness and having them thicker doesn't really make them more effective in absorbing low frequencies, hence they are often used as broadband absorbers but make pretty bad thick corner bass-traps. Now  i.e. Rockwool offers different materials with different flow resistivities, which you can see in the "spec sheets" they publish.

You can use this calculator ( http://www.acousticmodelling.com/porous.php ) to determine the absorption coefficient of any given porous absorber with any given air-gap. Just look up the flow resistivity at the Rockwool website, type in the maximum thickness the panels can have and compare different materials or types of Rockwool side by side.

Now I didn't go the Rockwool route out of health concerns and opted for a natural absorber. There are a few different ones available here in Germany but the main types are: hemp, jute (made out of jute sacks that were used to ship coffee with) and wood fiber. I opted for wood fiber since it was the cheapest and very effective, as long as you make the absorbers kind of thick - at least 150mm. If you want to build huge corner bass traps, the hemp absorbers are usually even more effective. All of the materials are fire rated and really nice. They are good to work with, since you don't need any protection or gloves, but they might smell a bit for the first couple of weeks. But I mean, the smell of cut would is pretty nice, so thats not really a con.

Best
Jannis
 
So would single layer construction with Rockwool walls (which would then be covered with fabric) help with attenuation? Or does insulation like that actually not help with sound transfer and just kills the echo?
 
Icantthinkofaname said:
Any specific type of rockwool I should look for? Is the Safe N Sound labeled stuff good? This is the one I'm looking at:
rw-na_safensound_w16.jpg


If it's not good what Rockwool stuff is closest in performance to Owen's Corning 703 if you know?

https://www.youtube.com/watch?v=ANEwt4WtBAQ
 
> So would single layer construction with Rockwool walls (which would then be covered with fabric) help with attenuation?

Hardly at all.

> Or does insulation like that actually not help with sound transfer and just kills the echo?

This.
 
I once, when living situation necessitated, built a freestanding booth out of chip board completely lined with Auralex Sheetblok inside, 2’ x 4’ x 7’

It worked amazingly well for isolation from outside noise but had no ventilation and poor acoustics inside. It might have been well suited to voice over, but it was poor for sung and screamed vocals. The old tent of moving blankets always yielded better results.
 

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