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PostPosted: Tue Aug 23, 2011 11:20 am 
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First, please check the rules for the forum: There is something missing... :)

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After doing some more reading on other sites, the best advice I could find is to just add a second layer of sheetrock to the existing wall with a coating of silicone caulking.. is it true that this is the best way?
It may or may not be the solution you are looking for, but most likely not. It all depends on the way the wall is built already.

In the science of acoustics, there is something called "mass law", which defines how much extra isolation you can get by doing things like that (adding an extra layer of drywall). Mass law says that each time you double the total mass of the wall, you get an increase of 6 dB in isolation. so for example, if the existing wall has one layer of 5/8" drywall on each side, and you add another two layers to your side, then you have doubled the mass, and the wall will now isolate 6 dB better than it did before.

The problem, of course, is that 6 dB isn't very much. A change of 3 dB is about the smallest change that most people can hear: any less than that and most people would say that it didn't change at all. A change of 10 dB is the point where most people say that the level went down by 50%. So a change of 6 dB is way less than half. Noticeable, but only just, and certainly not what you need if you hope to keep the neighbors from calling the cops on you!

OK, so you think "I'll just add more mass". OK. So to get another 6 dB of isolation, you need to double the mass again. You already have four layers of drywall (the original 2 plus the 2 you added). So to double the mass now you need to add another FOUR layers (for a total of eight), and all you have achieved is reducing the level by around 12 dB, or roughly half. And that is in theory: in practice you most likely wont even get that much, for other reasons.

So clearly, this thing of "adding another layer" is not going to work. That's why studios are not built like that! Because it doesn't work, unless you are prepared to put ridiculous amounts of mass into your wall. It's a huge amount of expense for very little return, and is not the way to do it.

The "extra layer of drywall" might help if you have a problem where you can hear your neighbor talking on the other side of the wall, or hear the TV, but it is useless when you are playing the drums, for several reasons. Among those reasons: Your drums are about ten thousand times as loud as your voice! No, I'm not kidding. That really is the number. Your talking voice is around 70 dB, your drums are around 110 dB. That's a difference of 40 dB (give or take a few). The decibel scale is logarithmic, so small numbers mean small changes, and big numbers mean huge changes. An increase of 10 dB is ten times the power. An increase of 20 dB is 100 times the power. An increase of 30 dB is 1000 times the power. And an increase of 40 dB is ten thousand times the power. So your drums are putting out roughly ten thousand times the power of your talking voice. Surprising but true. Stopping that amount of noise is not easy to do, and a single sheet of drywall is useless for that.

The next problem is frequency: the energy in your talking voice is mostly within the 500 Hz. to 4 kHz. area. It turns out that those frequencies are easy to block. A sheet of drywall will help a lot there. But with drums, most of the energy is in the low end of the spectrum, and it turns out that that part is really hard to block. Ever walked past a disco or night club at a distance? What do you hear: Only the "boom.... boom... boom..." of the drums and bass. You don't hear the cymbals, guitars or voices, because those are easy to isolate, while drums are not.

So those are the issues facing you: the levels are extremely powerful, and most of the energy is in the area of the sound spectrum that is the hardest to block.

In other words, a single sheet of drywall is going to do nothing noticeable.

Then, you have the issue of "flanking". That's an acoustic term that basically means sound is getting around your wall, not going through it. With that problem, it doesn't matter how good the wall is, because the sound is just ignoring the wall and taking a different route to get to your neighbor. Maybe it is going through the ceiling, or the other walls, or out through the window, or a door, or even through the floor. There are many ways that sound can bypass a simple wall.

Finally, there is the "aquarium" issue. By that, I mean that your room is like an aquarium, and sound is like water. In order to keep the water inside the aquarium, you have to put glass on all six sides: left, right, front, back, top, bottom. If you take the glass out of any side, the water gushes out. You have to have all six sides in place to keep the water in. Same with your drum room: you have to have all six sides in place to keep the sound in.

You might be thinking "But the problem neighbor is only on ONE side of me! I just need to block sound going THAT way". Back to the aquarium: Can you take the glass out of only the left wall, and still keep your feet dry? Nope! :( "But my feet are underneath! So surely the glass in the bottom is all I need!". See the problem? It doesn't matter WHICH side you take out from the aquarium, the water still gushed out all over. Same with sound. It doesn't matter which wall you leave out of your room, the sound will still "gush out all over" if they aren't all there. And once it is out, then it expands from that point in a sphere, in all directions, so your problem neighbor is going to hear you no matter how good your single wall is. Or two walls. Or three. Or four.... You have to do all six. There is no way around it. The laws of physics dictate the you cannot do what you want unless you treat all six walls. There are no magical materials that you can put on that wall. You could replace that wall with a six-foot thick lead block, and your neighbor would still hear you clearly.

So what IS the solution then? I've told you all about what WONT work, so how about what WILL work? How about telling you the way studios ARE built, instead of the way they are NOT built?

Quote:
Also, if I'm doing this in my garage and don't want to have to do this to the entire garage, is there a reasonably simple way to section off the corner that my drum set is in that provides noise reduction?
Yup! You are in the right place for that, for sure! That's what this forum is alllll about! :)


OK, it turns out that the solution is not that complicated: you just build another room inside your garage. That way, instead of having just one layer of mass between you and the outside world, you have two layers, and that changes everything. Different ball park! different game!

It turns out that you can get very high levels of isolation by separating your mass into two layers, or two "leaves" with an air gap between them. It changes the rules entirely, because now you are dealing with a tuned system, which is a very different thing from simple mass. Say good bye to "mass law", and throw it out the window! Say hello to MSM law. MSM law is your friend if you want lots of isolation at at reasonable cost. In fact it is your ONLY option if you want lots of isolation at a reasonable cost! Remember with mass law you could get an increase of maybe 12 dB with eight layers of drywall? Well, with MSM law you can get around 50 dB of isolation, and with only four layers of drywall! Sounds a bit better, doesn't it? :)

It works like this: you need two "leaves" of mass, separated by an air gap. Two sheets of drywall separated by air. That's the entire secret! This is called "MSM", for Mass-Spring-Mass. The two sheets of drywall are the two "masses", and the air in between is the spring. It is that simple. Two leaves of mass, with air in between.

And you already have half of the solution.

What this means in practice is that the existing shell of your garage is the outer leaf, and it is already there. You only need to build the inner leaf. Just put up a 2x4 stud frame around the area where you want your drums (four walls and ceiling), and put 5/8" drywall on only ONE side of those studs, NOT on both sides. If you do both sides, that would make a 3-leaf wall, which once again changes the rules, and makes the isolation really bad again. No 3-leaf. No 4-leaf. Only ever two leaf. There are different mathematical equations that govern each type of wall, and it turns out that 2-leaf is the only one that works when you need to isolate low frequencies.

So that is your solution, plain and simple: Build a simple stud frame, and put drywall on it.

There are a few other things you need to take into account, such as sealing the two leaves air-tight, and figuring how many layers of 5/8 drywall you need to put on your inner leaf (it will be more than one layer, for drums), and how big the air gap between the two leaves has to be, but this is the basic concept. (You also need to consider doors, windows, HVAC and electrical, but we'll get to those later).

That is how studios are built, and that is your only option if you want good isolation on a tight budget.

If you look around the internet, you often find places that tell you all about their incredible "soundproofing" products, that you only need to put a thin layer on your wall, and it will silence everything short of an atomic bomb! Don't fall for it! It is pure garbage. Marketing hype. Not true, and no basis in science. Sound is a physical phenomena, and the laws of physics govern how it works. You cannot wish away those laws, or hope that they won't apply to your garage: they do. So forget the marketing hype, and just do it the way normal studios are built: two leaves, MSM, sealed. Period. End of story.

If you want to know more about how to do this, the look around the forum: there are many threads by folks with exactly your problem, and you can see how they have built their rooms, and how successful they have been.

But please check the forum rules one more time, for that thing you are missing! :)

- Stuart -

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PostPosted: Tue Nov 22, 2011 5:20 pm 
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Hi to all of you! Well I have a few questions. Do the principle of setting up the panel away from the wall works also for acoustic foam? Have you an idea for hanging the panel off the wall? Also, i've heard that the particles of fiber glass or rockwool are bad for your health. Isn't burlap, th 8) 8) e fabric used for this design, a very porous material for stopping this particles from going into the air? Also, I'm on a 7,83ft x 9,46ft room, an I'm on a budget. Should I start treating mi front wall or should I start treating the corners of my room?

Well these are a lot of questions, thanks, besides, nice site and nice thread, already learned a lot. 8)


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PostPosted: Tue Nov 22, 2011 10:12 pm 
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Hi "hernangil". Please check the rules for posting on the forum. You are missing something.

Quote:
Do the principle of setting up the panel away from the wall works also for acoustic foam?
Yes. It's exactly the same. By placing the foam away from the wall, you are placing it at a location where it can treat lower frequencies, since it is in the peak velocity zone for longer wavelengths.

Quote:
Also, i've heard that the particles of fiber glass or rockwool are bad for your health.
You heard wrong. Here is the truth:
viewtopic.php?f=2&t=1742&p=12705&hilit=fiber+health#p12705

Quote:
Isn't burlap, the fabric used for this design, a very porous material for stopping this particles from going into the air
Even though the fibers won't give you cancer, they can still cause damage to your equipment (for example if they get into the faders of your console, or build up on the fans or inside the cooling path of your equipment), and the dust they leave is just not pretty! So yes, you can use burlap or other types of cloth to reduce the amount of fibers floating around. You can also put plastic across the front of your bass traps, which is good acoustically as it reflects some of the highs back into the room.

Quote:
Also, I'm on a 7,83ft x 9,46ft room, an I'm on a budget. Should I start treating mi front wall or should I start treating the corners of my room?
Both! You need bass traps in the corners, and you also need to treat first reflections.


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PostPosted: Thu Mar 06, 2014 3:55 am 
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great post! I plan to build some of these!

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PostPosted: Tue Apr 14, 2015 3:19 am 
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where can i get Owens-Corning 703 for 17$ shipping included? everything i find online is 30$ or more


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PostPosted: Tue Apr 14, 2015 5:04 am 
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maxwellcrespo wrote:
where can i get Owens-Corning 703 for 17$ shipping included? everything i find online is 30$ or more


There is an announcement at the top of the forum about what to do to assure getting as many responses as possible.
The announcement leads to this post (click here). Actually, several people, who are experts on this forum, will most likely not reply if you don't do what is written in that post. Many others who are very helpful, will most likely not reply out of respect for the moderators' wishes.

- Stuart

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PostPosted: Tue Apr 14, 2015 6:13 am 
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Soundman2020 wrote:
maxwellcrespo wrote:
where can i get Owens-Corning 703 for 17$ shipping included? everything i find online is 30$ or more


There is an announcement at the top of the forum about what to do to assure getting as many responses as possible.
The announcement leads to this post (click here). Actually, several people, who are experts on this forum, will most likely not reply if you don't do what is written in that post. Many others who are very helpful, will most likely not reply out of respect for the moderators' wishes.

- Stuart


Sorry Im just trying to figure out where/how to get insulation so i can start building my bass traps and panels. Im located in st. petersburg FL


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PostPosted: Tue Apr 14, 2015 6:46 am 
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Quote:
where can i get Owens-Corning 703 for 17$ shipping included?
The first post in this thread, where the price of US$ 17 is mentioned, is now a bit more than 7 years old. I doubt that you'll still be able to get 703 for that price today.

But even at US$ 30, it's still a good deal: Buying commercial treatment panels would be much more expensive than that, and 703 give excellent results, so it would still be worth your while.

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PostPosted: Mon May 25, 2015 7:49 am 
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Does anybody know where the PHOTOS for these $25/$42 panels are? I think they have been removed from the forum posts.


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PostPosted: Mon May 25, 2015 10:37 am 
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Quote:
Does anybody know where the PHOTOS for these $25/$42 panels are? I think they have been removed from the forum posts.
I'm seeing them just fine. They are still there.

In order to see photos on the forum, you have to be a member, and you have to be logged in.

Making those panels will probably cost a little more today: the thread is about seven years old, and prices have gone up since then. But it's still a very simple, inexpensive way of making very useful panels that perform well.

Please also read the forum rules for posting (click here). You seem to be missing something! :)

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PostPosted: Thu Jul 16, 2015 2:33 am 
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This is an excellent thread! Thank you, gentlemen, for helping us understand more about this mystic "dark art." :D


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PostPosted: Thu Jul 06, 2017 3:44 pm 
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[quote="studio_drums"]Materials needed:

- Owens-Corning 703 ($17/panel incl. shipping)
- 8' Furring Strips (1"x3") ($1.24 each)
- 'Heavy Duty' Stapler with 1/2" staples ($3-4 per box)
- Burlap Fabric 1 1/2 yards @ $2.09/yard ($3.00)
http://www.hancockfabrics.com/product--9186.shtml
- Spray Adhesive ($3-5 per can)
- Liquid Nails ($3.17 per tube)
- Hammer
- Power Saw

Cool design, but where are you finding 703's for $17/panel? I'm seeing prices from $33 per panel (in a pack of two) to $130/panel individually at Home Depot.

Care to link, mate?


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PostPosted: Thu Jul 06, 2017 3:49 pm 
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Cool design, but where are you finding 703's for $17/panel? I'm seeing prices from $33 per panel (in a pack of two) to $130/panel individually at Home Depot.
Well, considering that you are replying to a post that is over NINE YEARS OLD, I'd say that it's not surprising prices have changed just a little! :)

Also, please read the forum rules for posting (click here). You seem to be missing a couple of things! :)

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PostPosted: Thu Jul 06, 2017 11:49 pm 
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I just got 24 pieces from a drywall and insulation supplier for $250. That is a little over $10 a board.

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