Exterior wall concept

UPDATED TO FORUM SPECS Hi all. I am in The Yukon Northern Canada. Temps range from -40 to +30 celcius. I have run a studio here for about 8 years now and have a pretty good grip on business frequency and styles of music/volumes etc. I track full bands maybe once or twice a month max, loud bands 2-4 times a year. The range though is from metal to folk(all acoustic) The property i am building this new studio on is 7 acres with 7 acre neighboring lots on 2 sides and green belt on the others(not to change) The land is populated by dense (mostly) pine trees, some spruce. Pretty rural I have decided to go with a standard 40x60 stick frame shop type building to be the basic shell of my new studio. It will have 14' high walls with scissor trusses on top @ 5-12 outer 4-12 inner. The walls will be 2x6 24" o.c. with 2x3 horizontal strapping 16" o.c., so R28, R40 in the ceiling. The floor will be a 4" cement slab poured separate from the footings with infloor heating fired by oil and wood boilers. Roofing will be asphalt shingles. Pics posted so far in thread... Main Trusses download/file.php?id=36559&mode=view Basic interior design download/file.php?id=36546&mode=view Thanks in advance for any input.

The builders have suggested i look into cutting strips of donna conna to put between the outer 2x6 wall and the 2x3 wall to stop transmission of sound to some degree.

Pardon my ignorance, but what is "donna conna"? In any event, regardless of what "donna conna" is, it wont help to "stop transmission of sound" unless the entire wall is designed correctly. I don't understand what you mean by "The standard walls are going to be 2x6 24" o.c. with 2x3 strapping 16" o.c.,". To me, that sounds like you are going to attach the 2x3 to the surface of the drywall on the 2x6? Or to the studs? What is the purpose of that? As always, a diagram or SkethUp model of what you are planning would help to determine if it will work or not. - Stuart -

Thanks for the comments Stuart. Donna conna is a medium density fiber board. The walls are designed as basic 2x6 but after they are insulated , 2x3 is strapped horizontally(or 90degrees to) across them on 16" centers and then insulated with extra R8 pink fiberglass. There is no board of any sort between the 2x3's and 2x6's they go right on the 2x6. Unless we put donna conna strips on the backs of the 2x3's where they attach to the 2x6. Does that make sense? Then usually drywall attaches to the out side of the 2x3. The reason for it all is added R value. In the north here it gets cold. The builder mentioned the idea of the donna conna and it seems sort of in the cracks of the whole single leaf thing. It's still attached but less rigidly. Better or worse? The drywall attached to the 2x3 will be 5/8ths and that will be the basic outer shell of the building. What will be exposed to that outer shell(internally) will only be the main large recording room sides And the outer walls of small Live room which will live in a corner. I will post a SU design soon, I'm slow with that thing.

seaweed, How much isolation do you need? This is the first question you should answer when trying to figure what type of isolating wall system you should build. I recommend that you do some noise testing in the neighborhood and determine how much STL (sound transmission loss) the walls must provide. That's for outside noise coming in. Don't forget there are thunderstorms and aircraft to deal with too. Now on to the noise that the studio will create; How loud will you be? What are the acceptable noise levels at the property line? Answers to these questions can help us guide you to the best isolation procedure. Good luck! Cheers, John

Hi John. The property is out of town. Its 7.5 acres with neighboring lots as big or more. Mostly pine trees and spruce, the odd deciduous. It's very quiet out here most of the time. The airport is a long distance away, the odd plane now and again but rare., it's out of line with the air strip. Road noise is very distant if at all. Thunder storms are very rare here. Wind is the most common issue as we are perched up a bit but still amongst lots of trees. The sound travels quite well around here though so i do want to be considerate to the folks around as like i mentioned, it is a quiet area. For example on the quietest days and nights you can hear folks 3 lots away talking loudly. What are your thoughts given that info?

How much noise do you plan to make (max)? Sound travels pretty well in the open country. -- And since the ambient noise will be rather low, the STL of the building must be proportionally increased. - John

given John's questions - maybe you should consider some measurements - set up some good size speakers which can pump 100-110db and doing a sine sweep, do some measurements around the edges of your property to see what sound is leaving your property. even though sound traverses easily, from a neighbors lot to yours, it doesn't always hold true vice versa depending on the topology of the land.

gullfo wrote:

given John's questions - maybe you should consider some measurements - set up some good size speakers which can pump 100-110db and doing a sine sweep, do some measurements around the edges of your property to see what sound is leaving your property. even though sound traverses easily, from a neighbors lot to yours, it doesn't always hold true vice versa depending on the topology of the land.

Do you mean within the building? if so...the building isn't up yet. We just poured the footings. As for how much noise i will be making, i record everything from metal to folk. So yeah, metal bands, that is how loud i will be and at night too. As i understand it, STL in my situation should be focused on mids and highs. As at night for example, if the lows leak out, the neighbors are inside their houses and it isn't an issue. In the day if lows leak out the general daytime curfuffel would mask them. So that leaves me with stopping detail of guitars etc from escaping. I have the luxury of trying one layer of 5/8s drywall, then if it doesn't cut it, 2 layers. Does that approach sound reasonable?

measure the area. you said you can hear people talking loudly. it might be useful to know how much of the 120db from your building location actually makes it to the edge of your property so you have some idea about how much isolation you need to build. you might be building yourself a concrete bunker in order to meet your isolation requirements as stated...

So yeah, metal bands, that is how loud i will be and at night too.

So count on 115 dB, minimum, perhaps pushing 120. That is LOUD.

As i understand it, STL in my situation should be focused on mids and highs.

No, it should be focused on lows. If you take care or low frequency isolation, the mids and highs will be taken care of automatically. Lows are the most difficult to isolate, since they carry the most energy, and are the longest wavelengths.

As at night for example, if the lows leak out, the neighbors are inside their houses and it isn't an issue.

I beg to differ! Normal house construction does little to stop lows, and under the right conditions could even end up amplifying the lows! I can promise you that, from first had experience: I live a couple of blocks away from what was a construction site about two years ago (the building is now finished, thank God). But back then, there were some rooms in our house which were absolutely unusable at some points during the construction. They were using some kind of machinery that put out lots of low frequency energy, which set up severely annoying resonance in a couple of rooms. Stand outside, and you couldn't hear a thing, but go inside, into one of these rooms, and it was LOUD. Low frequencies are unpredictable.

In the day if lows leak out the general daytime curfuffel would mask them.

The construction site didn't make any difference to us: day or night, it was the same. Until we got the municipality to shut them down at night, for disturbing the peace. :)

So that leaves me with stopping detail of guitars etc from escaping.

Guitars are easy. Drums and bass are not.

I have the luxury of trying one layer of 5/8s drywall, then if it doesn't cut it, 2 layers. Does that approach sound reasonable?

To be brutally honest, no it doesn't! Are you REALLY prepared to rip out all your treatment and gear after the room is already finished but doesn't work, just to add a second (or third) layer, and then put it all back again, only to find that the changes to the room dimensions screwed up your modal spread, and you now have additional problems with your room? That's your call, of course, but I certainly wouldn't take the risk, if that were my build. Like Glenn said: do the measurements, then decide how much isolation you need, then design the structure to achieve that. - Stuart -

Sea, You're guessing at what will work... - You will need at least STC65 & that doesn't cover the low frequencies which will be a problem. That is the problem with music isolation - low frequencies. And it is hard to block LF. For gypsum board walls this document lists different tested assemblies and shows the construction details of each. http://www.nrc-cnrc.gc.ca/obj/irc/doc/pubs/ir/ir761/ir761.pdf Good luck! Cheers, John

Soundman2020 wrote:

To be brutally honest, no it doesn't! Are you REALLY prepared to rip out all your treatment and gear after the room is already finished but doesn't work, just to add a second (or third) layer, and then put it all back again, only to find that the changes to the room dimensions screwed up your modal spread, and you now have additional problems with your room? What i meant was that the shell will go up and i can board it and do some tests pre the actual finishing of the interior. Put one layer on. Make some noise , do some tests, add another. But i am seeing now that the outer wall design might need to be re-thought from the start to save $ so................ Like Glenn said: do the measurements, then decide how much isolation you need, then design the structure to achieve that. I will do the sound test this week and let you know the results. Thanks everyone for the good advice

just a "measure twice, cut once" mentality i have...

Interesting, we just got 2 inches of snow. How do you think that will affect the lows travel for my test? pics of site for some reference........ http://www.seaweedmusic.com/pics/new%20 ... %20dry.jpg http://www.seaweedmusic.com/pics/new%20 ... b-snow.jpg http://www.seaweedmusic.com/pics/new%20 ... /south.jpg http://www.seaweedmusic.com/pics/new%20 ... d/west.jpg

snow. it's one of the reasons no one can hear Santa. :wink:

seaweed wrote:

Interesting, we just got 2 inches of snow. How do you think that will affect the lows travel for my test?

Yes, but not as much as the highs. IBP Report 486, Sound Absorption of Snow Andre

gullfo wrote:

snow. it's one of the reasons no one can hear Santa. :wink:

Obviously. But what i am getting at is isn't there some sort of brainiac equation where you multiply the number of trees by their average height then multiply by the number of inches of snow, divided by the Elevation above sea level(2450ft here) X the density of frozen H20 X Pi squared and trigometry that MahFucka to the length of the sound wave or some shit?

AVare wrote:

seaweed wrote:

Interesting, we just got 2 inches of snow. How do you think that will affect the lows travel for my test?

Yes, but not as much as the highs. IBP Report 486, Sound Absorption of Snow Andre

AhhHa! Thanks

seaweed wrote:

But what i am getting at is isn't there some sort of brainiac equation where you multiply the number of trees by their average height then multiply by the number of inches of snow, divided by the Elevation above sea level(2450ft here) X the density of frozen H20 X Pi squared...?

Aah, you were asking just about snow. Tree height affects the frequencay range absorbed. More significantly the foliage has the greatest impact, at higher frequencies. Mother nature is kind to acousticians, for a change here. As foliage decreases, snow increases. Both absorb highs so they sort of balance each other. Like black flies and polar bears. Elevation in and of itself has no effect. Temperature gradients have a huge effect. Frozen H2O is snow. :P Andre Edit: corrected HTML errors and non-english spelling.

Hey Guys, no update on the sound transmission yet, got too cold, too snowy etc but i will have some results soon. A quick inquiry though. We are looking at the trusses and i of course am pushing for more cubic feet inside. The outer slope of the scissor truss will be 5-12 and the inner could be 4 or 5-12. But i wondered if i might be better off with more airspace in the insides of the trusses (4-12 pitch inside), sound transmission wise. Could that space inside the trusses be treated with hangers etc and be a helpful absorber like in the ceiling of a control room? I do want to put Fir or pine t&g 1x6 on the inside ceiling of the main rec room, so it will be a hard surface, probably with drywall under it. Thoughts? Thanks.

the space in the peak of the truss area could be used for bass trapping. you could line the inside of the inner trusses with drywall to create the isolation and use the peak for bass trapping covered with cloth and some widely spaced slats and then add the pine t&g on the exposed ceiling spaces for a nice wood finish.

I'm having trouble picturing that, and i know you are a wiz with the graphics, could you....

check the Ellamy build where there is trapping added to the peak in the ceiling http://web.me.com/ellamystudios/Ellamy_ ... Build.html

I get it now, i was stuck on using the inside of the trusses for the absorption space.

even with the inside of the trusses being used for absorption, the peak will still be useful for bass trapping.