Soundproofing query

[jinglesmountjoy]

Hi all...This would my first offical post.

I'm in the fortunate position of building my studio from the ground up but want to avoid soundproofing overkill. It'll be used for voice work so keeping sound out is my only concern (rather than keeping it in).

I live in a small town in the Niagara region of Ontario, Canada and the biggest noise concern would be the odd Harley/ATV driving by at an inopportune time.

I've attached a drawing of what I'll call, "plan A"...sorry, but the measurements in the drawing are metric.

The largest room is obviously the garage - 23'x20' & about 11' feet high and all walls finished with drywall.
The rectangular structure at top left is "the studio" - roughly 9'x14'
Within the studio...the control room (right) & isolated voice booth (left)

I had intended on using QuietRock 510 but after doing a search on this forum and reading through the threads that came up, I've decided against it. So this is what I'm thinking...

"The Studio" will be built using standard 2x4 wall construction with a layer of 5/8" followed by 1/2", both on the garage side only and insulation called "Roxul Safe 'N' Sound" between studs.

Inside, the control room will also have a layer of 5/8" and a layer of 1/2" but in the room housing the voice booth, I will simpy cover the insulated stud wall with fabric.

The voice booth will also be of standard 2x4 construction but the outside surface will have NO drywall followed by the same Roxul insulation between the studs and finally on the inner surface, the same 5/8" and 1/2" layers.

My thoughts on the ceilings are exactly the same construction with the ceiling over the control room having the double drywall treatment and over the voice booth having the insulation/cloth treatment.

The voice booth would also have it's own ceiling with double drywall on inside and of course...fabric on outer surface.

Obviously, without being here, it's hard to give your opinion but I'm looking to get everyone's thoughts. Do you think it's enough?
Appologies for the lengthy post.

 

[John Hile]

Hi,

I'm kind of new here myself, but I can get you in the right direction.

In addressing sound isolation to stop Harley Davidson sounds you have to address low end frequencies.

First of all if you have the opportunity, make a double stud or staggered stud wall framed @ 24" OC. These are both decoupled wall types and you get a great deal of low end performance from these assemblies.

If you are concerned with loosing too much space with either of those two wall assemblies, then perhaps thinking about using some Resilient Clips and Hat Channel to decouple. Again frame studs @ 24" OC.

If you don't want to do any decoupling (which I Highly recommend you do) then you would want to build out your framing @ 24" OC. This will allow for more flex in your panel which is good.

You will want to close all of your walls with the double DW. You mentioned that "...will simpy cover the insulated stud wall with fabric.". If you only do this all of your sound isolation will depend on the DW on the other side. That's not going to be enough mass to accomplish what you want to. To control interior room sound quality you will want to add some acoustic panels to reduce reflections.

Insulation's part of the sound isolation equation is to absorb mid-high end frequencies. I've seen test reports that indicate that within a wall, insulation is insulation, and what I recommend is to use regular inexpensive R-13 in the walls and R-19 in the ceiling.

The four basic elements of sound isolation are:
Mass (Double Drywall)
Absorption (Insulation)
Decoupling (Double Stud, Staggered Stud, or Clip/Hat Channel)
Damping (A visco-elastic damping compound)

I would recommend that you do your walls and ceiling the same. Like this:

On double stud or staggered stud walls:
Stud (Insulation in cavity) > 5/8" DW > Damping Compound > 5/8" DW

On Resilient Clip/Hat Channel Wall: (The DW gets attached to Hat Channel, not stud)
Stud (Insulation in cavity) > Clips on Stud > Hat Channel on Clip > 5/8" DW > Damping Compound > 5/8" DW

It is common to see that if not using a damping compound to use two different thicknesses of DW, but when using damping compounds (which takes the resonance out of the panel) Mass is better, so 2 layers of 5/8" is the ticket.

I see that my post got fairly long as well.

I hope it helps.

John

 

[Roguetitan]

another concern you should have is outside noises, barking dogs and car sub woofers turned up can really screw up a recording session

if I could afford a block structure with a flat concrete roof would be my preference

overkill is good if you can afford it

 

[jinglesmountjoy]

John, that's great detail for a newbie! You know your stuff.

The "fabric" method was due to something I had read about on several forums (I believe it was something like MASS-AIR-MASS) which said you should avoid having drywall on the surfaces that will face the air side of each wall and that the more space between those walls, the better.

It had something to do with the two hard surfaces actually acting against the isolation efforts by acting as a sort of an "echo or reverb zone" where the waves bounce back and forth in that cavity rather than being absorbed.

I don't know if that makes any sense at all, but it made sense the way it was posted wherever I read it. Sorry for being so vague

Regarding the wall construction, I had originally intended on going that route but began wondering if I was heading into overkill. I guess I'm just paranoid that I'm going to spend all this time and money only to have someone come over and tell me I went way too far and could have saved myself 35%, two days work and still had the same quality isolation.

 

[John Hile]

Thanks jinglesmountjoy. I'm only a newbie on this forum. It cracks me up. I kind of like it!

I think what you are referring to is what is referred to as a Triple Leaf Effect and that is not a good thing.

A Triple Leaf is usually constructed like this: Panel > Airspace > Panel > Airspace > Panel

With this assembly, sound within the two smaller airspaces will resonate all the drywall and will result in a poor performing wall. By simply taking the center panel out, Panel > Airspace > Airspace > Panel, the performance of the wall would increase.

Mass-Air-Mass systems are what all walls are. That's why the more Airspace you have, the better within the wall You also have to have mass, decoupling, and damping.

I believe that a worse situation would be to have someone come over and comment on the motorcycle that just went by. Soundproofing does not have to be expensive if done correctly, and since you are in the beginning phase of your build, you have the opportunity to get great results without a huge bill.

 

[jinglesmountjoy]

With this assembly, sound within the two smaller airspaces will resonate all the drywall and will result in a poor performing wall. By simply taking the center panel out, Panel > Airspace > Airspace > Panel, the performance of the wall would increase.

But by puting drywall on the inner walls that face the voice booth as well as on the outside wall of the voice booth, won't I be creating that "triple leaf effect" you referred to...Panel(garage side of studio wall)>Airspace(insulation)>Panel(inner side of studio wall that faces booth)>Airspace(area between the two walls)>Panel (outside surface of booth wall)>Airspace(insulation)>Panel(wall surface inside booth)? I would have thought to avoid the panels I have in bold

You also have to have mass, decoupling, and damping.

It seems as though I have the mass and the dampening I think I can take care of after the build...but what exactly does decoupling do...what is the science behind it? Sorry if that's a rather remedial question.

Oh yeah, I made I slight modification to the design. (attached)

 

[John Hile]

Your description got kind of confusing, but I looked at your attached pic. and it helped. I see that your booth is on the left and that you are planning to build a "room within a room" or double stud construction. So... Yes you would be creating a triple leaf if you keep those "inner wall" panels. Get rid of those and you will have a nice big air cavity that you can put insulation in.

John

 

[RICK FITZPATRICK]

A word to the wise. Anytime you partition off space, especially where any ELECTRICAL is concerned, the Building Inspection Dept wants to know about it. Especially where an EGRESS path involves access to a room THROUGH another room. I suggest you apply for a Building permit prior to construction. Insurance companys LOVE to void insurance policies should something happen regardless if its caused by something you installed WITHOUT a permit. Another thing. After viewing you pdf., something tells me this "booth" won't pass inspection, because of the sheer minimum depth of the room at 3.5 feet. I could be wrong, but HABITABLE space usually is defined by CODE with minimum dimensions. I'd check with your Building inspection Dept. on this. Not only that, but I would suggest using Resiliant Channel for this space instead of building a double wall setup. Looks like a LOT of work for a VERY SMALL room. Ever stood in a closet? By the time you put in enough absorption to make it work, you won't be able to turn around. Sometimes things on paper give NO scale to actual space.

 

[John Hile]

Rick makes an awesome point about getting permits and checking out the details that way. I would suggest looking into that as well.

I would recommend the use of Resilient Clips and Hat Channel for your decoupling as opposed to Resilient Channel. Resilient Channel is not nearly as dependable as it can be short circuited during installation very easily. This method, (as opposed to 'Room within a Room") as Rick mentioned, will save valuable space.

Here's a great article that will answer some questions regarding Clips & Hat Channel and Resilient Channel: http://www.soundproofingcompany.com...es/furring_channel_with_resilient_sound_clips

I hope this helps.

John

 

[jinglesmountjoy]

Thanks guys and yes, I will be inquiring as to permit needs.

Regarding your recommendations to use resilient clip method, I read the article John recommended and I would love to go that route but worry about only having that single wall as my only isolation. Is the resilient method THAT good that I can afford to lose the room-in-room? You are right, it would make the voice booth so much more roomy.

Rick, thanks for the tip on liveable size requirements for the VB...I'll definitely be sure to check on it.

The sheer amount of information I've been reading is daunting and borderline confusing. Do you know of any sources where I might be able to research decible blockage of various materials/methods so as to ascertain exactly what I might expect to block out with various building methods/materials?

I've attached a modified version of my previous design based on using the resillient clip method in my voice booth.

Thanks again guys for taking the time to post up.

 

[John Hile]

A clip/hat channel wall will perform really good especially if you can use 24" OC framing, insulation, double drywall and damping compound.

A room within a room or double stud wall is always going to be the best wall to start with. Again 24" OC framing, insulation, double drywall and damping compound. The space issue is something you'll have to work out, but by looking at your updated pic you may want that extra space. You may not be able to get that trombone quartet in there but you'll have a nice vocal booth for sure.

I work with many folks who use the clip/hat channel assembly and they are usually concerned with waking folks up in the house while dinosaurs run through their home theaters.

Yes. There is a lot of information out there. Good sound isolation can be attained if, as I mentioned in Post #2, you stick to the basic elements: 1-Mass, 2 Absorption, 3 - Decoupling, 4 - Damping
Here's a good article that explains this further: http://www.soundproofingcompany.com/index.php?/library/articles/elements_of_room_construction

Many folks assume that if you have an STC 45 wall and add a 27 STC panel to it that you will get an STC 72 but that's not how it works. This article should clear things up a bit for you:
http://www.soundproofingcompany.com/index.php?/library/articles/understanding_stc

I hope this helped.

How soon are you starting your build?

John

 

[jinglesmountjoy]

Thanks for the links John...those are just about the right speed for me. They take it down to my level...simple. It's just the read I needed. Now I need to find a reasonable price and place in my area to find these things.

Regarding timing of by build, I actually want to get started around 4 weeks from now (3rd week of November). My gameplan is to take a week off work and get it done all in one week. Should be quite tight!!