ProSoundWeb Community

Sound Reinforcement - Forums for Live Sound Professionals - Your Displayed Name Must Be Your Real Full Name To Post In The Live Sound Forums => Installed Sound/Contracting => Topic started by: Nathan Riddle on December 22, 2016, 01:31:51 pm

Title: What to fill wall to minimize sound transmission
Post by: Nathan Riddle on December 22, 2016, 01:31:51 pm
I have a client building a new wall between two spaces (one loud, one with preschoolers).

Yes, I asked them if they could place the kids room further away, but can't.

What is the best material(s) that can be placed inside a wall (fire retardent, cheap, meets inspections, etc).

I'm thinking some mass loaded vinyl to block any Mid/Highs, liquid nails for the cracks, and good thick fiberglass insulation. Also, thicker wall (2x6 not 2x4).
Title: Re: What to fill wall to minimize sound transmission
Post by: Keith Broughton on December 22, 2016, 02:32:38 pm


I'm thinking some mass loaded vinyl to block any Mid/Highs, liquid nails for the cracks, and good thick fiberglass insulation. Also, thicker wall (2x6 not 2x4).
Seems like a good start.
The other thing to consider is sound damping inside the noisy (kids) room.
It helps to kill some of the sound before it gets to the walls.
Title: Re: What to fill wall to minimize sound transmission
Post by: Hanno Meingast on December 22, 2016, 02:36:38 pm
Double wall   Two sets of plates. Offset studs. Extra layers of drywall. Fill with rock wool


Sent from my iPhone using Tapatalk.    Hanno
Title: Re: What to fill wall to minimize sound transmission
Post by: Nathan Riddle on December 22, 2016, 02:47:22 pm
The other thing to consider is sound damping inside the noisy (kids) room.
It helps to kill some of the sound before it gets to the walls.

Good idea, they ran into issues with construction costing a good bit more than expected so that probably will have to come at a later date. The further issue is that the kids room has 48" walls instead of full walls. It is only separated by the louder youth room by a hallway and this new wall.

Thankfully, they are goign to try to stagger the loud portions of service in the youth room from the kids room. But still... going to be difficult to block sound.
Title: Re: What to fill wall to minimize sound transmission
Post by: Nathan Riddle on December 22, 2016, 02:50:53 pm
Double wall   Two sets of plates. Offset studs. Extra layers of drywall. Fill with rock wool

So sheetrock, rock wool & stud, sheetrock; sheetrock rockwool & stud, sheetrock? So its two walls physically there?

Or stacked plates?
Or two plates and thicker wall filled with rockwool?

I assume the offset studs help to keep any resonances down within the wall?
Title: Re: What to fill wall to minimize sound transmission
Post by: David Buckley on December 22, 2016, 03:34:31 pm
Here in NZ there is a kind of wall filler that is especially designed to reduce sound transmission, [linky (https://pinkbatts.co.nz/product-range/pink-batts-silencer-wall-acoustic/)]; you should have similar materials available in your jurisdiction.  There also a datasheet there which gives some guidance to how to do this and what results to expect.
Title: Re: What to fill wall to minimize sound transmission
Post by: Cailen Waddell on December 22, 2016, 04:15:32 pm
In addition to staggered studs, I would use double layers of drywall, with green glue between layers on both sides of wall, as well as hanging drawl on resilient channel off the studs.  All wall penetrations should be sealed with acoustic sealing caulk. 


Sent from my iPhone using Tapatalk
Title: Re: What to fill wall to minimize sound transmission
Post by: Laurence Nefzger on December 22, 2016, 04:51:25 pm
In addition to staggered studs, I would use double layers of drywall, with green glue between layers on both sides of wall, as well as hanging drawl on resilient channel off the studs.  All wall penetrations should be sealed with acoustic sealing caulk. 


Sent from my iPhone using Tapatalk
I am assuming that the two spaces are totally enclosed?! I have been amazed in the past to see attempts made to "sound proof" a wall between two areas yet have a drop ceiling with a shared plenum space.
Title: Re: What to fill wall to minimize sound transmission
Post by: Cailen Waddell on December 22, 2016, 04:54:41 pm
Right the wall has to go to the roof.


Sent from my iPhone using Tapatalk
Title: Re: What to fill wall to minimize sound transmission
Post by: Nathan Riddle on December 22, 2016, 05:37:00 pm
I am assuming that the two spaces are totally enclosed?! I have been amazed in the past to see attempts made to "sound proof" a wall between two areas yet have a drop ceiling with a shared plenum space.

Haha, that's great.

Yeah two story building, just filling in the space between floors.
Title: Re: What to fill wall to minimize sound transmission
Post by: Stephen Swaffer on December 23, 2016, 10:45:26 am

I assume the offset studs help to keep any resonances down within the wall?

To prevent sound transmission through the studs.  Sound doesn't just travel through air.
Title: Re: What to fill wall to minimize sound transmission
Post by: Keith Broughton on December 23, 2016, 10:52:01 am
What is the theory behind staggered or offset studs?
Title: Re: What to fill wall to minimize sound transmission
Post by: Ivan Beaver on December 23, 2016, 11:42:33 am
What is the theory behind staggered or offset studs?
The best thing to block sound transmission is MASS-AIRPSPACE-MASS.  With NO connection between the two mass walls. 

The idea is that walls would not be attached to each other.

So it acts as a vibrational isolator.

But this means starting the wall from scratch.  It will also make the wall thicker.

The problem in a typical contractor situation is finding a contractor who UNDERSTANDS the whole idea between sound isolation.

If they mess up the install, the whole idea starts to fall apart.

Often they don't understand why they are doing it and don't follow instructions.

You often have to be there AS THEY DO IT and watch them.

Because one the wall is covered up, you don't really know what they have done
Title: Re: What to fill wall to minimize sound transmission
Post by: Nathan Riddle on December 23, 2016, 12:01:12 pm
So really what I need to say is two completely built walls as the "MASS" with an airspace in between.

That's do-able, but I believe they are building the wall themselves and I need to give the specifications on doing said thing.

So:

Student, loud space.

1) Sheetrock + finish/paint
2) Rockwool & stud
3) sheetrock

4) airspace (1-2")

5) Sheetrock
6) Rockwool & stud
7) Sheetrock + finish/paint

Kids quiet space.

The main difficulty is putting both sheetrocks on the inner part of the wall.
Title: Re: What to fill wall to minimize sound transmission
Post by: Hal Bissinger/COMSYSTEC on December 23, 2016, 12:55:02 pm
I know in the past I have seen several designs for a sound proof deadening partition but I wouldn't know where to look now. Some might have been posted here. I remember special sheet rock from one manufacturer. You might check USG. Presenting the contractor with an architectural detail of the partition should eliminate any misunderstandings.

-Hal
Title: Re: What to fill wall to minimize sound transmission
Post by: Stephen Swaffer on December 23, 2016, 01:38:50 pm
I have dealt with installs where they used a sound deadening sheet material kind of as an " underlayment" material under the sheetrock don't know what is called but similar in look/ feel to ceiling tile.
Title: Re: What to fill wall to minimize sound transmission
Post by: Cailen Waddell on December 23, 2016, 03:42:11 pm
I have dealt with installs where they used a sound deadening sheet material kind of as an " underlayment" material under the sheetrock don't know what is called but similar in look/ feel to ceiling tile.
Homasote

I've seen it used in floors but not walls... 


Sent from my iPhone using Tapatalk
Title: Re: What to fill wall to minimize sound transmission
Post by: Caleb Dueck on December 23, 2016, 04:30:09 pm
Here's what I have seen-

-staggered studs with gap between the two walls
-studs 6"-12" rather than the standard 16" for each wall
-dual thickness sheetrock on the outer surface of each wall
- dual layers of MLV (Mass Loaded Vinyl) between the two walls.  See here for examples
http://www.asiproaudio.com/noise_barrier.htm

It works very well for sound transmitted through a wall.

Edited to add- don't forget doors and windows, any air gaps, and the ceiling.  Treating walls is only a quarter of the issue. 

For suspended grid ceilings, plan on ceiling tiles designed to block sound, then MLV or similar above, then absorption above that.  Bonded Logic cotton insulation, 8" thick, is flame retardant and works well, comes in 24" wide rolls.  This does a little to block sound, but more to knock down the sound bouncing between the ceiling tiles and the upper deck. 
Title: Re: What to fill wall to minimize sound transmission
Post by: duane massey on December 26, 2016, 02:36:56 am
Simplest, least expensive and most effective solution is basically what Iven spelled out pretty clearly. Two completely isolated walls which must extend all the way to the roof. Ceilings should be floating as well well, attached onlt y yo their relative room walls. Each wall space should be insulated. I've built three different DIY studis using these methods and was amazed at how well it works. If there is a common door you will need to do some thinking about the doors as well, but if there are no common (shared) doors, then a solid door in each location will probably be adequate. Saying all that, if your concern is noisy kids, not a live band or DJ, the basic double wall approach may even be overkill, but it will really work well. Other things can also cause concerns, especially shared duct work, shared ceiling space, etc. Maybe a drawing of the actual layout would help us, as well as the actual type of noise you are dealing with?
Title: Re: What to fill wall to minimize sound transmission
Post by: Ivan Beaver on December 26, 2016, 09:33:14 am
I think this might have been pointed out, but filling the wall with ANYTHING will just increase the sound transmission between walls.

Think of it this way-sound travels with less loss through ANY material-solid or liquid.

Even air.  There is less loss with high humidity than with dry air.

ISOLATION -floor to ceiling is the BEST thing.

If you can get 2 "limp mass" walls with air between, that is the winner.
Title: Re: What to fill wall to minimize sound transmission
Post by: Stephen Swaffer on December 27, 2016, 12:31:37 pm
Thinking on my keyboard here-so what you are saying Ivan is that a change in media affects the sound more? or is just the mass of the wall that absorbs the sound energy?  Sound travels through solids better than air-so at first glance it seems contradictory that placing a solid in the path would reduce the sound level-though through experience we all know it does.

I guess the actual mechanism is irrelevant to the discussion.-since the method obviously is effective.
Title: Re: What to fill wall to minimize sound transmission
Post by: Mac Kerr on December 27, 2016, 12:41:57 pm
Sound travels through solids better than air-so at first glance it seems contradictory that placing a solid in the path would reduce the sound level-though through experience we all know it does.

Sound travels faster in solids than in air, I'm not sure that equates to "better". Sound is attenuated somewhat any time it crosses a barrier. From air to a heavy solid barrier will have greater attenuation than from air to a thin film membrane. Heavy walls provide better isolation than thin walls, and a double heavy wall where the two walls are isolated from each other so there are multiple barrier transitions to make is better still.

Mac
Title: Re: What to fill wall to minimize sound transmission
Post by: Nathan Riddle on December 27, 2016, 01:13:34 pm
What constitutes as a 'heavy' wall?

More mass? Concrete, steel, lots of wood?

Isn't that what Ivan is saying NOT to do? "limp" walls with space (air) between them.

Attached is my current understanding of an easy to create, cheap, very good acoustic barrier.
Title: Re: What to fill wall to minimize sound transmission
Post by: Ivan Beaver on December 27, 2016, 02:45:02 pm
What constitutes as a 'heavy' wall?

More mass? Concrete, steel, lots of wood?

Isn't that what Ivan is saying NOT to do? "limp" walls with space (air) between them.

Attached is my current understanding of an easy to create, cheap, very good acoustic barrier.
Sheets of lead make a great wall.  They are heavy and limp.

If you can't do that, then double or triple thick sheet rock is a cheap way to do it.  Glue them together.  5/8" is better.

As per your drawing, you DO NOT want the studs to share the outside walls.

You can LIGHTLY fill the wall with LOOSE fiberglass.  DO NOT put it in tight-it will act as a "conductor".

But when loose-the actual air paths from wall to wall are longer-so it acts like a larger air gap.  Not huge-but a little bit.
Title: Re: What to fill wall to minimize sound transmission
Post by: Dave Garoutte on January 09, 2017, 05:14:13 pm
Non-rigid materials, by nature absorb energy: steel bad, rubber good.
Making the walls air-tight is important; No leaks.

Track down this book online:
SoundProofingSecrets By Craig Williams
Title: Re: What to fill wall to minimize sound transmission
Post by: Jean-Pierre Coetzee on January 14, 2017, 03:24:29 am
From my research I have done:

Two walls using wooden studs(don't use metal studs of any kind), there are "things" that exist, can't remember the name but the idea is to decouple the gypsum from the studs, you also want two layers of gypsum one laid horizontally one vertically. Complete air between the two walls, fill the walls with rock wool or fiberglass. From what I remember there is no real reason to put gypsum on the insides of the walls.

LINK (https://www.gearslutz.com/board/attachments/studio-building-acoustics/309888d1348192416-wall-construction-insulation-installed-wrong-need-advice-doublestudwall-topview.png)

(Sorry can't remember how to make the link clickable, will edit right)

I would as I said put the "thingys" between the gypsum and the studs as well, can't for the life of me remember what they are called, idea is to space the gypsum off the studs just barely.
Title: Re: What to fill wall to minimize sound transmission
Post by: Mac Kerr on January 14, 2017, 12:55:19 pm
(Sorry can't remember how to make the link clickable, will edit right)

There are instructions (http://forums.prosoundweb.com/index.php/topic,156618.0.html) in the top post in the "read before posting" forum.

Mac
Title: Re: What to fill wall to minimize sound transmission
Post by: Ivan Beaver on January 14, 2017, 05:40:03 pm
From my research I have done:

Two walls using wooden studs(don't use metal studs of any kind), there are "things" that exist, can't remember the name but the idea is to decouple the gypsum from the studs, you also want two layers of gypsum one laid horizontally one vertically. Complete air between the two walls, fill the walls with rock wool or fiberglass. From what I remember there is no real reason to put gypsum on the insides of the walls.

LINK (https://www.gearslutz.com/board/attachments/studio-building-acoustics/309888d1348192416-wall-construction-insulation-installed-wrong-need-advice-doublestudwall-topview.png)

(Sorry can't remember how to make the link clickable, will edit right)

I would as I said put the "thingys" between the gypsum and the studs as well, can't for the life of me remember what they are called, idea is to space the gypsum off the studs just barely.
Yes it is better to put 2 layers of sheetrock on the outside of the studs vs 1 layer on either side of the stud.

The single layers can tend to "re-transmit" the sound, while a double layer provides a better "mass barrier".

DO NOT stuff the walls with tight fiberglass or wool.  LIGHTLY put some in.

BE SURE to completely seal all outlets, switches and any other penetrations in the wall.   Use acoustic caulk.  It will stay flexible longer.

Even a very small hole can let A LOT of sound through.

When placing outlets or switches, be SURE to stagger them on opposite sides of the walls.

This way there is not a direct path through the outlet boxes.

It is often the little things and the quality of the job that makes a bigger difference than some actual materials.
Title: Re: What to fill wall to minimize sound transmission
Post by: John Rutirasiri on January 14, 2017, 11:48:21 pm
Non-rigid materials, by nature absorb energy: steel bad, rubber good.

I thought the denser fire-rated (type X) drywall would perform better than regular drywall, no?  What about Durock?
Title: Re: What to fill wall to minimize sound transmission
Post by: Lee Douglas on January 15, 2017, 10:46:39 am
there are "things" that exist, can't remember the name but the idea is to decouple the gypsum from the studs...

I would as I said put the "thingys" between the gypsum and the studs as well, can't for the life of me remember what they are called, idea is to space the gypsum off the studs just barely.

Jean-Pierre's "thingys" aka resilient channel:

http://www.auralex.com/product/rc-8-resilient-channel/ (http://www.auralex.com/product/rc-8-resilient-channel/)
Title: Re: What to fill wall to minimize sound transmission
Post by: Nathan Riddle on January 15, 2017, 09:29:32 pm
Just an update to my specific situation.

Client had a volunteer who builds sound proofing walls for hospitals help with the construction of the wall. He discussed some of the same things I suggested (y'all suggested).

Double wall wasn't used. Not sure of the double Sheetrock either (they are using the fireproof stuff so I assume denser?) anyways, not sure how it turned out as I was leaving before the wall was done.

Thanks for the suggestions! Good info here, great as a reference for future endeavors.