Foam or Fiberglass for soundproofing? - Home Theater Forum and Systems - HomeTheaterShack.com

 
Thread Tools
post #1 of 8 Old 05-27-10, 02:23 PM Thread Starter
Senior Shackster
 
Ted White's Avatar
Ted White
 
Join Date: May 2009
Location: Michigan
Posts: 888
Foam or Fiberglass for soundproofing?

Hi all,

This is a common question, so perhaps some might find this interesting.

When we’re looking to soundproof a partition (wall or ceiling) we’d like to introduce Absorption in the otherwise hollow wall or ceiling cavities. Foam is a common consideration, however not appropriate for what we want. For damping the resonance in the air cavity, we prefer medium density fiberglass, cellulose, mineral fiber or polyester. All of these are open and “airy” enough to adequately interact with the sound waves.

Foams are not adequately open. “Open cell” foam is certainly better than closed cell foam, but not as high performance as something like humble fiberglass. Additionally, foam can couple the two sides of a wall or floor, allowing much better conduction of the vibration from surface to surface.

Foams are superior from a thermal perspective, but not a sound isolation perspective.

This might surprise some here, but when using insulation IN a wall or ceiling, it doesn't get any better than standard thermal insulation in a low / medium density, especially to control low frequencies. This could be fiberglass or medium density mineral fiber. http://www.nrc-cnrc.gc.ca/obj/irc/do...r693/ir693.pdf This extensive lab report conducted by the Canadian government has the data.

Seems counter-intuitive, and there are many companies that capitalize on the intuitive aspect of insulation as a solution to sound control. Also perhaps counter-intuitive, we never want to compress / compact (stuff) the insulation. The greater the compaction, the greater the conduction of vibration from one side of the partition to the other.

Further, there are only 4 soundproofing elements that we can bring to bear:

Decoupling
Absorption (insulation)
Mass
Damping

Of these 4, absorption brings the least to the table. We certainly want to install insulation where we are able, but know that the other 3 elements provide more demonstrable improvement.

Ted White

The Soundproofing Company
Ted White is offline  
Sponsored Links
Advertisement
 
post #2 of 8 Old 05-30-10, 09:34 AM
Senior Shackster
 
ejbragg's Avatar
Eric
 
Join Date: Dec 2009
Location: Dora, Ok
Posts: 193
Re: Foam or Fiberglass for soundproofing?

Ahh, practical sense, at last! Great info, Ted. Keep it coming!
ejbragg is offline  
post #3 of 8 Old 05-30-10, 09:42 AM Thread Starter
Senior Shackster
 
Ted White's Avatar
Ted White
 
Join Date: May 2009
Location: Michigan
Posts: 888
Re: Foam or Fiberglass for soundproofing?

Thanks. I find as time goes on, there are more and more nonesense products coming on the market that have no data, no lab tests and a predatory reliance on trying to tap into a customer's intuition. Sort of angers me.

Ted White

The Soundproofing Company
Ted White is offline  
 
post #4 of 8 Old 05-30-10, 10:01 PM
Senior Shackster
 
PepAX7's Avatar
Pep
 
Join Date: Mar 2008
Location: Bear, DE
Posts: 132
Re: Foam or Fiberglass for soundproofing?

Quote:
Ted White wrote: View Post
Thanks. I find as time goes on, there are more and more nonesense products coming on the market that have no data, no lab tests and a predatory reliance on trying to tap into a customer's intuition. Sort of angers me.
I'm with you, Ted. We find this in the electronics world, in all facets, and it just plain bugs me how these companies get away with "bilking" people whose lack of knowledge puts them in a "fact finding" mission. Of course, with the internet, anyone can start a blog and post whatever nonsense they like.

That's what makes the Shack work! Posting some of this science/research here, will help in that mission.

I haven't studied the Canadian report but plan on it. I've also been researching an insulation company named ROXUL, who publish their STC's on their website. Their Roxul AFB lists an STC of [email protected] for 4" material. That's pretty impressive to me.

I want to build some traps modeled after F. Alton Everest's designs and want to test out different materials for "tuning" the trap.

A builder/musician friend of mine say's he uses Roxul between adjoining townhouse walls and he swears by it for noise attenuation. It's all in the measuring, isn't it?

Thanks for your expertise!

Pep
PepAX7 is offline  
post #5 of 8 Old 05-31-10, 03:30 AM
Shackster
Darnstrat
 
Join Date: Jan 2010
Posts: 79
Re: Foam or Fiberglass for soundproofing?

What's been your experience using HDPE sheeting as a sound barrier coupled with rock wool?
Darnstrat is offline  
post #6 of 8 Old 05-31-10, 08:30 AM Thread Starter
Senior Shackster
 
Ted White's Avatar
Ted White
 
Join Date: May 2009
Location: Michigan
Posts: 888
Re: Foam or Fiberglass for soundproofing?

Hi Pep. Its all about the measuring is right. Having said that, studies in that referenced report show that fiberglass is slightly better in the low frequencies than mineral fiber.

Darnstrat: I haven't tested HDPE however its all about the mass. Whatever is heavy to build your leaves from. HDPE, MDF, Drywall.. All are heavy. It's a matter of cost and ease.

Ted White

The Soundproofing Company
Ted White is offline  
post #7 of 8 Old 06-02-10, 08:56 AM
 
Join Date: Jan 2010
Posts: 33
Re: Foam or Fiberglass for soundproofing?

Fantastic thread and initial post! Foam in the middle of a wall..... oy! what will be next?

The only thing I would like to add is my experience with insulating between leaves is that it also dampens the tympanic resonance of the drywall itself and thus providing a bit more isolation at the coincidence dip of the panel.

Fiberglass is cheaper than rockwool and you can get a contractor to install it for less than you would pay for the material alone due to their bulk purchasing power.

Now fiberglass for acoustic control within a space is a different matter.....

-ashley
bassman17 is offline  
post #8 of 8 Old 08-25-19, 10:33 PM
Shackster
 
Join Date: Aug 2019
Posts: 6
Re: Foam or Fiberglass for soundproofing?

soundproofing foam is the best option.
WilliamSmith is offline  
Reply

Bookmarks

Tags
fiberglass , foam , soundproofing

Quick Reply
Message:
Options

Register Now




PLEASE COMPLETE ALL REQUIRED FIELDS BELOW... THANKS!

REQUIRED FIELDS ON THIS PAGE
YOU MUST COMPLETE ALL OF THESE

Username
Password
Confirm Password
Email Address
Confirm Email Address
Random Question
Random Question #2




User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
PLEASE READ BELOW PRIOR TO ENTERING AN EMAIL ADDRESS!

ATTENTION!

YOU MUST ACTIVATE YOUR ACCOUNT!

Activation requires you reply to an email we will send you after you register... if you do not reply to this email, you will not be able to view certain areas of the forum or certain images... nor will you be able download software.

AN INVALID EMAIL ADDRESS WILL CAUSE YOUR ACCOUNT TO BE DELETED!

See our banned email list here: Banned Email List

We DO NOT respond to spamcop, boxtrapper and spamblocker emails... please add @hometheatershack DOT com to your whitelist prior to registering or you will get nowhere on your registration.


Email Address:
OR

Log-in










Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page



Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML is not allowed!
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

 


For the best viewing experience please update your browser to Google Chrome