Soundproofing- Fact Or Myth - Building & Construction - Page 3 - DIY Chatroom Home Improvement Forum
Advertisement


Go Back   DIY Chatroom Home Improvement Forum > Home Improvement > Building & Construction

CLICK HERE AND JOIN OUR COMMUNITY TODAY...IT'S FREE!

Reply
 
Thread Tools Search this Thread
Display Modes
Old 08-11-2010, 02:53 PM   #31
Soundproofing Guy
 
Join Date: Jun 2009
Location: Michigan
Posts: 239
Rewards Points: 158
Default


HL, those are good questions.

5/8" is definitely better than 1/2". The added mass of the 5/8" is a huge benefit.

Clip systems are designed to hold double 5/8" drywall.

If you tore out the ceiling and added R19 fiberglass, then clip&channel to the bottom of the joists, then double 5/8" drywall with damping compound, you'd be glad you did. The biggest trend with home theaters (and all those subs) is to use three sheets of 5/8" rock, believe it or not. In this instance the clip pattern is adjusted for the added load.

Walls are decoupled with framing, not clips.
Ted White is offline   Reply With Quote
Sponsored Links
Advertisement
 
Old 08-12-2010, 08:11 AM   #32
Member
 
Join Date: Jun 2010
Posts: 45
Rewards Points: 25
Default


Quote:
Originally Posted by Proby View Post
My question is whether insulation does or does not help limit sound transmission.
It depends on: 1) the frequency of the sound, and 2) how the sound is transmitting 3) the natural frequency (resonance) of the wall.

The trick is getting the natural frequency of the wall system to be very different (and not on a harmonic) of the frequency you want to silence.


Insulation can help dampen the vibration of studs. So IF the sound is traveling through the studs, then it would help.

But insulation does nothing for the wall cavity volume. There's still air in the wall, insulated or not.

Think of a drum, both in open-ended and dual-head configurations. If you dampen the surface you are hitting, you dampen the drum- period. If the drum is open on the other end, then stuffing it with insulation alone may help because you are dissipating the sound energy before it gets out the bottom of the drum (assuming you're damping the drumhead at all, just airflow).

But if you have a second drumhead on the bottom, then the sound energy from hitting the top head will travel on a wave though the sealed air medium and to the other head-- coming out the other end mostly intact. This is due to the compressive effect of the sealed air chamber.

Manipulating the mass and stiffness of the system is the best way to reduce the resonance at a given range.

Reducing noise at the source is by far the most effective strategy, imo.

JH
Hohn is offline   Reply With Quote
Sponsored Links
Advertisement
 
Old 08-12-2010, 08:46 AM   #33
Soundproofing Guy
 
Join Date: Jun 2009
Location: Michigan
Posts: 239
Rewards Points: 158
Default


Thanks much for that informative post JH.

Quote:
Originally Posted by Hohn View Post
It depends on: 1) the frequency of the sound, and 2) how the sound is transmitting 3) the natural frequency (resonance) of the wall. The trick is getting the natural frequency of the wall system to be very different (and not on a harmonic) of the frequency you want to silence.
Quote:
Originally Posted by Hohn View Post


This is quite true. In practical terms, we want the resonance point (frequency) of the entire wall assembly to be not just different, but below the frequencies we are looking to stop. This is why wall construction becomes seemingly extreme when we build for low frequency (bass). If we’re looking to attenuate 80Hz waves, we need to be looking at a wall system with a resonance point below 50Hz. Establishing the wall resonance point higher than the frequency we are looking to stop doesn’t help us much.

Quote:
Originally Posted by Hohn View Post
Insulation can help dampen the vibration of studs. So IF the sound is traveling through the studs, then it would help.


Maybe not exactly like that. Insulation contact with the stud or drywall itself does not appreciably damp the vibration. The mass of the stud or panel is way too high relative to the damping of the insulation contact. The insulation is there simply to provide resistance to a sound wave within the cavity.

Quote:
Originally Posted by Hohn View Post
But insulation does nothing for the wall cavity volume. There's still air in the wall, insulated or not.


Obviously, that’s right. The air volume is fixed. Air alone has some resistance which will damp a sound wave over enough time and distance, however adding low density insulation to a sealed cavity will add significant resistance, and this is thermodynamically similar to simply having a much larger air cavity.

Quote:
Originally Posted by Hohn View Post
Manipulating the mass and stiffness of the system is the best way to reduce the resonance at a given range.


Again, in practical terms, this means decoupling the framing, adding absorptive fiberglass (or similar), using as much 5/8” drywall as is practical, and damping the drywall panels.

Quote:
Originally Posted by Hohn View Post
Reducing noise at the source is by far the most effective strategy, imo.

JH


Yes. No question since the if left unchecked, the sound will conduct along the framing and pop out who-knows-where.
Ted White is offline   Reply With Quote
Sponsored Links
Advertisement
 
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not 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 code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Soundproofing a common wall in semi-detached RichS30 Building & Construction 5 03-16-2010 10:04 AM
Soundproofing a Bathroom jbitt Remodeling 8 01-29-2010 10:53 AM
How to properly install Roxul soundproofing wool? renogirl Remodeling 6 04-23-2008 12:32 PM
Soundproofing a Semi party wall FLintonRice Building & Construction 20 04-11-2008 11:11 AM
Soundproofing help needed! Janis General DIY Discussions 7 09-10-2007 01:40 PM




Top of Page | View New Posts