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Author Topic: More STC dilemas  (Read 2088 times)

Dusk Bennett

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More STC dilemas
« on: December 20, 2008, 08:59:03 pm »

Hi guys,

Another problem. The Internet has gotten too big to efficiciently find data....

My plans call for Resillient Channel in my buildout. Problem is after the fact we modified the walls to 24" OC instead of 16 for better STC ratings. Unfortunately the Code does not allow for "Hat Channel" on ceilings beyond 16 inches.

I spoke with an engineer about the issue and he asked why I was even bothering with hat track under drywall and that I should use styrofoam insulation (instead of hat channel under the drywall) since it "performs better". He had no data to back this up. I do see certain types have high STC's but I cant seem to readily find any data that supports that off the shelf (Home Depot) 3/4" styrofoam sheets will equal the STC of hat channel.

The Owens Corning acoustical design guide does show hat channel as being a great insulator, which is why we are going with it, but it would sure help at this point if we could go with styrofoam altogether.

Has anyone else been here before? Any thoughts?

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Dusk Bennett
Artist Development/Production
Audio Engineering
Los Angeles CA
www.duskbennett.com

Thomas Jouanjean

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Re: More STC dilemas
« Reply #1 on: December 21, 2008, 05:59:00 pm »

Hi Dusk,

Forget the Styrofoam - it's bad news. Really bad in case of fire too.

If you can't use the resilient channel, dampen the structure with a heavy resilient material in sandwich between the gypsum boards. That will lower resonance freq and make the wall more efficient @ LF.

There are the green glue & co systems as well.

More details on the structure available? That would help...


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Thomas Jouanjean
Northward Acoustics - Engineering and Designs
http://www.northwardacoustics.com
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avare

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Re: More STC dilemas
« Reply #2 on: December 21, 2008, 08:13:52 pm »

Dusk Bennett wrote on Sat, 20 December 2008 20:59

My plans call for Resillient Channel in my buildout. Problem is after the fact we modified the walls to 24" OC instead of 16 for better STC ratings. Unfortunately the Code does not allow for "Hat Channel" on ceilings beyond 16 inches.Has anyone else been here before?

Any thoughts?


Resilient channel is not hat track.

Andre
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Dusk Bennett

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Re: More STC dilemas
« Reply #3 on: December 22, 2008, 11:54:56 am »

avare wrote on Sun, 21 December 2008 17:13

Dusk Bennett wrote on Sat, 20 December 2008 20:59

My plans call for Resillient Channel in my buildout. Problem is after the fact we modified the walls to 24" OC instead of 16 for better STC ratings. Unfortunately the Code does not allow for "Hat Channel" on ceilings beyond 16 inches.Has anyone else been here before?

Any thoughts?


Resilient channel is not hat track.

Andre


Thanks, after some research I figured that out. It's hard to believe that in a town as big as LA no one knows resilient channel. The one place that had it made me clarify the part NO's RC1 and RC2 before they actually said they had it...

What is the difference between hat channel and resillient channel? Few seem to know.
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Dusk Bennett
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Audio Engineering
Los Angeles CA
www.duskbennett.com

avare

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Re: More STC dilemas
« Reply #4 on: December 22, 2008, 10:47:10 pm »

Dusk Bennett wrote on Mon, 22 December 2008 11:54

What is the difference between hat channel and resillient channel? Few seem to know.



Hat channel is symmetrical with 2 equal legs for mounting to the base material.  Joists in this case.  RC has one leg.  The attachment shows several RC types.  It is taken from nrcc 44692, which also has test data on the effects of using RC.


index.php/fa/10753/0/[
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Thomas Jouanjean

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Re: More STC dilemas
« Reply #5 on: December 24, 2008, 06:22:51 am »

Nice document @ Andre. Thanks for sharing.

I will open a sticky where we can save all those useful links and documents in PDF.

RC is just one way to implement the deflection and decoupling principals really. It works for sure, but when facing the reality of construction sites and the complexity of some (well, most) structures - for example complex, angled, wall sandwiches which are further loaded with internal acoustic treatment which is anchored to it or needs to be anchored to the sub-structure - shows that in a majority of cases, the efficiency of those solutions decreases rapidly, they sometimes become more of a constraint than anything else really.

Not that they don't work, they do, but add a grain of salt.
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Thomas Jouanjean
Northward Acoustics - Engineering and Designs
http://www.northwardacoustics.com
http://www.facebook.com/pages/Northward-Acoustics/1062876633 71

Pro Audio Partners:
ATC Loudspeakers
FOCAL Professional Speakers

franman

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Re: More STC dilemas
« Reply #6 on: February 06, 2009, 12:52:44 pm »

Thanks for the nice illustration Andre...

RC1 is a 1/2" Resilient Channel
RC2 is a 1" Resilient Channel
(if I recall correctly)... We always seem to use RC1 when we specifiy Res Channel.

Andre's explanation on the hat channel is right-on.

fm
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franman

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Re: More STC dilemas
« Reply #7 on: February 06, 2009, 12:52:45 pm »

Thanks for the nice illustration Andre...

RC1 is a 1/2" Resilient Channel
RC2 is a 1" Resilient Channel
(if I recall correctly)... We always seem to use RC1 when we specifiy Res Channel.

Andre's explanation on the hat channel is right-on.

fm
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