Another Green Glue Question

Post and discuss acoustic topics, Studio design, construction, and soundproofing here

Re: Another Green Glue Question

Postby Yannick » Tue Oct 05, 2010 8:24 pm

I find this quite interesting.
As I have still to finish the inner construction of my floating 40m2 room (the floating slab is there), and was planning to finish the ceiling with 3 layers and 2 layers of green glue, this is really confusing. I did not find any corresponding test data as well - the second leaf in my case is a 26cm concrete floor+5cm PUR+7cm flowchape+2cm wood. Quite heavy and since the first leaf is suspended from beams resting on massive inner walls built on the floating slab of concrete, this is more or less a similar situation ?

I have been wondering for months if green glue is the way to go, or something like bitumen or this T50 thing.
Yannick
 
Posts: 130
Joined: Mon Nov 13, 2006 9:42 am
Location: Brussels

Re: Another Green Glue Question

Postby seb » Wed Oct 06, 2010 6:16 am

Yannick,

I am pretty sure that Bitumen and Tecsound-type products have only been demonstrated to have benefits related to an increase in mass and to ameliorating somewhat the coincidence dip.

Ted's comment earlier was that Green Glue should attenuate all resonances, including the Mass-Air-Mass resonance:
Postby Ted White » Mon Aug 30, 2010 2:38 pm
I would say that if the framing is competently decoupled, as with a double stud wall, damping would take a back seat to mass and cavity depth. Certainly damping will not affect the placement of the LF resonance point. Mass, cavity depth, and the presence of proper absorption (low/medium density insulation) will determine the MSM resonance frequency.

The presence of a damping compound would still reduce the effects of panel resonance at the MSM point through coincidence.


I have been given permission (I think) to publish the comparative test data for:

* 2x16mm fire-rated plasterboard
* staggered 64mm light gauge steel studs in a 92mm light gauge steel track
* Cavity insulation
* 2x16mm fire-rated plasterboard

The graph below shows TL for this wall with and without Green Glue. The Green Glue panels had been prepared some time before (weeks) at the rate of 2 tubes per 3.2m length of plasterboard sheet.
Clipboard07.png
Clipboard07.png (18.93 KiB) Viewed 2514 times


One of my colleagues has suggested that the stiffness of the framing may play a part in how effective the Green Glue is. Ted also made this suggestion earlier in the thread, although he thought plasterboard on more flexible studs would benefit more from Green Glue. Eric wasn't so sure.
seb
 
Posts: 43
Joined: Mon Mar 06, 2006 10:27 am
Location: Syddenny

Re: Another Green Glue Question

Postby Ido » Thu Oct 07, 2010 11:14 am

seb wrote:Yannick,

I am pretty sure that Bitumen and Tecsound-type products have only been demonstrated to have benefits related to an increase in mass and to ameliorating somewhat the coincidence dip.
..


don't be, they are 2 very different animals.
signature
Ido
 
Posts: 2201
Joined: Mon Feb 09, 2004 7:47 pm
Location: Israel

Re: Another Green Glue Question

Postby Ido » Thu Oct 07, 2010 11:33 am

seb wrote:....
The graph below shows TL for this wall with and without Green Glue. ..


this graph makes more sense to me than the one where the 2 lines where identical
.. I mean the 200-1200 hz range...
signature
Ido
 
Posts: 2201
Joined: Mon Feb 09, 2004 7:47 pm
Location: Israel

Re: Another Green Glue Question

Postby seb » Thu Oct 07, 2010 11:38 am

don't be

:)
Ido, care to share some tests? When I last looked at mass-loaded sheet products all I saw was higher TL that could be largely explained by increases in mass.

.. I mean the 200-1200 hz range...

Still not quite 8dB though.
seb
 
Posts: 43
Joined: Mon Mar 06, 2006 10:27 am
Location: Syddenny

Re: Another Green Glue Question

Postby Ido » Thu Oct 07, 2010 11:58 am

yo Seb,
as I said earlier, tecsound is not just mass, it's a dedicated damper, therefor should not be thrown in same family with bitumenan in an automatic response.
check out first, shoot later, not visa versa.
signature
Ido
 
Posts: 2201
Joined: Mon Feb 09, 2004 7:47 pm
Location: Israel

Re: Another Green Glue Question

Postby seb » Thu Oct 07, 2010 11:42 pm

Ido, I had definitely looked at some Tecsound TL data and saw nothing exciting. I definitely did not say that Tecsound doesn't "work". Every product usually does something - applicability comes down to actual performance, to project goals and constraints and relative costs. I try not to shoot first ... One of the impressive things about the Green Glue Company is that Brian has gone to great lengths to do back-to-back tests and to provide comparative construction costs (at least for the American market). Very few other product manufacturers do this, either because they can't be bothered or for the obvious reason (relative cost and performance). To date, though, almost all of Green Glue's acoustic testing has been done at Orfield, where it is not possible to do a comparative test of double-stud walls due to the flanking limits.
seb
 
Posts: 43
Joined: Mon Mar 06, 2006 10:27 am
Location: Syddenny

Previous

Return to Discussion

Who is online

Users browsing this forum: No registered users and 2 guests