[Noisebridge-discuss] Build Team Progress

[Geoff Schmidt]

On Jul 17, 2009, at 10:21 AM, Andy Isaacson wrote:
> - the quiet areas will never be quiet if it shares airspace with the
>   rest of the space.

Speaking of sound, I did some research on this for another project.

The engineering statistic related to sound transmission through walls  
is STC (Sound Transmission Class.) Higher is quieter. A typical floor  
to ceiling drywall-on-studs interior partition wall would have an STC  
around 33, and you can hear speech through it. "Soundproofing" is  
about STC 50.

http://en.wikipedia.org/wiki/Sound_transmission_class

Suppose Noisebridge wants to have some sound-insulated spaces, for  
example for a shop or theater. Some options for increasing the STC of  
a floor-to-ceiling wall include:

* Sound-absorbing insulation in the wall. Doesn't really work.

* Soundboard underneath the drywall. A reasonable STC is claimed for  
this, but I have some friends who did this in a warehouse build and  
they were not pleased with the results.

* Two parallel sets of framing in each wall, with staggered studs, so  
as to eliminate the transmission of sound through the studs. Expensive  
and makes your walls twice as thick, but supposed to work well.

* Multiple layers of drywall on each side. You have to put on an awful  
lot of layers to get to STC 50 however.

* There is a product called QuietRock which works like a high-STC  
drywall and is well-reviewed.

Machine shops are louder than speech so your target STC might be  
higher than 50.

Price comparison, from the QuietRock vendor:
http://www.quietsolution.com/Installed_Cost_Comparison.pdf

geoff