soundproofwindows.com - any experience with their product?

[zulusound]

Greetings, I'm a newbie to this great site- thank you John Sayers! I just moved into a new house with a great basement space- unfortunately it is only about 2' below grade and there are 3 large windows facing the street. One of them is 10' wide! I do like the idea of using this natural light, and came across a website called soundproofwindows.com. Supposedly these windows are designed specifically for their acoustic properties, and are spring loaded to "mute" the windows. Anybody have any direct experience with this company? It would cost close to $3000 to get the 4 windows I would need, so I would like to know they would work. Also considering using "glass block" in the window sill. Thanks in advance!
Evan in Seattle

[sharward]

According to the manufacturer's Table of Window Noise Reduction, they are using STC as its yardstick. That measurement is practically meaningless in the context of studio design:

. . . "STC" does NOT translate to today's version of "real life" - it was developed for SPEECH isolation, not MUSIC, so it doesn't even CONSIDER anything below 125 hZ, and is centered around 500 hZ. Drums and bass have their main energy at or below the lowest frequency band that's even mentioned in STC calculation.

The human ear requires approximately 45 dB to hear frequencies at 50 hZ; (this value changes depending on whose study you look at) . . . (source)"

I also see that their "best" setup consists of two "soundproof" windows, plus a single pane window. That translates to a "three-leaf" design, which can be detrimental to transmission loss (TL). In other words, certain frequencies are actually louder with the introduction of the third window than if it were left out altogether.

There's some good window discussion in this thread... And this thread.

Using the search feature will turn up even more good stuff.

Hope that helps...

--Keith

[knightfly]

Keith's got you covered pretty well;

Not much info on glass bricks, except this

http://www.glassbrickcompany.com.au/pag ... nical.html

note their info is still only STC (not even that, but spec'ing it at 500 hZ the STC should be same or close) - gives weights at the bottom, you could compare to weight of gypsum panels (42 PCF) for an idea of relative mass. Their blocks are pretty small, only 3" thick and max of 9" square; so mass would be about 16 lbs per SQUARE foot, roughly equiv. to 7 layers of 5/8" gypsum wallboard.

Not bad, but this would be straight mass law, so a partition of one thickness of these 3" thick glass bricks would be somewhere around STC 42-45, with 50 hZ TL at around 32 dB.

Keep in mind these are ROUGH approximations... Steve

[sharward]

Sorry 'bout that... I totally missed the "glass block in the window sill" thingy.

[knightfly]

Hey, it's "Just another (glass) brick in the wall"...