how to build studio windows....?

Posted: Wed Mar 03, 2004 3:22 am

It is solid 1 inch thick glass, no frame. It is very heavy though.
I may have called it insulated, but I think what it actually is, according the the place that sells it,is that thick collapsable glass that they use for car windshields. It has a layer in between it somewhere (not that you can see) that is supposed to keep sound at a minimum. Ever noticed how well a good newer car can keep sound out? Same stuff I guess, only its thicker than a car windshield. But if I were to smack it with a hammer, it would shatter but not fall apart, just like a windshield would.
The difference between a 1/2 sheet and a 1 inch sheet of 2x4 ft is only like $10, so I figured why not get the 1 inch... they will be facing each other in 2 seperate walls about, ummm, 6 inches apart.
So whats the deal? Good, or bad? I can change it up if I have to, I just want it to work, and work well.
Thanks!

Posted: Wed Mar 03, 2004 5:37 am

Tubie,

Sounds like you have 1" laminated glass........there should be a very thin membrane visible between the two halves if you look around the edge. It is this membrane that dampens the tendency of the glass to vibrate.

Laminated, especially thick laminated is very good for studio windows, provided you mount it in the frame correctly and if you are using two sheets of 1" I don't think there will be too much sympathetic resonance to be concerned about.

Cool

(aka Ausrock)

Posted: Wed Mar 03, 2004 6:37 am

Tubedude,

Where did you buy this 1" thick laminated glass? What did a 2' x 4' piece cost?

Lee

Posted: Wed Mar 03, 2004 10:42 am

Cool, I knew it was good stuff!
I paid around $75 a piece for this stuff (good deal I think).
Just flipped open the phone book to "glass" and called a couple places. 1st place I called was the cheapest by about $20.

Posted: Wed Mar 03, 2004 3:37 pm

tubedude,

your solution is OK.
However the coincidence is around 500 Hz. If you still can alter it it should be good that you choose one window somewhat thinner to spread this coïncidence. Also note if this are 2 PVB layers of 0.38 mm or 1 of 0.76 mm in between 2 1/2" glas panes, the damping will be limitted, so the coïncidence still clearly present.

To Steve:
I tested the Insul program, and got some strange results. I have to check this further in-depth.
My Galaxy windows gave about 30 dB shortage versus real life measurements.

To all:
The concept sympathic resonance is often wrongly used here.
In windows one has free and forced bending waves and modal frequenties.
So the main resonances in the panes itself are defined by those modal frequencies but they are NOT defined by the thickness but the size and shape of the panes. And for the coincidence the same principles apply as for drywall.

If one uses the notion sympathic resonance one should define what one exactly means by that.

I am not going further in-depth here (time).
I'm not moderator, others are.

Warm regards
Eric

<small>[ March 04, 2004, 03:47 AM: Message edited by: Eric Desart ]</small>

Posted: Thu Mar 04, 2004 3:55 am

I can add a 1/2 inch piece of laminated glass into the fram with one of the 1 inch pieces with about 2-3 inches of air space between them. Good, bad?

Also, what is that chair shown at Galaxy? Is that a Swopper? If so, been wanting to try one of those weird things. Anyonehave any experience with those?

Posted: Thu Mar 04, 2004 4:14 am

Eric, did you test the free version of Insul or the paid one? The free one defaults to panel size of 2.7 m x 4.0 m, uses Sewell's correction plus edge damping. It also only allows float plate glass, not laminated.

What are exact size/thickness/air gap and type on Galaxy's windows, and which way was the 30 dB in error?

For a panel size of 1.2 x 2.4 m, 25mm thick glass with 150 mm air space, Insul shows STC 48 with coincidence @ 528 hZ and M-A-M resonance of 28 hZ - does this agree with your calculations? I'm more than slightly curious, because I was considering to buy the personal version of Insul. I hadn't seen noticeable errors in general wall calculations, and would like more options than the limited ones in the free version.

No rush, but if you get some time I would be grateful for your thoughts on this... Steve

Posted: Thu Mar 04, 2004 4:33 am

Steve,

I tried any combination in the free one (so I found which parameters could be influenced) and yesterday they sent me the complete version which I didn't install yet.

(PS: I really hope you forgive me but don't give this design)

I will do some tests next week and tell you.

Tubedude:
The larger the airspace the better. Rest OK.

Eric

Posted: Thu Mar 04, 2004 5:24 am

Eric, nothing to forgive - some secrets need to be kept, I was merely trying to understand and learn.

Which version did you buy? I'm looking forward to your impressions of it... Steve

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