Type of glass to use for booth "window"?

studiogenocide

New member
I was wondering if anyone had any ideas on the glass for the "window" into the recording booth. I am studying a 3/8" thick window glass @ 2' x 5'. I didn't know if plexiglass was better, and I cannot seem to find any info on it. Any help is appreciated!
 
I was wondering if anyone had any ideas on the glass for the "window" into the recording booth. I am studying a 3/8" thick window glass @ 2' x 5'. I didn't know if plexiglass was better, and I cannot seem to find any info on it. Any help is appreciated!

Check Table 3 on this page
http://www.eplastics.com/Plastic/Plastics_Library/Plexiglass-Noise-Reduction

In my humble experience, 3/8" glass is really thick and heavy...You will have to put heavier headers to hold it in place...but you can achieve the same noise reduction with a piece of plexi which will be thinner and lighter in comparison at the same reduction thresholds.
 
I am putting in a 3'hx6'w double plexi window in my studio. Did you use double stud build on your booth? If so, how wide is your air space between the two walls?

Using the two window approach is not easy, especially when you try to do it on a budget, but you can pick up plexi at a much better price for the size required. I called a glass company in my home town to check costs of having them do the 3x6 in glass and to install it. They quoted me over $1K... Plexi can work, but you will want to make sure you dont get two sheets that are identical in thickness. (I don't know exactly why, but it is all over the boards here).

Installing the plexi and keeping it free from damage is one tough thing. Just yesterday I installed 1 of the 3x6's and during the framing my drill slipped off the head of the screw and punched a hole in the now useless plexi. Just need to be careful. It also gets foggy with age, after scratches build up.

Any other questions I can try to offer up some advice.
 
Here is the bottom line. The principle is called WEAK LINK SYNDROME. It has to do with the actual TRANSMISSION LOSS of the booth assemblies. Here is how it works.

IF, you design booth ASSEMBLIES with a certain TRANSMISSION LOSS target, say 25db, it makes no sense to install a window assembly with a TL of 40. The floor, wall, cieling and door assemblys would allow sound to transmit at a lower energy than the window.

Here is an example. If your booth was constructed the same as a STANDARD WALL assembly, it would make NO SENSE to install a window assembly with two planes of 1/2" glass. Or vise versa. It would make no sense to build a DOUBLE WALL.. 2 leaf booth, and then penetrate one wall assembly with a plane of 1/4" glass.
Plexi can work, but you will want to make sure you dont get two sheets that are identical in thickness. (I don't know exactly why, but it is all over the boards here).
BTW, forget plexiglass...unless your booth is shiethed with cardboard.:D The key to transmission loss is MASS. Better yet...decoupled Mass.

This doesn't take into consideration flanking paths from venting ducts, door seals, decoupling from the floor etc. They all have a bearing on the overall transmission loss. BTW, same concept goes for the door.

No one can tell you what will really meet your needs without knowing how your booth is constructed. Even the glass "decoupling" design will make a huge difference. And you can't plan that untill you know the weight of the proposed glass.

Maybe if you give as some info on how your booth is built we might be able to suggest a viable solution.
fitZ:)
 
Check Table 3 on this page
http://www.eplastics.com/Plastic/Plastics_Library/Plexiglass-Noise-Reduction

In my humble experience, 3/8" glass is really thick and heavy...You will have to put heavier headers to hold it in place...but you can achieve the same noise reduction with a piece of plexi which will be thinner and lighter in comparison at the same reduction thresholds.

I am happy to inform you that your humble experience has brought you to a conclusion that is wrong.......

Don't you wonder for even a second why they give you TL values for pexi up to an inch thick - but stop with glass at 1/4" ? You wern't even a wee bit curious about that?

It's because glass out performs plexi hands down when you step into the rhelm of low frequency isolation.

It is the fact that it is (as you said) "really thick and heavy" that makes it out perform plexi - low frequencies require mass - lots of mass - glass has that - plexi doesn't........

To the original poster - if you have 2 layers of 5/8" drywall on each face of your wall assembly - then you should have your thinnest piece of glass (yes glass) a minimum of 1/2" thick annealed glass for side "A" and add 1/4" for side "B" - Thus a 1/2" flanked by a 3/4".

You can step down to 3/8" flanked by 1/2" if you use laminated glass instead of annealed.


Sincerely,

Rod
 
Don't know if it really makes a difference, but with the spacing on the top and bottom being different between the two sheets so one or both are angled. I've seen pictures of the pro studios and wondered if it really helped.
 
Okay- I know I am about to get chewed up here for having a symetrical room, but what I have is an 8 x 6 area. Nothing is up at this point except the interior wall portion which seperates the booth from the main room. I have done the best I can with what I have, so here goes: 2 x 4 walls all the way around with plain old insulation.
 
To the original poster - if you have 2 layers of 5/8" drywall on each face of your wall assembly - then you should have your thinnest piece of glass (yes glass) a minimum of 1/2" thick annealed glass for side "A" and add 1/4" for side "B" - Thus a 1/2" flanked by a 3/4".
:eek: Wow, you heard it from the pro! Hey guys, this reply is from the "expert of experts". Rod is an engineer an author of " Home recording studio- how to build it like the pros"(buy it!!)
http://www.amazon.com/Home-Recording-Studio-Build-Like/dp/1598630342

We're fortunate to have him as a member here. HEY ROD, long time no see!!:D Nice to see ya back!:)

BTW rod, how thick would the glass have to be to equal an assembly with TWO layers of 5/8" drywall on each face of a DOUBLE WALL with an air gap of say 12":eek::D
fitZ
 
Rick,

seeing as the mass doesn't change regardless of the air space in the wall (2 layers of 5/8" drywall) - and seeing as the 2 walls will automatically create the larger air space for the glass - the thickness of the glass doesn't change - it's still 1/2" flanked by a 3/4" (annealed).

And it's nice to "see you" too my friend.

Rod
 
Okay- I know I am about to get chewed up here for having a symetrical room, but what I have is an 8 x 6 area. Nothing is up at this point except the interior wall portion which seperates the booth from the main room. I have done the best I can with what I have, so here goes: 2 x 4 walls all the way around with plain old insulation.

You want a symmetrical control room. You may or may not want a symmetrical live room; you can work with either properly treated. A more fundamental question is if you are better off with a single larger room?
 
with TWO layers of 5/8" drywall on each face of a DOUBLE WALL with an air gap of say 12"


seeing as the mass doesn't change regardless of the air space in the wall (2 layers of 5/8" drywall)


I think you misinterpreted my description Rod. I did say...2 layers on EACH FACE. Thats twice the mass. What would the glass have to be now? 1" and 1 1/2" thick??:eek::eek::eek: Thats twice the mass, same as the drywall. Or does it work that way? :confused:
 
I think you misinterpreted my description Rod. I did say...2 layers on EACH FACE. Thats twice the mass. What would the glass have to be now? 1" and 1 1/2" thick??:eek::eek::eek: Thats twice the mass, same as the drywall. Or does it work that way? :confused:

Rick, when I sized the glass for the original poster I stated double layers of 5/8" drywall - so 2 layers on each face is staying the same. -

BUT - if the drywall was to become 4 layers each face - then yes the glass size would have to double as well.........

Equal mass is just that - equal mass........ and it has nothing to do with the air space.

Although the increase in air space with also increase he TL values of the wall - the mass still controls when punching a hole through it..........
 
To the original poster - if you have 2 layers of 5/8" drywall on each face of your wall assembly

Rick, when I sized the glass for the original poster I stated double layers of 5/8" drywall - so 2 layers on each face is staying the same. -

HOLY MOLY! It was me that misinterpreted your original reply Rod!:o:o geezus, getting old sucks!:D

No wonder the glass was 1/2" & 3/4". I thought you were telling the poster to use this for a NORMAL wall. My mistake. Ok, gottcha Rod, thanks a mill.
 
Hey Rod, one more question. Is it the weight of the glass equal to the weight of the drywall that makes equal mass? It would SEEM the combined weight of the two pieces of glass would be MUCH heavier than the drywall, but I've never calculated it. Thanks
 
Hey Rod, one more question. Is it the weight of the glass equal to the weight of the drywall that makes equal mass? It would SEEM the combined weight of the two pieces of glass would be MUCH heavier than the drywall, but I've never calculated it. Thanks


Rick,

As I explain in "the book" 2 pieces of 5/8" drywall is around 5.6 psf of mass - 3/8" annealed is only around 4.9 so it takes 1/2" to equal one side of the wall - the increase to 3/4" for the other side has to do with issues regarding coincidence.........

Sincerely,

Rod
 
I closed in a doorway... framed the inside of the door frame with 2"x6"s and used 2 pieces of regular 1/2" glass... Put about a 20 degree angle on the performance room side for deflection... the sound transmission is almost NONE..
 

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Rod, in my instance, where I have to work with what I have , which is 2 x 4 walls on 16 centers and plain insulation, what do I do about the window? Obviously I need two pieces, but at what angle and thickness? How far apart do the sheets need to be, and can it be done nicely on a 2 x 4 wall? Also, do you think I might do okay to double the amount of insulation used in the walls? I know it will take away from the actual insulation properties, but will it help to "deaden" due to the increased mass?

I know I sound like a real construction amatuer and there is good reason for that!
 
Oh, and one more thing Rod, when you state double layers of drywall, are you meaning you can hang drywall on yet another sheet of drywall with long enough screws to get in that stud? Again, please understand you are talking to an amatuer when it comes to construction! Have mercy!
 
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